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UBC Theses and Dissertations

A study of the principal spawning grounds and of the spawning of the lemon sole, Parophrys vetulus (Girard),… Taylor, Frederick Henry Carlyle 1947

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A STUDY OP THE PRINCIPAL SPAWNING- GROUNDS AND OF THE SPAWNING OF THE LEMON SOLE, PAROPHRYS VETULUS (GIRARD), IN THE GULF OF GEORGIA IN RELATION TO THE COMMERCIAL FISHERY by Frederick Henry C a r l y l e Taylor A Thesis submitted i n p a r t i a l f u l f i l m e n t of the requirements f o r the Degree of MASTER OF ARTS i n the Department of ZOOLOGY The University of B r i t i s h Columbia A p r i l , 1 9 4 ? TABLE OF CONTENTS Abstract Introduction i Condition of the Fishery 1 Regions Studied Major Lemon Sole Spawning Grounds i i i Location of the Spawning Grounds i v Methods 1 Coverage of the Regions , 1 Types of Information Sought 5 Analysis of Data Tot a l Catch and A v a i l a b i l i t y Studies 9 Tota l Catch 10 A v a i l a b i l i t y 11 Spawning Areas 18 Baynes Sound Region-Observations on the State- of Sexual Maturity 19 Evidence from Tag Recoveries 25 Boat Harbour Region Observations on the State of Sexual Maturity 26 Evidence from Tag Recoveries 30 Duration of Spawning Period 33 Baynes Sound .Region 36 Boat Harbour Region 37 Fishing Intensity 38 Growth Rates 49 Discussion of Fishing I n t e n s i t i e s 52 Population Changes ' 57 Dispersal of Lemon Sole from the Spawning Grounds 70 Population Differences 74 Stomach Analysis 76 Summary 83 Acknowledgements Literature Cited Appendix i ABSTRACT; The winter f i s h e r y f o r lemon sole i n the gulf of Georgia depends on populations spawning i n Baynes sound and Boat harbour from January to March. The peak period i n 1946 was from January. 24 to February 23 in- Baynes sound and 10 days e a r l i e r In Boat harbour. Although some spawning took place throughout the whole of both regions, with the exception of P o r l i e r pass, spawning' was more intense i n c e r t a i n areas of each region. Minimum estimates'of f i s h i n g i n t e n s i t i e s of 42$ and 26.3$ f o r the Baynes sound and Boat harbour regions respectively appear too heavy to maintain the f i s h e r y at i t s present l e v e l . During the 1947 f i s h i n g season Baynes sound was large l y closed to trawling; i n Boat harbour the percentage tag recovery was 6.3$ as compared to 18.8$ f o r the same period l n 1946v These recoveries.Indicated an average annual increase in length of 7.3$ or i n weight of 21.9$. Lemon sole spawning i n Baynes sound dispersed to parts: of the gulf, north of Nanoose bay, while those spawning' i n Boat harbour, dispersed "southward as f a r as the American boundary. Although these two populations do not mix" to an~ appreciable extent., t h e i r com-pos i t i o n i s very s i m i l a r except, f o r a larger number, of imma-ture and small mature f i s h In Baynes sound. The Por l i e r . pass population, consisting of two-thirds immature fish.,, d i f f e r e d markedly. An estimate of the amount of population change on the spawning grounds was made by comparing the variations i n tag returns per period calculated on the basis of a constant number of tagged f i s h available and a constant weight of f i s h caught each period. Stomach analysis showed that lemon sole do not' feed a c t i v e l y during the winter and""that f u l l y matured f i s h feed l e s s a c t i v e l y than- immature or spent i n d i v i d u a l s . Worms, clams, and b r l t t l e s t a r s formed the p r i n c i p a l foods. A STUDY OF THE PRINCIPAL SPAWNING GROUNDS AND OF THE SPAWNING OF  THE LEMON SOLE. PAROPHRYS VETULUS (GIRARD).  IN THE GULF OF GEORGIA IN RELATION TO THE COMMERCIAL FISHERY INTRODUCTION In 19^3 an Investigation of the otter trawl fishery was undertaken by the P a c i f i c B i o l o g i c a l Station. Hart (19-^6) i n his "Memorandum on the Otter Trawl Fishery", i n giving the reasons for undertaking t h i s i n v estigation, states, "An investigation of the o t t e r trawl f i s h e r y has been set up i n order to determine the nature and extent of the competition of otter trawls with other types, of f i s h i n g gear and the pos-s i b i l i t i e s of a continued successful otter trawl f i s h e r y . Considerations of the l a t t e r point depend upon studies of the species of f i s h caught, their general l i f e h i s t o r y and i n t e r r e l a t i o n s h i p s , the e f f e c t s of catching and releasing I l l e g a l , under-sized or otherwise unwanted f i s h , and the effects of dragging heavy nets over the bottom." The study of the lemon sole spawning grounds i n Baynes sound and Boat harbour, car r i e d out during January, February, and March, 19-^6, forms one phase of the general l i f e h i s t o r y studies of trawl caught f i s h . CONDITION OF THE FISHERY AND REASONS FOR THE SPAWNING GROUND  SURVEYS Hart (19^6) also makes the following statements about the condition of the otter trawl f i s h e r y i n the s t r a i t s of Georgia? "In general the fishery f o r otter trawl In the s t r a i t s of Georgia i s i n a depleted condition. This i s the re s u l t of the a c t i v i t y i n enclosed waters over a long period of years of a substantial f i s h i n g f l e e t which has been able to operate f a i r l y well throughout the year." The lemon sole spawning grounds i n t h i s area, were made the object of study both because the expl o i t a t i o n of spawning lemon sole constitutes one of the main, winter fisheries-, of this region and because of the b i o l o g i c a l i n t e r e s t i n spawning populations. These regions form two of the few " f l a t f i s h " spawning grounds well enough known to permit study. In t h i s survey information was sought on a number of problems which are- stated b r i e f l y below. These are enlarged upon i n l a t e r sections of th i s - r e p o r t . They are: 1. Does the a v a i l a b i l i t y (abundance) of the lemon sole vary during the spawning season? 2. What i s the v a r i a t i o n In the sexual development of the f i s h on or near the spawning grounds? 3. Does active spawning take place generally throughout the whole of a region or i s there more active spawning i n certai n sections of a region than i n others? 4. What i s the duration of the spawning season? 5» What i s the i n t e n s i t y of f i s h i n g on these spawning grounds? 6. What indications are there of mass movements of f i s h about or away from the spawning grounds? - i i i -7. To what regions of the gulf do the lemon sole from each spawning ground disperse a f t e r spawning? 8. Does a r e l a t i o n s h i p exist between the feeding of lemon; sole and the degree of sexual maturity? ; REGIONS STUDIED Major Lemon Sole Spawning Grounds As the gulf of Georgia has been Intensively prospected and fished by the trawler fleet- f o r many years now, there i s every reason to suppose that a l l the areas i n which lemon sole concentrate i n the wintertime to spawn.would be u t i l i z e d ! by the fishermen or at least known to them. Interviews with fishermen, and examination of cannery records and p i l o t house log books indicate that there are only three areas i n the gulf of Georgia i n which lemon sole are found i n s u f f i c i e n t quantities to provide a p r o f i t a b l e f i s h e r y . These are the Baynes sound, Boat harbour, and Point Atkinson-Fraser r i v e r areas. These regions y i e l d e d 5*$, 20$, and 7% respectively of the t o t a l lemon sole landings from the gulf of Georgia f o r the f i r s t three months of 19^6. For t h i s reason, therefore, the Baynes sound and Boat harbour regions have been assumed to be two of the major spawning areas f o r lemon sole i n the g u l f . Although some spawning i s known to take place o f f Point Atkinson, t h i s area i s not considered to be a major spawning area as the number of lemon sole taken there i s small; as f a r as i s known, no spawning takes place o f f the Fraser r i v e r mouth. r - i v -Looation of the Spawning Grounds The Baynes sound and Boat harbour regions have, f o r convenience, "been c a l l e d a f t e r the most widely known areas i n each region, although such areas may ac t u a l l y form only §, small part of the whole region. The locations, of these regions are shown on Map 1, and are described belowj The Baynes sound region' comprises that area between Denman and Vancouver islands, from Yellow rock l i g h t and Deep bay on the south to Comox and cape Lazo on the north. The area outside the Comox bar, south of cape Lazo, i s also included i n t h i s region. Baynes sound i t s e l f constitutes that s t r e t c h of water between Vancouver and Denman isl a n d s . The Boat harbour region i s bounded on the north by Dodd narrows and on the south roughly by a l i n e from Yellow point on Vancouver is l a n d to Blackberry point on Valdes i s l a n d . This region includes the top end of Stuart channel between Vancouver i s l a n d and De Courcy Island and that part of Pylades channel between De Courcy and Valdes islands from Ruxton passage south to Whaleboat channel. For convenience that part of Trincomali channel i n the v i c i n i t y of P o r l i e r pass has been included i n thi s area. Boat harbour I t s e l f i s on the Vancouver i s l a n d shore two and one-half miles south of Dodd narrows. Map.l. Gulf of Georgia: P o r l i e r Pass to Cape Lazo Scale: 1 649,000 METHODS In making t h i s study of the lemon' sole spawning grounds ( and of the spawning of the lemon sole, the methods employed involved three l i n e s of inv e s t i g a t i o n : 1. Studies of the size d i s t r i b u t i o n and sexual condition of the fish;: 2. Tagging- studies, to obtain information on f i s h i n g i n t e n s i t i e s and movements of the f i s h ; 3. A v a i l a b i l i t y studies. Coverage of the Regions-The in v e s t i g a t i o n was forwarded during January, through the use of the chartered vessel, " P h y l l i s C a r l y l e " . This vessel made f i v e t r i p s to both the Baynes sound and the Boat harbour regions. Her captain's knowledge of the f i s h i n g grounds i n each area proved invaluable i n obtaining samples from the l o c a l i t i e s most used by the fishermen. In February two t r i p s were made to the Baynes sound region and one to the Boat harbour region and i n March one t r i p was made to the Baynes sound region. In each of the major regions f i v e "drags" were made over definable courses. 4 I n the Baynes sound region these drags have been c a l l e d the "Deep bay", "Fanny bay", "Union bay", "Comox bay", and "cape Lazo" drags. The courses over which they were made are described below and are shown on Map 2. 1. Deep bay? from a point o f f the l i g h t at the entrance to Deep bay, down the centre of the sound to the southern t i p of Ship peninsula. coriox C O M O X \ H / \ R B O U R G O O S E S P I T U N I O N B-G O V ' T Wl 1 D E E P B A Y D R A G 2 F A N N Y B A Y D R A G 3 U N I O N B A Y D R A G C O M O X B A Y D R A G 5 C A P E L A Z O D R A G FANNY BAY SHIP PENINSI Map.2. Baynes Sound Region. Scale : 263,000 2. Fanny bay? from a point o f f the northern t i p of Ship peninsula, down the centre of the channel to a point o f f the f e r r y dock on Denman i s l a n d . 3. Union bay: s l i g h t l y westward of the centre of the sound from a point approximately opposite the government dock at Union bay, southward f o r a distance of about two miles. 4. Comox bay: s l i g h t l y to the east of the centre of the sound from the most westerly t i p of Sandy or Seal i s l a n d , northward f o r a distance of about two miles. 5. Cape Lazo: from a point about half a mile to the east of the l i g h t off Comox bar southward f o r a distance of • about two miles. The drags o f f Deep and Fanny bays were made i n 35 fathoms; of water, those o f f Union and Comox bays i n 23 fathoms, and that o f f cape Lazo i n kZ fathoms of water. In the Boat harbour region the f i v e drags have been c a l l e d " Boat harbour", "centre drag", "De Courcy i s l a n d " , "Pylades channel", and " P o r l i e r pass". The courses over which they were made are described below and are shown on Map 3. •The three drags^ of "Boat harbour", "centre drag", and "De Courcy i s l a n d " are situated across the top of Stuart channel, and run p a r a l l e l to each other. 1. Boat harbour:: on the west side of Stuart channel, close to the Vancouver i s l a n d shore, running from a point o f f Boat harbour i n a south-easterly d i r e c t i o n f o r a distance of about two miles. DODD NARROWS GABRIOLA ISLAND JFALSE NARROWS 1 B O A T H A R B O U R D R A G 2 C E N T R E D R A G 3 DE C O U R C Y I S L A N D D R A G 4 PYLADES C H A N N E L D R A G 5 POILIER PASS D R A G Map.3. Boat Harbour Region Scale: 89,000 - 3 -2. " Centre drag: i n the centre of t h i s part of Stuart channel, running between the same two points as above. 3. De Courcy i s l a n d : on the east side of Stuart channel, off the west shore of De Courcy i s l a n d , running from a point opposite Boat harbour, i n a south-easterly d i r e c t i o n to a point opposite the northwestern t i p of Ruxton i s l a n d . 4. Pylades channels down the eastern side of Trineomali channel from a point just north of Cardale point to a point opposite P o r l i e r pass. These f i v e drags were made i n approximately 35 fathoms of water. In Tables I and I I , the dates on which drags were made in the various areas are shown f o r the Baynes sound and Boat harbour regions respectively. On those t r i p s made during February and March samples could only be obtained from those areas i n which commercial trawlers were found f i s h i n g . The February 24th Union bay drag was made i n a s l i g h t l y d i f f e r e n t area than the other Union bay drags. This; drag, i n contrast to the others, extended to the edge of the Fanny bay area. A l l other drags made from commercial trawlers were i n the same areas as those made from the chartered v e s s e l . No haul was made o f f cape Lazo on the second t r i p , as the 11 P h y l l i s C a r l y l e " had to make an emergency run to Vancouver on the night of January 12. TABLE I BAYNES SOUND Deep bay Fanny bay Union bay Comox bay Gape Lazo T r i p 1 Jan. Jan. k 5 Jan. k Jan. k Jan. 5 Jan. 5 T r i p 2 Jan. 12 Jan. 12 Jan. 12 Jan. 12 — T r i p 3 Jan. 18 Jan. 18 Jan. 18 Jan. 1 8 , Jan. 19 Trip k Jan. 2k Jan. 2k Jan. 25 Jan. 25 Jan. 25 T r i p 5 Jan. 28 Jan. 28 Jan. 29 Jan. 29 Jan. 29 Tr i p 6 Feb. 13 Trip 7 Feb. 23 Feb. 24 Trip 8 Mar., .16 — Mar. 17 •a mtmmm > TABLE II BOAT HARBOUR Boat Oentre De Couroy Py lades- P o r l i e r harbour drag i s l a n d channel pass: Dec.28,19^5 Dec.28,19^5 Dec.29, Dec.30, T r i p A Dec.29,19^5 Dec.29,W5 19^5 19^5 T r i p 1 Jan. 7 Jan. 8 Jan. 1 Jan. 8 Jan. 9 T r i p 2 Jan. 15 Jan. 15 Jan. 15 Jan. 15 Jan. Ik T r i p 3 Jan. 20 Jan. 20 Jan. 20 Jan. 21 Jan. 20 Trip k Jan. 26 Jan. 26 . Jan. 26 Jan. 26 Jan. 27 T r i p 5 Jan. 31 Jan. 31 Jan. 30 Jan. 30 T r i p 6 — Feb. 16 A t r i p was made to the Boat harbour region on February 27, but as no trawlers were f i s h i n g there at that time, no samples i were obtained. One drag was also made of f Qualicum beach, two inside Nanoose harbour, and one on the east side of Kuper is l a n d . A l l drags were of approximately an hour's duration, with the exception of those made by commercial trawlers. Here the duration of the drag varied from one hour to two and one-half hours. For each drag the t o t a l weight of the " l i f t " , the weight of saleable f i s h , and the weight of each species of f i s h were recorded. Types of Information Sought In t h i s study work was concentrated on the following three types of investigations 1. Studies of the spawning condition of the f i s h . This; part of the work was undertaken to provide information about the duration of the spawning season and the i n t e n s i t y of spawning i n each area. A random sample of approximately 40 f i s h was taken from each drag and f o r each sample the following? data were recorded:: 1. The fork length of each f i s h . 2. The stomach contents. 3. The sex'- determined by actual examination of the gonads. The sexes can also be separated by an external examination only. In the female lemon sole the ovaries are contained i n pockets; formed by poster i o r extensions of the -6-pody cavity . These pockets l i e beneath the vertebral column, one on each side, and i n f u l l y mature f i s h can be traced as f a r back as the region of the caudal peduncle. As the ovaries mature they extend farther and f a r t h e r backward into these pockets. This extension of the ovary i n v i s i b l e , from an external examination 1, even i n immature females: and l s unmis-takeable i n mature f i s h . In male lemon sole no such pockets or extension of the testes are v i s i b l e . 4. The spawning condition. The spawning conditions of the female f i s h were rated i n s i x numbered categories with the following b r i e f definitions:: i . Immature - the ovary is; small and undeveloped, extending p o s t e r i o r l y only s l i g h t l y . i i . Maturing - the ovary i s developing, i t s posterior exten-sion was more marked. i l l . Ripening - the ovary i s well developed, distending the body walls; the posterior extension was very marked;: no clear' eggs are present. i v . Ripe - the ovary was well developed with clear, mature eggs present, scattered throughout the ovary or concentrated toward the anterior end. v. Running - eggs were extruded upon gentle pressure on the ovary. v?i. Spent - the f i s h had completed spawning;- the ovary con-tained no eggs and was often streaked with blood. Males were recognized only l n categories i . and v. 2. Tagging studies-. The reasons f o r undertaking t h i s type of investigation were threefold:; 1, To provide a means of estimating the f i s h i n g i n t e n s i t i e s . 2. To provide information about the movements-of the f i s h over the spawning grounds. 3. To Nobtain information about, the migration and dispersal of the lemon sole a f t e r spawning. From each haul a second random sample of 30 to 50 f i s h y&ice taken and tagged. The tags were of the standard button type used by the P a c i f i c B i o l o g i c a l Station's otter trawl i n v e s t i g a t i o n . They consist of a white,disc bearing the tag number and a yellow d i s c bearing the address of the P a c i f i c B i o l o g i c a l Station. The yellow d i s c i s placed on the eyeless, white side of the f i s h and the white disc on the eyed, coloured side, the discs, being held i n place by a n i c k e l pin passed! through the f i s h below the dorsal f i n at a point above and s l i g h t l y behind the pectoral f i n s . A reward of f i f t y cents, was; offered by the P a c i f i c B i o l o g i c a l Station f o r the return of these tags together with information on the place and date of recapture, the length of the f i s h and the condition of the f i s h and of the wound. For each f i s h tagged the following data were recorded:: 1. The tag number. 2. The fork length. ~ 3. The sex - determined from an external examination i n the manner described i n the preceding section. 4. An estimate of the spawning condition -such estimates were found to be accurate only i n the case of those f i s h f a l l i n g into category (v);; i t was not found pos-s i b l e to assign f i s h accurately to those categories dependent on the degree of ripeness; of the eggs without an examination of the gonads. 5. The weight - i n some cases the weight: i n ounces was recorded; a spring balance which, however, proved too d i f f i c u l t to read accurately i n rough-weather, was used. 3. ("Availability studies. : A v a i l a b i l i t y studies were undertaken to provide a background against which i n t e r p r e t a -tions of the f i s h i n g i n t e n s i t i e s and the movements of f i s h about the spawning grounds; could be made. The catches of lemon sole'for Baynes sound and Boat harbour were calculated f o r f o r t n i g h t l y periods during January, February, and March, 1946.. The t o t a l catch of lemon sole f o r the gulf of Georgia was obtained/from an examination of the records of the various wholesale f i s h dealers i n Vancouver and V i c t o r i a . With the aid of information obtained from p i l o t house log books, and from interviews with and l e t t e r s from those captains who d i d not keep log books, the t o t a l catch was proportioned into the catch per period f o r each region. The a v a i l a b i l i t y of the lemon sole In both region's, expressed i n pounds of f i s h per hour's dragging was. calculated f o r each period. This information was provided by an analysis; of the pilot house log books. These books were issued to a l l trawlers in 19-V? and 19^6 by the Pacific. Biological Station. In these books the captains recorded the number of hours fished each day, the area fished, the amount of each species caught, and information about the total weight of the l i f t and the weight of commercial species contained in i t . The layout of the pages contained in these books i s shown in Table XXVII of the appendix. Every second sheet is perforated and removable, so that, by making a carbon copy of each entry, the captain could retain a record of his fishing and at the same time provide the Pacific Biological Station with a duplicate copy. As- no compulsion was applied to make captains keep these log books, satisfactory detailed records were obtained from only approximately 30% of the trawler f l e e t . ANALYSIS OF DATA -TOTAL CATCH AND AVAILABILITY STUDIES The survey of the Baynes sound and Boat harbour lemon sole spawning grounds was conducted during January, February, and March, 19^6. Each of these months was divided into f o r t -nightly periods and the catch and availability (average catch per hour as calculated from pilot house log book records) were determined) for each period. Variations in the total catch and availability per period w i l l reflect major changes, in the abundance of lemon sole on the spawning grounds. These variations in abundance w i l l also affect the'pattern of tag recoveries and must be considered when these recoveries are used i n a quantitative manner, such as i n estimating the f i s h i n g i n t e n s i t i e s or i n i n t e r p r e t i n g mass movements of f i s h to and from the spawning grounds. This section deals primarily with the c a l c u l a t i o n and r e l i a b i l i t y of the figures obtained f o r the t o t a l catch and for a v a i l a b i l i t y of lemon sole f o r each period. The effects; of these factors on the f i s h i n g i n t e n s i t i e s and on any con-sideration of mass movements of f i s h to and from the spawning grounds are discussed i n the appropriate sections. Total Patch The t o t a l landings of lemon sole for January, February, and March, 1946, were obtained from the records of wholesale f i s h dealers i n Vancouver and V i c t o r i a . The coverage of these dealers was v i r t u a l l y complete; i n each c i t y the records of only two small wholesalers who would handle only a compara-t i v e l y small quantity of lemon sole were not examined. The figures obtained w i l l represent approximately the t o t a l amount of sole landed during t h i s period, and are probably the best estimate of the catch,that could be made. In every case the records examined showed the number of pounds of lemon sole landed, the date, and the. name of the boat making the landing, A boat's catch would often be. dividedl among several wholesalers. Therefore the data pro-cured from the wholesalers were rearranged and tabulated to show the t o t a l catch f o r each boat f o r each t r i p . From _ _ -11- _ information obtained from p i l o t house log books, from i n t e r -views with and l e t t e r s from the skippers, and sometimes from the composition of the catch alone, the areas i n which each boat had f i s h e d were determined. The three months, January, February, and March, were d i v i -ded into s i x periods of two weeks each, and the t o t a l catch made i n each r e g i o n f o r each pe r i o d was found. A f o r t n i g h t , was found to be the most s u i t a b l e p e r i o d to use as i t f i t t e d most nearly the average time between landings f o r a l l boats, thereby l a r g e l y e l i m i n a t i n g the n e c e s s i t y of s p l i t t i n g a land i n g between two adjacent p e r i o d s , yet s t i l l b e i n g s h o r t enough to show trends- i n catch and a v a i l a b i l i t y . The catch i n each r e g i o n f o r each p e r i o d i s shown i n Table I I I below: TABLE I I I PERIODS I I I I I I IV V VI BAYEE SOUID 30,731 39,766 33,384 48,117 35,698 26,669 BOAT HARBOUR 12,448 21,775 38,494 15,568 715 1,302 A v a i l a b i l i t y As was s t a t e d e a r l i e r , i n order to understand the p a t t e r n of tag r e c o v e r i e s , an a n a l y s i s of t o t a l catch records and abundance ( a v a i l a b i l i t y ) of lemon sole f o r each p e r i o d was necessary. The methods used i n ob t a i n i n g t o t a l catch records f o r each p e r i o d were described i n the preceding s e c t i o n . This -12-s e c t i o n deals w i t h the c a l c u l a t i o n s of a v a i l a b i l i t y . The a v a i l a b i l i t y (abundance) of lemon so l e f o r each p e r i o d i s expressed as the average weight of lemon so l e taken per hour's f i s h i n g , a f t e r the data, have been weighted to compensate f o r d i s t o r t i o n s introduced by boats f i s h i n g -• f o r p a r ts of a season and by the v a r y i n g f i s h i n g e f f i c i e n c i e s of the boats. The computations of a v a i l a b i l i t y are based on p i l o t house l o g book records. These records show the number of hours f i s h e d and the estimated weight of each species taken i n each l o c a t i o n v i s i t e d during the day. Unf o r t u n a t e l y , such records were kept c o n s c i e n t i o u s l y and continuously by only a small p r o p o r t i o n of the t r a w l e r s f i s h i n g these reg i o n s . However, p a r t i a l records kept by "c e r t a i n boats were found to be s u f f i c i e n t l y accurate to warrant t h e i r i n c l u s i o n . Records from the remainder of the f l e e t were r e j e c t e d because of apparent i n a c c u r a c i e s or omissions, such as the f a i l u r e to record the number of hours f i s h e d . The c a l c u l a t i o n s f o r the-Baynes sound r e g i o n were th e r e f o r e based on the records of two boats f i s h i n g f o r f i v e p e r i o d s , three boats f i s h i n g f o r two p e r i o d s , and four boats f i s h i n g f o r one p e r i o d ; and the c a l c u l a t i o n s f o r Boat harbour were based on the records of three boats f i s h i n g f o r f i v e or s i x pe r i o d s , three boats f o r •four p e r i o d s , two boats f o r two pe r i o d s , and f o u r boats f o r one p e r i o d . -13-The a v a i l a b i l i t y f o r a p e r i o d cannot be c a l c u l a t e d d i r e c t l y as the_average catch per hour's f i s h i n g due to d i s -t o r t i o n introduced both by boats f i s h i n g f o r only parts of a season during which the a v a i l a b i l i t y was not constant, and also by the v a r y i n g apparent f i s h i n g e f f i c i e n c i e s of the boats. These v a r i a t i o n s i n the apparent f i s h i n g e f f i c i e n c i e s of the boats can be a t t r i b u t e d to two causes; f i r s t , to the use by c e r t a i n boats of b e t t e r , more e f f i c i e n t gear handled by e x p e r i -enced crews, thereby producing a r e a l d i f f e r e n c e i n f i s h i n g e f f i c i e n c y ; and second, to the method of re c o r d i n g the hours f i s h e d each day, some boats r e c o r d i n g only the a c t u a l time the net was i n the water and.others the t o t a l time spent on the grounds each day, thereby producing an apparent d i f f e r e n c e i n f i s h i n g e f f i c i e n c y . There i s , however, no reason why the catch of boats f i s h -i n g only at the s t a r t of the season, when the a v a i l a b i l i t y was h i g h , should i n f l u e n c e the r e s u l t s more than the catches of boats f i s h i n g only towards the end of the season when the a v a i l a b i l i t y was obviously low, or why the catches of the apparently more e f f i c i e n t boats should i n f l u e n c e the conclu-sions more than the catches of the l e s s e f f i c i e n t boats, r e g a r d l e s s of the cause of t h i s v a r i a t i o n i n e f f i c i e n c y . These d i s t o r t i o n s were p a r t l y compensated f o r by the i n t r o d u c t i o n of two c o r r e c t i o n f a c t o r s i n weighting the data. These c o r r e c t i o n f a c t o r s have been c a l l e d the p e r i o d f a c t o r , which makes a compensation f o r boats f i s h i n g f o r only p a r t s of ~14« a season, and the boat factor, which makes compensation f o r the d i f f e r e n t f i s h i n g e f f i c i e n c i e s of the boats. The period factors a r e ; c a l c u l a t e d and applied f i r s t so that the boat factors are, calculated from data weighted to eliminate f l u c t u -ations i n a v a i l a b i l i t y . The boat factors are then applied to o r i g i n a l da,ta so that the f i n a l averages w i l l r e f l e c t v a r i -ations i n a v a i l a b i l i t y but not variati o n s produced by d i f -ferent f i s h i n g e f f i c i e n c i e s . These causes of d i s t o r t i o n are very s i m i l a r to those f o r which Hart (1933) wished to compen-sate i n c a l c u l a t i n g the catch for unit of f i s h i n g e f f o r t i n the p i l c h a r d f i s h e r y . He compensated for d i s t o r t i o n s produced by boats f i s h i n g for parts of a season by a method similar to the application of the period f a c t o r , but corrected for d i s -tortions produced by companies using equipment of d i f f e r e n t f i s h i n g e f f i c i e n c i e s by careful s e l e c t i o n of companies repre-sentative of the d i f f e r e n t f i s h i n g p o l i c i e s . As; the records of only a small number of boats were available, no such s e l e c -tion of boats representative of d i f f e r e n t f i s h i n g e f f i c i e n c i e s could be made; therefore the method of weighting by the boat factor was used i n compensating f o r d i s t o r t i o n s of t h i s type. These correction factors are calculated an'd applied i n the folloxiring manner. The t o t a l catch and the t o t a l number of hours fi s h e d by a l l boats i n a l l periods were determined. From these the seasonal average catch per hour's f i s h i n g was determined. The average catch per hour for each period was found by d i v i d i n g the sum of the catches of a l l boats l n each period by the number of hours f i s h e d i n that period. The period factor, f o r each period, was determined by di v i d i n g the seasonal average catch per hour by the average catch per hour f o r that period. The dail y catches of a l l boats i n a period were then m u l t i p l i e d by the factor for that period. By weighting the data i n t h i s manner compensation was made for boats f i s h i n g for only parts of a season. Next, the weighted d a i l y catches of• a l l boats i n a l l periods were summed and the sum divided by the t o t a l number of hours f i s h e d during the season. This gives a weighted seasonal average catch.per hour's f i s h i n g which i s approxi-mately equal to the unweighted seasonal average catch per ' hour. The weighted d a i l y catches of each boat i n a l l periods were summed and the sum divided by the t o t a l number of hours fished by that boat during the season, to give a weighted seasonal average catch per hour f o r each boat. The boat f a c -tor i s then found for each boat by div i d i n g the weighted seasonal average catch per hour by the weighted seasonal average catch per hour f o r that boat. In the case of those boats which fished f o r only a few days during the season, a c o l l e c t i v e correction factor was used. This was obtained by pooling the dail y entries of these boats and treating them as a u n i t . The average value so obtained would probably allow a better correction to be made for the varying e f f i c i e n c i e s of these boats than would i n d i v i d u a l factors based on the small catches and the few f i s h i n g hours of each boat. The -16-unweighted d a i l y catches of each boat were then multiplied by the factor for that boat. The d a i l y catches thus weighted, i n each period, were summed and divided by the t o t a l number of hours fished i n that period. This gave an average catch per hour's f i s h i n g f o r each period weighted so that variations; due to the di f f e r e n t f i s h i n g e f f i c i e n c i e s of the boats are largely compensated f o r but variatio n s due to perio d i c f l u c -tuations i n the abundance of lemon sole remain. These figures; are taken as representing the a v a i l a b i l i t y (abundance) of lemon sole i n each period. They are shown i n Table IV fo r the Baynes sound and Boat harbour regions. TABLE IV PERIODS I II III IV V IV BAYNES SOUND • 144.2 142.9 164.3 148.7 127.0 76.9 BOAT HARBOUR 150.5 140.4 • 137.3 114.6 61.3 13.4 It w i l l be noticed i n the above table that s 1. In Baynes sound there was an apparent increase i n a v a i l a b i l i t y during period I I I . The calculations for t h i s period were based on the records of only one boat whose catches per hour appeared consistently high throughout the entire season. To determine whether t h i s increase i n a v a i l a b i l i t y represents a s i g n i f i c a n t increase or whether i t was due to only p a r t i a l correction of the consistently high catches per hour recorded by t h i s boat, the mean dai l y catches per hour of t h i s boat for period III were compared to i t s mean da i l y catches per hour i n adjacent periods. The method used was to estimate the standard error of the differences between daily catches of, f i r s t , period I I I and period I I , then, period I I I and period IV, on the hypothesis that the means of the corresponding populations were equal. In both cases the application of " t " tests showed that, were the means of the populations equal, the differences observed could have arisen by chance alone approximately 60 times out of 100. Therefore the conclusion i s that the increase i n a v a i l a b i l i t y in period I I I was not due to an increase i n the abundance of lemon sole during t h i s period, but rather to the r e l a t i v e l y high adjusted catches which would obtain i n such a case as t h i s . 2. In Baynes sound there i s l i t t l e v a r i a t i o n i n the a v a i l a b i l i t y u n t i l the end of period IV, af t e r which i t drops rapidl y . 3. In Boat harbour the a v a i l a b i l i t y drops s l i g h t l y during the f i r s t three periods and then drops sharply during the l a s t three, 4. The marked decline i n a v a i l a b i l i t y started i n Boat harbour about two weeks before i t d i d i n Baynes sound. 5. The largest catches i n both areas were made l n that -18-period immediately preceding the s t a r t of the marked decline i n a v a i l a b i l i t y . The f a c t that the marked decline i n a v a i l a b i l i t y i n Boat harbour started two weeks before i t did i n Baynes sound might indicate that the spawning i n Boat harbour was about two weeks ahead of that i n Baynes sound. This f a c t i s also borne out by actual observations of the spawning conditions of the f i s h i n these regions. This marked decline i n a v a i l a b i l i t y i s attr i b u t e d to f i s h leaving the spawning grounds rather than to the large catches made i n the periods immediately preceding these declines. That such i s the case i s shown by the analysis of tag returns and i s discussed i n more d e t a i l i n that section. SPAWNING AREAS Evidence has been presented i n other sections of t h i s report to show that the Baynes sound and Boat harbour regions form two of the major, and probably the two major, lemon sole spawning grounds i n the gulf of'Georgia. The evidence f o r th i s was derived from: 1. Information obtained from commercial fishermen. 2. The t o t a l catches of lemon sole for the gulf of Georgia made during the spawning season. In t h i s section evidence w i l l be presented to show that spawning does not take place generally throughout a l l areas i n these regions, but i s more intense i n ce r t a i n areas than i n others. The data presented comes from tx«> sources: 1. Observation of the stage of maturity of the female lemon sole. Here sampled f i s h only were used as the estima-tions of sexual maturity f o r tagged f i s h were not found to be s u f f i c i e n t l y accurate f o r i n c l u s i o n . 2. An analysis of the returns of tagged f i s h recaptured on the spawning grounds. Each of the two major spawning grounds i s considered separately. 1. The Baynes sound region I. Observations on the State of Sexual Maturity As was stated i n the section on Methods, approximately forty f i s h , selected at random, were examined from each area on every t r i p . The spawning conditions were observed and noted i n the following six categories: 1. Immature, I I . Maturing, i i i . Ripening, i v . Ripe, v. Running, and v i . Spent. Males were recognized only i n categories i , i i , and v. F u l l d e f i n i t i o n s of these categories were given i n the section on Methods. In Table V are shown the number of lemon sole at each of the above stages of sexual maturity, found i n thevsamples taken i n the Baynes sound region. Where no entry appears f o r a t r i p , i n s u f f i c i e n t f i s h were available for precise examina-tion of the spawning conditions. TABLE V BAYNES SOUND  Spawning Condition - Female Area Date Pounds of F i s h per Hour 1s I II I I I IV V VI Total Spawning Condition - Male I II V Tot a l agging Female Male 200 9 5 20 0 1 1 36 1 0 2 3 100 10 5 14 0 0 0 29 1 3 7 11 150 . 11 6 15 1 2 2 37 0 2 2 4 200 11 1 16 2 1 2 33 1 1 5 7 100 6 1 20 2 0 5 34 0 0 6 6 50 37 1 5 2 1 4 50 0 0 0 0 15 0 8 0 1 18 42 1 0 7 8 30 18 0 3 2 1 44 68 4 0 21 25 150 9 1 13 4 2 1 30 1 0 13 14 100 5 2 12 2 . 1 1 23 0 0 17 17 200 4 5- 23 4 2 0 38 0 0 2 2 125 12 2 7 5 4 0 30 0 3 7 10 100 4 0 14 6 6 1 31 0 1 8 9 18 2 14 4 5 8 51 0 0 3 3 20 2 1 5 0 2 0 10 1 0 1 2 7 0 2 4 2 0 15 0 1 3 4 — 4 0 2 9 12 3 30 1 0 19 20 100 8 1 3 1 ,0 1 14 6 0 • 0 6 ,60 13 6 17 0 0 3 39 0 0 1 1 85 14 1 0 0 0 39 54 2 0 2 4 100 1 4 2 0 1 0 8 0 3 31 34 300 0 0 6 5 7 0 18 0 2 20 22 125 0 0 5 7 3 1 16 0 4 19 23 150 1 0 3 5 10 1 20 0 0 20 20 Deep bay Fanny bay Union bay Comox bay Cape Lazo - 4/1 12/1 18/1 24/1 28/1 13/2 23/2 15-16/3 4/1 12/1 18/1 24/1 28/1 13/2 12/1 18/1 24/2 12/1 17/3 19/1 25/1 29/1 1 o The points which are shown "by t h i s tabulation of the data are: 1. The y i e l d of f i s h per hoiar of dragging was greatest at cape Lazo, a l i t t l e l e s s i n Deep and Fanny bays, and le a s t i n Comox and Union bays. If lemon sole concentrate i n ce r t a i n areas to spawn the y i e l d of f i s h per hour's dragging w i l l be greater i n those areas than i n areas i n which spawning i s less intense. 2. Ripe and running females were taken i n a l l areas. 3. Giving consideration to the fac t that the Union bay February 24th sample, i n contrast to the others, was taken on the edge of the Fanny bay area, r i p e and running females can be said to be lea s t abundant i n Comox and Union bays and most abundant at cape Lazo and Fanny.bay. Deep bay was i n t e r -mediate. 4. The proportions of spent females are highest at Comox bay and at Deep bay. At the l a t t e r place the excess i s great enough to be s i g n i f i c a n t . 5» Chi-squared tests were applied to the data shown i n th i s Table to determine whether observed variations i n the proportions of f i s h at each stage of sexual maturity i n the various areas were s i g n i f i c a n t , or whether such variations could have arisen by chance. I f such variations, are s i g n i f i -cant, they would indicate that spawning i s more intense i n certain areas than i n others. The n u l l hypothesis set up was that the proportions of f i s h at each stage of sexual maturity i n each area were independent of the area. Assuming -22-that there i s ho association between the area and the number of f i s h at each stage of sexual maturity, the numbers of f i s h that would be expected to occur i n each c e l l of the table can be calculated from the marginal t o t a l s by simple proportions. Of the correctness of t h i s procedure, Simpson and Roe (1939) state, "The numbers of observations i n the two samples have nothing to do with association, nor have the. t o t a l numbers of observations f a l l i n g into any one category'. The marginal t o t a l s , i n other words, have no d i r e c t bearing on association, and i n any s p e c i f i c problem they are to be taken as given and Immutable.M The chi-squared test i s used, then, to determine what the p r o b a b i l i t y i s that deviations from the calculated cr--> expected d i s t r i b u t i o n equal to those observed could have r i s e n by chance i n samples or populations i n which the true propor-tions were those indicated by the t h e o r e t i c a l frequencies (Simpson and Roe, 1939). The formula for chi-squared was: chi-squared s S(x-m)^. m where x i s the observed value and m i s the expected value. The number of degrees of freedom can be found by the formula n s (r - l ) ( c - l ) , where r i s the number of rows, and c i s the number of columns i n the contingency table. For the number of degrees of freedom of the experiment a high value of chi-squared would refute the n u l l hypothesis. In the Baynes sound area tests were made on samples taken on comparable, dates l n Deep bay and Fanny bay, Deep bay and cape Lazo, and Fanny bay and cape Lazo. In Table VI are shown -23-tlie values of chi-squared and of P obtained f o r tidese t e s t s . In the last' column of t h i s table are shown the spawning condition classes which contributed most to the value of chi-squared. TABLE VI  BAYNES SOUND Areas Value of chi-squared Value D.SV of P. Spawning condition cate-gory contributing most to chi-sauared value Deep bay-s' anny bay 22.4912 5 L .01 IV, V, VI Deep bay-cape Lazo 75.6834 5 L .01 1, IV, V Fanny bay-cape Lazo 29.4626 5 L .01 1, V t i n column 4, "L" indicates "less than") As i n some cases the observed frequencies i n some c e l l s were small (below 5), continuity corrections were applied to obtain a better estimate of P from the chi-squared d i s t r i b u -t i o n . This adjustment may tend somewhat to underestimate the sign i f i c a n c e , however i n no case where a s i g n i f i c a n t difference was indicated by the unadjusted data, did the application of th i s adjustment reduce the l e v e l of pr o b a b i l i t y below .01. Simpson and Roe give the following reason f o r making t h i s adjustment, "...the d i s t r i b u t i o n of chi-squared i s continuous, while that of the frequencies i n a contingency table i s necessarily discontinuous. The chi-squared d i s t r i b u t i o n i s approached as a l i m i t by these discontinuous data, and i f the -24-frequencies are not uiiduly low the approach i s s u f f i c i e n t l y close to give a v a l i d estimate of P from chi-squared, but t h i s i s not r e l i a b l e i f the values of the table are determined largely by the very low frequencies i n i t . " The adjustment i s made by subtracting 0.5 from each observed frequency that i s higher than the t h e o r e t i c a l f r e -quency, and by adding 0.5 to each observed.frequency that i s lower than the t h e o r e t i c a l frequency. The calculations of the unadjusted and adjusted chl-squares are given i n Table of the appendix. In a l l cases the value of chi-squared obtained was large enough, at the number of degrees, of freedom of the t e s t , to indicate that the chances of the observed frequencies being drawn from the same populations as the c a l -culated frequency was l e s s than one i n one hundred. Further, the greater numbers of ripe and running females at cape Lazo and Fanny bay and of immature females at Deep bay contributed very l a r g e l y to the values of chi-squared obtained. Therefore the proportions of f i s h to each stage of sexual maturity l n an area i s dependent upon the area. The conclusion i s that:, though: some, spawning takes place throughout the whole reglon:,_ i t tends to be concentrated i n the areas o f f cape Lazo and Fanny bay. This i s shown both by the greater number of ripe and running females, and by the greater y i e l d s of f i s h per hour•s dragging taken i n these areas. The high proportion of spent females i n the areas at either end of Baynes sound, namely, Deep and Comox bays, -25-lndicates that f i s h captured there are moving o f f the spawning grounds. 2. Evidence from Tag Recoveries In Table VII are shown the^ recoveries- whose exact points of recapture are considered r e l i a b l e . Th.e- areas of tagging are l i s t e d v e r t i c a l l y and the areas of recovery h o r i z o n t a l l y . TABLE VII AREA OF . . . . AREA OF RECOVERY TAGGING Deep bay Fanny bay Union bay Comox bay Cape Lazo Deep bay 22 23 7 0 1 Fanny bay 8 12 3 0 2 Union bay 1 1 0 2 Comox bay 5 8 5 2 2 Cape Lazo 1 0 3 1 15 I t w i l l be observed i n t h i s table that: 1. Most tags were recovered i n Fanny bay and that the number recovered there i s greater i n each case than the number recovered from the area of tagging. This shows that there i s a movement of lemon sole from both ends of Baynes sound towards Fanny bay, the area of most active spawning within Baynes sound proper. 2. There i s a s l i g h t movement ocf f i s h i n both directions between cape Lazo and the areas within Baynes sound proper. As i t seems f a i r to say that most of these f i s h would be moving toward spawning areas, these recoveries of tags put out during January support the b e l i e f that Fanny bay i s the main spawning area i n Baynes sound. From the data derived from the state of sexual maturity of lemon sole i n various areas of Baynes sound and from the recoveries of tags put out during January, the conclusion i s that the 1946 spawning was most p l e n t i f u l off Fanny bay and cape Lazo. However, conclusions drawn from one year only cannot be applied too generally. For instance, one trawler captain of long experience expresses the opinion that the greatest concentration of spawning f i s h i n some years at least was i n the southern part of Union bay adjacent to Fanny bay. 2. The Boat Harbour Region 1. Observations on the State of Sexual Maturity The numbers of fish.found at each stage of sexual maturity have been tabulated according to t r i p and area and are shown i n Table V I I I . The pounds of f i s h per hour 1e drag are also shown i n t h i s table. TABLE V I I I BOAT HARBOUR Area Date Pounds of F i s h per Hour 1s Dragging I Spawning I I I I I Condition -IV V VI Female T o t a l Female Spawning Co n d i t i o n T o t a l I .11 V Male Boat 28/12/45 300 0 0 0 2 0 0 2 0 1 22 23 harbour 29/12 ~ 400 0 1 0 1 0 0 2 0 0 11 11 7/1/46- 113 0 0 7 5 2 0 14 0 6 26 26 15/1 — - 0 0 4 12 6 0 22 0 1 17 18 20/1 150 0 0 1 12 7 0 20 0 0 20 20 26/1 150 0 0 5 6 3 1 15 0 1. 24 25 150 0 0 8 8; 10 1 27 0 0 13 13 Centre 8/1/46 266 0 0 9 5 1 0 15 0 0 25 25 drag 15/1 150 0 0 12 12 5 1 30 0 1 11 12 20/1 150 2 0 9 7 8 1 27 0 1 12 13 26/1 150 0 0 14 13 8 0 35 0 0 5 5 31/1 60 0 0 17 5 14 5 41 0 0 15 15 De Gourcy 28/12/45 360 0 0 4 4 0 0 8 0 2 10 12 I s l a n d 29/12 0 0 8 1 0 1 10 0 1 7 8. 7/1/46 133 0 0 6 12 2 2 22 0 0 17 17 15/1 200 0 0 7 11 6 0 24 0 0 16 16 20/1 200 0 0 7 13 8 2 30 0 0 9 9 26/1 200 0 0 6 15 13 0 34 0 0 6 6 30/1 200 0 0 5 5 15 2 28 0 0 12 12 '16/2 1 0 9 7 19 4 40 0 0 10 10 Pylades 29/12/45 150 0 0 0 0 0 0 0 2 1. 3 6 channel 8/1/46 47 5 0 20 3 0 3 31. 0 3 1 4 15/1 40 1 0 . 17 3 0 2 23 1 5 10 16 21/1 80 6 3 7 0 0 2 18 3 1 6 10 26/1 50 6 0 4 0 0 0 10 0 0 0 0 30/1 t 75 5 0 8 2 3 10 28 0 0 4 4 P o r l i e r 30/12/45 200 7 0 13 0 0 0 20 0 0 0 0 pass 9/1/46 100 26 0 10 0 0 3 39 0 0 0 0 14/1 50 22 2 6 0 0 0 30 1 0 0 1 20/1 20 7 4 0 0 0 1 12 1 0 0 1 27/1 5 19 1 0 0 0 2 25 0 1 0 1 i I -28-It w i l l be noticed from t h i s table that? 1. The y i e l d of f i s h per hour's dragging was greatest In the De Courcy i s l a n d , centre drag,, and Boat harbour areas and least" i n the P o r l i e r pass: and Pylades channel areas. Here again, i f the f i s h are concentrating i n c e r t a i n areas to spawn the y i e l d per hour's dragging w i l l be greatest i n those areas l n which spawning i s most intense. 2. Ripe and running females were taken a l l over the area except at P o r l i e r pass. They were next l e a s t abundant at Pylades channel. 3. Immature and maturing females were most abundant at P o r l i e r pass and next most abundant i n Pylades channel. 4. The proportion of spent females i s greatest i n Pylades channel. This may be the r e s u l t of an accumulation of f i s h on grounds which are less, i n t e n s i v e l y f i s h e d . 5. Chi-squared tests were applied to the data shown i n the table to determine whether the proportions of f i s h at each stage of sexual maturity was.dependent upon the area. These tests were applied i n the same manner as they were to the Baynes sound data. In comparing any two areas, only samples taken on comparable dates were used. The calculations of chi-squared are given i n Table of the appendix. In Table IX on the following page are shown the values of chi-squared and of P obtained f o r comparisons, of areas i n the Boat harbour region. TABLE IX Boat harbour-De Gourcy Island BOAT HARBOUR Value of Value Spawning condition cate-Areas chl-aquared D.F. of P gory contributing most • ' " . to chi-squared value 1.5370 .95 - .90 Boat harbour-centre dr? De^ourcy i s l a n d -centre. drag  11.1730 5 .05 I I I , IV 13.9332 .01 I I I , IV Boat harbour-Pylades channel Oentre drag-Pylades channel 94.4268 L .01 IV, V, I 72.9966 1 .01 IV, V Boat harbour-P o r l i e r pass 147.5715 L .01 IV, V, I L .01 Pylades channel- 44.4657 5 P o r l i e r pass  (In column 4. "L" indicates "less than") I, I I I , IV These chi-squared tests indicate that: 1. The d i s t r i b u t i o n of sexual conditionswere about the same at Boat harbour and De Courcy i s l a n d . 2. The above two areas d i f f e r e d s i g n i f i c a n t l y from centre drag i n th e i r smaller proportion of ripening females and the larger proportion of r i p e females. 3. Running females appeared to be f a i r l y evenly d i s t r i -buted i n these three areas. - 3 0 -4. The d i s t r i b u t i o n s of sexual conditions i n Pylades channel d i f f e r e d s i g n i f i c a n t l y from.the d i s t r i b u t i o n s i n other areas. The smaller number of ripe and' running females found i n t h i s area, as compared to Boat harbour or centre drag, caused most of these differences. The smaller number of immature females and the r e l a t i v e l y greater number of ripening and ripe females found here caused most of the difference i n Pylades channel-Porller pass test.. 5. P o r l i e r pass d i f f e r e d s i g n i f i c a n t l y from a l l other areas. The large number of immature females and the small number of maturing and mature f i s h produced the.major portions of the differences observed. The conclusion i s that, though some spawning takes place throughout the whole of this, region with the exception of P o r l i e r pass, i t tends to be most concentrated i n the areas of De Courcy i s l a n d , Boat harbour, and centre drag. This i s shown by the greater' numbers of ripe and running females found i n these areas. The lack of r i p e and running females i n P o r l i e r pass indicates that no spawning takes place there. 2. Evidence from Tag Recoveries In Table X are shown the recoveries of tags from the Boat harbour region. -31-TABLE X AREA OF AREA . OF RECOVERY TAGGING Boat harbour Centre drag De Courcy i s l a n d Pylades channel P o r l i e r pass Boat harbour 22 0 6 »0 0 Centre drag 31 1 3 0 0 -De Courcy I s l a n d 34 1 7 0 Pylades channel 20 0 4 0 1 P o r l i e r pass 14 0 0 0 7 Only those tags returned by fishermen who were co n s c i e n -t i o u s l n g i v i n g complete and r e l i a b l e tag recovery data have been Included i n t h i s t a b l e . These fishermen., however, do not d i s c r i m i n a t e between the three areas l y i n g * across the top of S t u a r t channel, which have f o r convenience been c a l l e d Boat harbour, centre drag,, and De Courcy island., but r e f e r to them a l l as Boat harbour. This e x p l a i n s why most tags were recovered apparently i n the Boat harbour area. For those tags l i s t e d as being recovered i n centre, drag or De Courcy I s l a n d , the a c t u a l p o i n t s of. recovery, have..been d e f i ^ n i t e l y e s t a b l i s h e d . From t h i s t a b l e i t w i l l be observed t h a t : 1. The l a r g e p r o p o r t i o n of r e c o v e r i e s of f i s h tagged - 3 2 -i n Pylades channel were recovered In the three areas l y i n g across the top of Stuart channel. This would indicate a d e f i n i t e movement of f i s h from Pylades channel into the top of Stuart channel. There i s no evidence to show whether or not a reverse movement took place, f o r there was l i t t l e , i f any, f i s h i n g done i n t h i s area. 2. There i s some evidence from tag recoveries to show that the f i s h i n the three areas across.the top of Stuart channel mix quite f r e e l y . 3 . The number of recoveries of P o r l l e r pass tags i n the three Stuart channel areas and of tags from these areas i n P o r l i e r pass Indicate a d e f i n i t e movement of lemon sole beti^een these areas. As i n t h i s case i t again seems f a i r to say that most of the f i s h would be moving towards or away. from, ( i n the case of tags recovered i n P o r l i e r pass;) the spawning grounds, the evidence from these tag returns supports.the conclusions reached on the basis of the evidence derived from.the exami-nation of the state of sexual, maturity of f i s h _in the various areas. Therefore, the conclusion is . that., i n the Boat harbour region, the most intense spawning occurs i n the three areas l y i n g across the top of Stuart channel. Some spawning takes place i n Pylades channel, but i t i s less intense than that i n the above three regions. No spawning takes, place i n the P o r l i e r pass area. - -33-DURATION OF SPAWNING- PERIOD In determining;the duration of the spawning season, and i n following the Intensity of the spawning, during January frequent samples were taken from a l l areas, i n both regions. However, during February and March unfortunately only a few samples were taken at i r r e g u l a r i n t e r v a l s and from certain areas only. The examination of the ovaries.of the f i s h taken i n these samples gave some Indication of the duration of the spawning season and of the period of peak' spawning. Although not a l l the mature females on the grounds were found to be a c t i v e l y spawning f i s h , the proportions .of ripe and running f i s h increased as the season progressed. The number of r i p e and running females, and of running females only, expressed as a percentage of the total, number, of females i n a sample, were the c r i t e r i a used l n estimating the period of peak spawning. These data are shown i n Table XI f o r the Baynes sound region, and i n Table XII f o r the Boat harbour region. In the f i r s t three columns.of these tables the percentage of ripe and running females and the percentage of running females only, are shown for the three areas i n which spawning was most intense, l n the fourth column the percentage of r i p e and running females and of. running females only, taken on each t r i p are shown. TABLE XI BAYNES SOUND Deep bay. , Fanny bay Cape Lazo Total f o r Tri p T r i p No. Date ; ; :  (1946) Sexual Oondition Sexual Condition Sexual Condition Sexual Condition IV & V V T & S- IV & V V T & S IV & V V T & S IV & V V T & S 1 4/1 2.8$ 1.3$ 20.0$ 4.0$ 12.5$ 16.6$ 10.2$ 3.9$ 2 12/1 — . _ 13.0$ 3.8$ 5.0$ 2.1$ 3 18/1 8.1$ 5.4$ 15.9$ 5.5$ 66.6$ 26.6$ 25.0$ 10.6$ 4 24/1 9.1$ 8.8$ 30.0$ 13.0$ 62.5$ 21.9$ 27.0$ 12.1$ 5 28/1 5.9$ 1.4$ 38.7$ 15.6$ 75.0$ 40.0$ 34.0$ 16.4$ 6 13/2 6.0$ 17.6$ 8.1$ 12.0$ 8.1$ 7 23/2 2.4$ ' 3.4$ . - — — i , _ 30.6$ 16.5$ 8 15/3 4.4$ 1.5$ 2.5$ 0.8$ f Columns marked V T & S ref e r . t o the running females found among the f i s h tagged and the f i s h sampled considered together for each t r i p . Columns marked IV & V r e f e r to ripe and running females among sampled f i s h only. TABLE XII ; BOAT HARBOUR . Boat Harbour Centre drag De Courcy Island Total f o r T r i p T r i p No. Date . - Sexual Condition Sexual Condition Sexual Condition Sexual Condition I V & V V T & S IV & V V T & S I V & V V T & S I V & V V T & S A 1945 28/12 22.2$ 36.0$ 6.0$ 1 1946 ?7/l 50.0$ 22.7$ 40.0$ 20.0$ 63.6$ 34.4$ 36.6$ 26.8$ 2 15/1 81.8$ 66.6$ 56.7$ 31.8$ 70.8$ 10.0$ 55.5$ 25.0$ 3 20/1 95-0$ 69.2$ 55.6$ 33.3$ 70.0$ 33.3$ 57.8$ 31.5$ 4 26/1 60.0$ 23.0$ 60.0$ 32.0$ 79.0$ 56.5$ 54.3$ 31.3$ 5 31/1 66.6$ 22.2$ 46.0$ 36.0$ 75.0$ 61.1$ 56.8$ 31.8$ 6 16/2 — — 65.0$ 70.5$ 65.0$ 70.5$ Columns marked V T & S r e f e r to the running females found among the f i s h tagged and the f i s h sampled considered together f o r each t r i p . Columns marked IV & V r e f e r to ripe and running females among sampled f i s h only. Further indications concerning the duration of the spawn-ing season i n each region can be obtained from the figures for a v a i l a b i l i t y (average catch per hour) for each period. Baynes sound region ' From Table XI i t w i l l be noticed that I 1. Some r i p e and running females were found at the start of the period of inv e s t i g a t i o n . 2. The percentage of ripe and running females increased steadily up to the end of January. 3. The percentage of r i p e and running females i n the samples taken on February 13 and 23 are of the same order as those for samples taken at the end of January. 4. The percentages of ripe and running females i n the samples taken on March 15 and 16 are small. 5. The percentage of spent females i n the samples increased steadily during the whole period under consideration. From the above data the conclusion i s that the period of peak spawning i n Baynes sound i n 1946 was roughly from about January 24 to February 23, though some spawning took place i n the f i r s t part of January and i n March. Spawning probably reached a peak s l i g h t l y e a r l i e r i n the cape Lazo area. In t h i s area considerably fewer immature and maturing females were found and hence the percentages.shown i n Table XI are higher than for other areas i n Baynes sound. The decline i n a v a i l a b i l i t y (see Table IV, page 16) from period V (March 1 - 15) to period VI (March 16 - 31) indicates that the f i s h are leaving the spawning grounds at t h i s time and lends further" weight to the conclusion that most of the spawning i s completed by March. Boat harbour region From Table XII i t w i l l be noticed that I 1. The percentages of ripe and running females and of r i p e females only In the samples from t h i s region were considerably greater than i n the Baynes sound region. This i s because, i n the Boat harbour region, few immature or maturing female lemon sole were found as compared to the numbers found i n Baynes sound. 2. Some r i p e and running females were found at the start of the in v e s t i g a t i o n . 3. The percentage of ripe and running females increased steadily throughout January, possibly reaching a peak about the end of January. 4. Not enough samples were taken a f t e r the end of January to follow the course of the spawning beyond,this date. On the basis of these data the conclusion Is that peak period of spawning i n Boat harbour starts about January 15 and continues u n t i l the end of January, and probably into the f i r s t part of February. There l s a marked decline i n a v a i l a b i l i t y (Table IV, page 16) i n the Boat harbour region from period IV (February 16 - 28) onwards. This would indicate that the f i s h s t a r t to leave the grounds about the middle of February. This supports the b e l i e f that most spawning i s completed i n t h i s region at i e a s t by- the end of" February and probably by the middle of that month. Spawning i s completed a l i t t l e e a r l i e r i n the Boat harbour region than i n the Baynes sound region. FISHING INTENSITY In Tables XIII and XIV are shown the returns for each period of f i s h tagged on each t r i p made to the Baynes sound and Boat harbour regions r e s p e c t i v e l y . At the foot of each table i s shown the unadjusted f i s h i n g Intensity for that region, as indicated by these returns. TABLE XIII BAYNES SOUND Trip Date Tags No. (1946) Used TAGS RECOVERED Periods I II III IV V VI Jan. Jan. Feb. Feb. Mar. Mar. Tags _Re co-vered After 1 Jan. 7 160 11 17 14 13 2 1 . 3 . 2 Jan.12 110 4 13 9 14 3 1 5 . 3 Jan.18 137 - 14 11 9 7 1 2 4 Jan.24 144 - 7 18 21 9 1 4 5 Jan.28 130 - 5 8 19 5 2 6 6 Feb.13 39 - - 0 ' 9 4 0 2 7 Feb.23 94 - - - 5 9 0 5 Total 814 I1? 60 90 3? 6 27 Total no. of tags Fishing i n t e n s i t y out s 266 BT4" 814. T o t a l no. = 32.7# of recoveries = 266 TABLE XIV BOAT HARBOUR TAGS RECOVERED Tr i p Date Tags '  No. Used Periods Tags Recovered I II III IV V VI After Jan. Jan. Feb. Feb. Mar. Mar. Mar. 31 1-15 16-31 1-15 16-28 1-15 16-31  A 1945 Dec.28 - 31 425 5 26 12 7 4 4 17 1 1946 Jan. 7 203 0 20 13 2 3 1 13 2 Jan.15 160 0 17 11 3 0 0 12 3 Jan.20 150 - 12 13 6 0 1 14 4 Jan.26 120 - 8 9 2 2? 1 10 - 5 Jan.30 120 - 0 24 6 4 1 9 6 Feb.16 49 - - - 2 2 3 2 Total 1,227 5 83 82 28 15 11 77 No data on 7 recoveries: 5 from t r i p A, 1 from t r i p 1, 1 from t r i p 3 E f f e c t i v e number of tags out - 1,220. Total no. of recoveries = 301 Total no. of recoveries to end of March s 224. Fishing i n t e n s i t y : T r i p A included:' 224 „ 18.3$ 1,220 T r i p A excluded: 166 _ 20.8$ 800 -40-The sum of tag returns, from every tagging operation, expressed as a percentage of the number of f i s h tagged, has been termed the f i s h i n g i n t e n s i t y . This w i l l represent only approximately the true f i s h i n g mortality, that is., the rate at which f i s h are being removed from the grounds by the fishery, because of the effects of: 1. Natural mortality. 2. Tagging mortality. 3. Loss of tags from l i v e f i s h on the grounds. 4. Loss of tags' a f t e r recapture and before return. 5. Emigration of tagged f i s h . 6. Immigration of untagged f i s h . These s i x factors a l l tend to reduce the numerator of t h i s expression, leaving the denominator unchanged; the f i r s t three and the l a s t two by reducing the number of l i v e tagged f i s h on the grounds available to the fishermen, and the fourth by reducing the actual number of tag returns received. For these reasons the f i s h i n g i n t e n s i t y , as indicated, w i l l be less than the f i s h i n g mortality r a t e . As no data are avail a b l e on which to evaluate the extent of the e f f e c t s of any of these factors i n the estimated f i s h -ing i n t e n s i t y , only the following general assumptions of t h e i r possible e f f e c t s can be made: 1. For the comparatively short period under consideration the effects of natural mortality and the loss of tags from f i s h on the grounds w i l l probably be small and could safely be •ignored. - i a -2. Tagging mortality may possibly have reduced the true f i s h i n g i n t e n s i t y considerably. The mortality included under t h i s heading could a r i s e from two sources: 1. Injuries received when the f i s h are caught, produced by the pressure of the f i s h i n the net or by abrasions from the web. 2. Injuries and i n f e c t i o n s produced by the tagging operation. If tags are either too t i g h t or too loose they are l i a b l e to chafe and cause open sores which could conceivably cause the death of the f i s h . In tagging every e f f o r t was made to mini-mize as f a r as possible the effects of i n j u r i e s from these sources; only apparently uninjured f i s h were tagged, and the tags themselves were c a r e f u l l y put on. 3. The loss of tags a f t e r recapture and before return remains a source of error that cannot be ignored and whose possible effect can only be approximately assessed. Some tags might have been l o s t through the indifference or carelessness of fishermen or cannery employees, but thisnumber i n a l l p r o b a b i l i t y i s small as every e f f o r t was made to impress on those handling lemon sole, the. d e s i r a b i l i t y of returning tags promptly together with the pertinent recovery data. The method of expressing the returns as a percentage of the t o t a l number of f i s h tagged introduces another source of error which would also make the indicated Intensity some-what lower than the true f i s h i n g i n t e n s i t y . The calculation: -42-of the f i s h i n g i n t e n s i t y i s based on the assumption that a l l the tags were out at the s t a r t of the season and henoe a l l were a f f e c t e d e q u a l l y by the f i s h e r y . I n r e a l i t y , the tags were put out during the course, of the f i s h i n g season so t h a t those f i s h tagged towards the c l o s e of the season d i d not have as much chance of being caught as those tagged at the s t a r t . This e r r o r can be c o r r e c t e d by weighting the data so that a l l tags appear to have an equal chance of recovery. The method used was suggested by Dr. J . L. Hart and i s des c r i b e d below. Table XV shows how the c a l c u l a t i o n s were made f o r the Baynes sound r e g i o n . TABLE XV BAYNES SOUND  Column 1 Column 2 Column 3 Column 4 P e r i o d Tags used Tags recovered F i s h s t i l l Column 1 x to be Column 3 I 270 102 242,681 65,523,870 I I 411 137 199,696 82,075,056 I I I .39 13 155,093 6,048,627 IV 94 14 105,398 9,907,412 T o t a l s 814 266 702,868 163,55^,965 _4 _ 163.554.965 « o n Q « 9 (Recovery s u s c e p t i b i l i t y 1 - 814 - * 0 0 * w f a o t o r ) T o t a l Column T o t a l Column T o t a l Column 2 x T o t a l Catch = 266 x 261.420 Recovery s u s c e p t i b i l i t y f a c t o r 200,927 * Adjusted F i s h i n g I n t e n s i t y -» = 42.5$ - 4 3 -Fi8h were tagged i n the f i r s t four periods only. The t o t a l number tagged i n each period i s shown i n Column 1. In Column 2 are shown the number of recoveries made during the whole season from each period's tagging. ,The number of pounds of f i s h caught from the mid point of each period u n t i l the end of the season was calculated -and tabulated i n Column 3 . Column 4 shows the product of Column 1 and Column 3 . Each column was summed and the sum of Column 4 divided by the sum of Column 1. This gives a factor which represents the suscep-t i b i l i t y of a tag to recovery. The sum of Column 2 m u l t i p l i e d by the t o t a l catch f o r the season and divided by the above factor gives the total, number of tags which would have been recovered had a l l f i s h "been tagged at the s t a r t of the season. This number expressed as a percentage of the t o t a l number of f i s h tagged represents the adjusted f i s h i n g i n t e n s i t y . The catch per period i s expressed as occurring at the mid point of each period and the tags as i f they were a l l out at the start of a period. The error introduced by. t h i s procedure w i l l be small. Before being used, the figures f o r the t o t a l catch f o r each period were adjusted so as to represent more nearly the tagged population. Fish.of less than 11-12 inches i n length are not accepted by the canneries, so any smaller f i s h caught are usually returned to the water by the fishermen. However, as random samples of the catch were taken for tagging some f i s h of l e s s than 290 mm. ( l l inches) were tagged. -44-Pigure 1 shows the length frequencies of f i s h In the Baynes sound region; 290 mm. was taken as representing the dividing l i n e "between those f i s h which would be accepted by the canneries and those which would not. From t h i s figure i t was estimated that 82$ of the f i s h were longer than 290 mm. The catch f o r each period was m u l t i p l i e d by 10.0/82 = 1.22. Figure 2 shows the length frequencies .for the Boat harbour region. Here 84$ of the f i s h were longer than 290 mm. and therefore the catches from t h i s region were mult i p l i e d by 1.19. Table XVI shows the weighting of the tag returns f o r the Boat harbour region. TABLE XVI BOAT HARBOUR  Column 1 Column 2 Column 3 Column 4 Period Tags used Tags recovered F i s h s t i l l Column 1 x to be Column 3 caught  A 425 58 107,502 45,688,350 I - 363 70 100,092 36,333,396 I I 390 89 79,722 39,091,580 I I I — — IV 49 7 11,670 571,830 Totals (Period A included) 1227 224 298,986 113,685,156 Totals (Period A excluded) 802 166 191,484 67,996,806 Boat Harbour Period A included? Total Column 4 113.685.156 _ Q • (Recovery s u s c e p t i b i l i t y Total Column 1 = 1,227 ~ factor) Period A excluded: Total Column 4 '. 67.996.806 _ ft. ftk (Recovery s u s c e p t i b i l i t y Total Column 1 = 802 " factor) Period A included: T o t a l Column 2 x Total Catch " ^  224 x 107.502 _ 2 g Q Recovery s u s c e p t i b i l i t y f a c t o r — 92,683 = Period A excluded: Total Column 2 x Total. Catch — 1<S6 x 107.502 _ 2 1 Q Recovery s u s c e p t i b i l i t y f a c t o r = : 84,784 — Period A included: Adjusted Fishing Intensity: 260 _ 21.2$ 1,227 ~ Period A excluded: Adjusted Fishing Intensity: 210 _ 26.2$ 8"02 -In t h i s area a tagging was c a r r i e d out during the l a s t three days of December,<1945; t h i s i s referre d to as Period A. In weighting the recoveries from this, tagging, the t o t a l catch for the season has been used, as no catch s t a t i s t i c s were available f o r December, 1945. This introduced an error of 5% i n the adjusted f i s h i n g i n t e n s i t y . The r e s u l t s including and excluding t h i s sample are given i n the t a b l e . From Table XV and Table XVI i t w i l l be seen that the adjusted f i s h i n g i n t e n s i t y f o r the Baynes sound and Boat -46-harbour regions are 42.5$ and 26.2$ ( t r i p A excluded) respectively. The corresponding unadjusted percentages are 32.2$ and 20.8$ ( t r i p A excluded). The foregoing has been an analysis of the recoveries made' during the 1946 spawning season. For comparison with these are the recoveries made during the 1947 spawning season i n the Boat harbour region. These returns cover the months of January and February only, as on March 1 the otter trawler fishermen went on s t r i k e . Unfortunately no complete 1947 returns are available for the Baynes sound region as parts of t h i s region were closed to trawlers i n May, 1946. A l l the major f i s h i n g areas with the exception.of cape Lazo were affected by t h i s r u l i n g . In Table XVII and Table XVIII the tag returns ..from January, 1946, to January, 1947,.are shown fo r the Baynes sound and Boat harbour regions r e s p e c t i v e l y . F i s h tagged i n the Boat harbour region were not a l l recaptured i n that area; those returns marked with an asterisk were captured i n other parts of the g u l f . TABLE XVII BAYNES SOUND  T r i p H : 1946* : 1947 No. Jan.Feb.Mar.Apr.May June July Aug.Sep.Oct.Nov.Dec.Jan.Feb. 1 28 27 3 3 2 17 23 4 3 2 3 14 20 8 1 1 4 7 39 10 4 5 5 27 7 3 1 1 6 - 9 4 2 7 — 5 9 4 1 TABLE XVIII BOAT HARBOUR 1955 194? Area and T r i p Jan.Feb.Mar.Apr.May June July Aug.Sep.Oct.Nov.Dec.Jan.Feb. No.  Boat 30 15 3 l p 1* hbr. IA 3p 2A Por-l i e r IA 3b l p IA l p l p 2p 2A 1 l p 8 2 IA IA IA 4A l p IA l p l p 2b Boat 16 12 1 hbr. l p 2A Por- 2b 3p IA 3P H e r l b 2A l p 2p l p IA 1 6 2 2A IA 2p Boat hlar. Por-l i e r 16 IA 11 2p l b IA 2A 2p • 2p IA l p IA. IA. 1 3 2A 5 3 Boat 13 11 1 l p 1 2p i l p 1 2A 1 hbr. IA 2A 2A Por- 3b IA IA IA l i e r 5P l b Boat hbr. 8 11 2A 1 l p l p IA l p 2A 1 l p IA IA 3 2 5 Boat hbr. 30 3 IA 2A IA 2p. l p IA l p l p IA 6 Boat hbr. 1 l p 3A l p IA 2 1 2A KEY: Numbers with no symbol after them are f i s h tagged and recovered i n the Boat harbour areas. p - recovered i n P o r l i e r pass. pasa A - recovered i n an area other than Boat hbr. or P o r l i e r / b - recovered i n Boat hbr., applicable to f i s h tagged at P o r l i e r pass only. -48-During January and February, 1947, 58 tags were recovered i n the Boat harbour region. This represents 6.3$ of the tags remaining unaccounted f o r at that time. During the same period l n 1946, 198 actual recoveries were made. By weighting these returns so that a l l tags appeared to be out at the s t a r t of the f i s h i n g season, the e f f e c t i v e number- of recoveries becomes 230._ This represents 18.8$ of the tags out at the start of the season. Thus there i s a very marked drop i n the 1947 recoveries as compared to the 1946 ones. The following factors account for t h i s drop: 1. Tagging mortality. This factor w i l l reduce the 1946 and 1947 returns by approximately the same amount provided the mortality occurred shortly a f t e r tagging. However, i f some mortality caused by tagging occurred a f t e r March, 1946, then the 1947 returns w i l l be reduced i n comparison with the 1946 returns. A number of tagged f i s h recaptured about t h i s time showed sores produced by the tag chafing. I f these sores lead to the death of many f i s h , then tagging mortality would reduce the 1947 returns as compared to the 1946 returns. 2. Natural mortality. During the short period under consideration i n 1946, the eff e c t of natural mortality w i l l probably be n e g l i g i b l e . However, during the remainder of the year t h i s f a c t o r w i l l not be n e g l i g i b l e and w i l l reduce the percentage of 1947 returns l n comparison to the 1946 returns. This i s probably the most important f a c t o r . 3. F i s h i n g i n t e n s i t y . Provided the f i s h i n g i n t e n s i t y -49-remains unchanged, this factor w i l l not af f e c t t h e percentage returns. However, i f the fishing intensity was less during 1947, then i t w i l l reduce the percentage returns in 1947 as compared to 1946. 4. Failure of f i s h to return to the spawning grounds. If not a l l the fi s h tagged in 1946 returned to the spawning grounds in 1947, the percentage returns in 1947 will.be less than in 1946. This factor should be considered, though at the present time no data i s available on i t . As no adequate estimate can be made, on the basis of the data available, of any of the probable effects of any of these four factors, no attempt has been made to determine the total mortality rate or the fishing mortality rates on the basis of returns for these two years. A very rough determination could be made by plotting the logarithms, of the number of returns made in January and February of each year against the year of return and extrapolating, the line to zero time; however, such an estimate would be too inaccurate to be of any practical value. Growth Rates The data from the 1947 tag returns form a basis, on which an estimate can be made of average annual growth increment of fi s h in the Boat harbour region. Tagged f i s h are measured on tagging and on recovery, and, provided both these are accu-rate, an estimate of the amount of growth can be made. In determining the accuracy of the recovery measurements -50-the criterion used was that, i f a fisherman recorded some of his measurements to an eighth of an inch, then a l l the measure-ments made by him were considered accurate. The recovery lengths in inches were converted to millimeters. The lengths of the lemon sole at time of tagging were plotted against the corresponding lengths at time of recovery, and a straight line f i t t e d to the points by the method of least squares. (Figure 3). From this line the average growth in a year of fi s h between 250 mm. and 425 mm. can be obtained.. This line shows the average amount f i s h between 250 and 425 mnr. increase in length a year. The average of these length increments w i l l represent the average annual length increment of f i s h in the Boat harbour region. This was found to be,23.5 mm.; the range is from 27 mm. for f i s h of 250 mm. to 19 mm. for fish, of 400 mm. If this yearly increment i s expressed as a percentage of the length of the f i s h in 1946, the result i s the average annual percentage growth rate for fish of that length. This varies from 10.8$ for f i s h of 250 mm. to 4.5$ for f i s h of 425 mm. It should be pointed out that the sampling here i s not random in that among the smaller fish, taken for tagging, there i s probably definite selection of individuals which have hitherto grown more rapidly and hence have entered the fishery younger than others in their age classes. How this more rapid early growth affects their subsequent growth history i s not known. Assuming, then, that the mean of the lengths plotted represents the mean length of the f i s h in the population, then the Fig.3. Growth of Lemon Sole. Boat Harbour -51-average annual percentage growth rate at t h i s mean length w i l l be the closest estimate, under the circumstances, of the average annual percentage growth rate of the population. This value i s 7.3$. The annual percentage increase l n length can be converted to the annual percentage Increase i n weight i n the following manner: The approximate r e l a t i o n s h i p between the length of a f i s h and i t s weight i s given by the formula: W » kL 3, where W Is the weight, L l s the length, and k i s a constant, often referred to as the c o e f f i c i e n t of condition or the Ponderal Index. W_ s kLn 3 n Now the length i n year n «• 1 w i l l be: L j ^ = L n r aL n, where a i s the average annual rate of increase i n length. Therefore, weight i n year n .*• 1 w i l l be v W n . 1 = *< Ln * l ' 3 = k K * 3 Ln ( aV * 3I. ntaL n) 2 * <aLn)3j Now the terms containing powers of aLn greater than one are s u f f i c i e n t l y small...to be ignored i n a rough c a l c u l a t i o n . Therefore:, W - k ( L 3 - 3al>h n _ t- 1 n n Now: k L 3 - W_ • ' ' n - n Therefore: w n + 1 = W n *" 3 a ^ n -52-Now, the weight i n the year n * 1 w i l l he the weight i n year n plus annual weight increment. Therefore, _a represents the annual rate of increase i n weight, and so the annual rate of increase i n weight i s roughly three times annual rate of increase i n length. Therefore, the average annual rate of increase i n weight of the lemon sole i n Boat harbour i s 21.9$. Discussion of Fishing I n t e n s i t i e s When the inte n s i t y of a f i s h e r y has been determined the problem arises as to whether t h i s Intensity i s too great to maintain the fis h e r y at i t s present l e v e l of abundance. Is the annual removal of f i s h by a l l causes balanced by the annual recruitment? Or, putting t h i s i n another way, l s the i n t e n s i t y of the f i s h i n g such that the number of mature f i s h l e f t on the grounds annually large enough to produce a s u f f i c i e n t number of young f i s h to balance the annual removal of f i s h at the time when these young f i s h enter the fishery? A secondhand associated problem, also arises, namely, i s t h i s i n t e n s i t y one which w i l l maintain the fishery at i t s most productive level? It has been shown by many workers (Baranov 1918, Russell 1931, Thompson and B e l l 1934, Thompson 1937) that a fi s h e r y may be s t a b i l i z e d at many d i f f e r e n t l e v e l s of y i e l d , but that there i s an optimum y i e l d which takes f u l l advantage of the maximum growth of the population. No r e a l attempt can be made to answer eithe r of these . -53-questionson the basis of the data presented i n t h i s report. To solve these problems, the t o t a l annual mortality rates, the annual recruitment, and the annual growth rate must be known. The estimation of* the annual recruitment and also of the growth rate are best determined from studies of the age d i s t r i b u t i o n s of the population. Such age determinations are outside the scope of t h i s study. Growth rates can, however, be determined from tag returns provided accurate measurements are taken of the lengths of a l l tagged f i s h at the time of recapture, and provided these f i s h were recaptured a f t e r a long enough period to permit an estimate to be made of the annual amount of growth as f i s h do not grow at a constant rate throughout the year. Any estimate of the annual growth rate based on the increase i n lengths shown by f i s h at freedom for l e s s than a f u l l year i s l i a b l e to be inaccurate. T h i r t y - f i v e tags recovered i n Boat harbour i n January and February, 1947, s a t i s f i e d the above conditions, and on t h i s basis the average annual increase i n weight was found to be 21.9$ f o r lemon sole i n that region. The annual seasonal expectation of death (which includes both f i s h i n g and natural mortality rates) can be determined from either the age composition of the population, by the methods used by Baranov (1918), Jackson (1939), or Ricker (1944), or from the returns of tagged f i s h . Methods based on the age composition of the stock are not discussed further because, as has been stated, age determinations are outside the scope of t h i s work. Several methods using tag returns have been evolved: Ricker (1945) gives two methods, the f i r s t based on the tagging of f i s h i n two successive years p r i o r to the st a r t of the f i s h i n g season, and the .comparison of the returns i n the second year from each year's tagging. The s u r v i v a l rate (complement of the mortality rate) equals (year 1 recaptures)(number marked year 2) (year 2 recaptures)(number marked year l ) His second method makes use of f i s h tagged throughout the season instead of just p r i o r to the season. To use t h i s information certain assumptions were made: 1. That the seasonal d i s t r i b u t i o n of marking was the same throughout both seasons. 2. That the t o t a l mortality rates were the same i n both years and the same for the whole of the ranges of sizes studied. 3. That a l l the year's mortality (natural and f i s h i n g ) takes place during the time marking goes on and that the seasonal d i s t r i b u t i o n of mortality of both sorts, parallels'-that of the marking. -Thompson and Herringtbn (1930) and Hart (1943) use a method based on the tagging df f i s h during a season and the analysis of the recoveries made i n successive seasons. They assume that the t o t a l annual mortality rate i s represented by the decline i n actual numbers of returns, each year., provided that the mortality rates and f i s h i n g e f f o r t s are constant from year to year, and that tagged f i s h , a f t e r recovering -55-from the i n i t i a l shock of handling, die at the same rate as the untagged f i s h . Thompson and Herrlngton obtain an estimate of the f i s h i n g mortality rate by extrapolating to zero time the l i n e formed by p l o t t i n g the logarithms of the yearly returns (expressed as a percentage of the tags available at the start of the year) against the years of recovery. Then, by assuming that t h e i r tagging mortality i s n e g l i g i b l e , they calculated the natural mortality from the t o t a l annual m o r t a l i -ty and the f i s h i n g mortality. Hart finds the annual mortality rate from the slope of the l i n e formed by p l o t t i n g the loga-rithm of the tags recovered against the year of recovery. None of the methods outlined above i s suitable f o r c a l c u l a t i n g the mortality rates of lemon sole i n the Baynes sound and Boat harbour regions as tagging was c a r r i e d out for only one year and as complete returns are available f o r one year only. These methods also cannot be applied to determine mortality rates from the tag returns f o r successive two weekly periods because: 1. The mortality rates and f i s h i n g e f f o r t cannot be assumed to be constant from period to period; t h i s i s shown by the v a r i a t i o n i n the total, catch and a v a i l a b i l i t y per period. 2. No information i s available on tagging mortality or the length of time required by lemon sole to recover from the shock of handling. As the periods under consideration occur very shortly a f t e r the time of tagging, the tagged f i s h -56-cannot be assumed to die at the same rate as the untagged f i s h . 3. The number of recoveries per -period are small and i n some cases so nearly equal that the errors introduced through the chance recovery of tags i n any period would d i s -t o r t the r e s u l t s considerably. 4. As neither tagging nor the resampling of the population to obtain recoveries was done at d e f i n i t e regular i n t e r v a l s , Jackson's (1939) method cannot be applied to t h i s data. Unless the f i s h i n g mortality rate, the natural mortality rate, the amount of annual recruitment to the population, and the annual growth rate are a l l known no statement can properly be made about the s t a b i l i t y of a f i s h e r y . As was shown l n the foregoing paragraphs., neither the mortality rates nor the amount of annual recruitment can be determined on the basis of the. data presented. Therefore no v a l i d statement about the s t a b i l i t y of the fishery can be made. However, on the basis of the estimated f i s h i n g i n t e n s i t i e s and the annual rate of increase i n weight calculated, an estimation of the probable state of the f i s h e r y may be made. A f i s h i n g i n t e n s i t y of 26.2$ during the spawning season i s probably too high f o r the Boat harbour f i s h e r y to support and s t i l l maintain an annual recruitment that, together with a growth rate of about 22$, w i l l balance the high t o t a l mortality rate that l s suggested by the comparison of the percentage tag returns (6.3$) obtained i n 1 9 4 7 with the -57-percent age tag returns (18.6$) obtained i n 1946. Assuming that the growth rate i s the same for Baynes sound and Boat harbour lemon sole, a f i s h i n g i n t e n s i t y of 42$ during the spawning season appears too high for the Baynes sound f i s h e r y to support and s t i l l be i n equilibrium. Therefore, the conclusion i s that f i s h i n g i n t e n s i t i e s during the spawning seasons, of 26.2$! and 42.5$, for the Boat harbour and Baynes sound regions respectively, are too high. POPULATION CHANGES r In t h i s section an attempt Is made to determine the amount of population change on the lemon sole spawning grounds of Baynes sound and Boat harbour, that i s , to show whether the spawning population i s stationary or i s continu-ously changing with f i s h a r r i v i n g to spawn and leaving through-out the season. This i s done by r e l a t i n g , f o r each t r i p made i n January and February, the number of tags, out at. the star t of each two weekly period with the number of recoveries and the t o t a l weight of fish.caught during that period. The method used was to express the tag recoveries.from each,tag-ging for each period as i f a f i x e d number.of tags, one hundred, were out at the start of each period, and a fi x e d weight, of f i s h , one hundred thousand pounds.,, were caught i n each period. By expressing the number of recoveries i n t h i s manner, the effect of the varying numbers of tags out and of -58-the d i f f e r i n g catches of f i s h made each period, on the number of tags recovered w i l l be eliminated. The tag recoveries, adjusted In this.manner are shown i n Table XIX and graphically i n Figure 4 f o r the Baynes sound region, and i n Table XX and graphically i n Figure 5 f o r the Boat harbour region. TABLE XIX BAYNES SOUND No. & Number and Date of T r i p Date of Period I Jan. 4 II Jan.12 I I I Jan.18 IV Jan.24 V Jan.28 VI Feb.13 VII Feb.23 I Jan. 1-15 23.I 36.0 ( — — II Jan.16-28 23.5 25.4 25.5 21.5 33.3 _ III Feb. 1-15 26.0 24.1 21.9 32.2 15.7 IV Feb.16-28 18.7 28.5 13.6 30.0 27.6 39.4 25,3 V Mar. 1-15 4.4 9.9 15.6 21.1 11.7 30.6 23.2 VI Mar.16-31 3 - 1 4.6 3.1 3.9 6.8 ' B A K N E S S O U N D X PERIODS g.4. Baynes"Sound. E f f e c t i v e Tag Recoveries from each Trip A v a i l a b i l i t y . Total Catch. -59-TABLE XX  BOAT HARBOUR No. & Number and Date of T r i p Date of Period A Dec.28 I Jan.7 II Jan.15 I I I Jan.20 IV Jan.26 V Jan.30 VI Feb.16 I Jan. 1-15 8.1 II Jan.16-31 23.9 38.2 40.9 41.1 68.9 III Feb. 1-15 6.5 15.5 16.8 20.5 17.5 43.6 - — -IV Feb.16-28 9.7 • 6.5 12.4 25.9 10.3 34.0 22.1 V Mar. 1-15 117.5 212.5 — 235.0 517.0 505.3 VI Mar.16-31 71.0 38.7 51.6 64.5 77.4 432.3 In i n t e r p r e t i n g these r e s u l t s the following assumptions are made: 1. The tagged f i s h do not school, and are d i s t r i b u t e d equally amongst the untagged population. 2. Tagging mortality i s n e g l i g i b l e or a f f e c t s the f i s h tagged on each t r i p i n p r e c i s e l y the same manner. - -3« Natural mortality, during the period under considera-t i o n i s n i l . 4. The loss of tags aft e r recapture and before return either a f f e c t s the recoveries from each t r i p f o r each period i n the same manner or i s n i l . Before the r e s u l t s given i n the tables are discussed, certain t h e o r e t i c a l interpretations of such r e s u l t s are considered: -6o-1. I f no immigration or emigration - takes place, that Is, i f the population i s absolutely stationary, then the e f f e c t i v e returns per period (that, i s to say, the actual returns adjus-ted as i f one hundred tags had been out at the star t of the period and one hundred thousand pounds of f i s h had been caught during the period) would remain constant. 2. Again, i f emigration alone took place, and, providing the tagged f i s h were equally d i s t r i b u t e d throughout the population, then the e f f e c t i v e return per period w i l l again be constant, for tagged and untagged f i s h should leave the grounds at the same r a t e . In such a case.fish are becoming less abundant on the grounds and t h i s w i l l be r e f l e c t e d i n the lower average catch per hour f o r that period. 3. I f immigration alone occurs during any period, then the e f f e c t i v e returns for that period w i l l show a decline. This i s because the immigrants have lowered the r a t i o of tagged to untagged f i s h present on the ground, that i s , the population has been d i l u t e d . In t h i s case more f i s h , w i l l be present on the grounds and the average catch per hour for that period should show an increase. 4. I f Immigration and emigration take place at, the. same time the ef f e c t i v e returns per period w i l l drop. There are three possible ways i n which emigration and immigration could occur together: 1. I f emigration exceeds immigration. In / t h i s case the e f f e c t i v e returns i n a period would show a de-crease as there would be some d i l u t i o n of tags remaining on -61- • the grounds, and the average catch per period would also show a decrease, as there would be less f i s h on the grounds. 2. When emigration equals, immigration. Here the e f f e c t i v e returns i n a period would again show a de-crease, for d i l u t i o n of the stock i s taking p l a c e ; the average catch per period should remain constant.. 3» I f Immigration exceeds, emigration. The eff e c t i v e returns in. a perio.d would s t i l l show a decrease, but the average catch per period would showman increase. Thus these three possible combinatlonsuof immigration and emigration can be separated by t h e i r e f f e c t on the average catch per hour for a period. ... I t w i l l be noticed, however, that type (3) produces the same e f f e c t as immigration alone. These two may prove d i f -f i c u l t to separate, but some clue to which i t i s may be given by the actual number of.returns for that period, f o r i f any emigration took place the actual number of returns might be less than had no emigration taken place. 5. The above four situations have been considered on the assumption that there was no resident or temporary non-migratory population present. Assume now that there i s such a resident population present. Now, i f the proportion of tag-ged to untagged f i s h i n t h i s resident population was the same as that i n the migratory population, the changes produced by emigration, immigration, or various combinations of them, would be similar to those discussed i n points 1 - 4 . But, « 6 2 -i f i t so happened that the proportion of tagged f i s h i n the resident population was less than that l n the migratory popu-l a t i o n , then any change i n the population due either to immi-gration or emigration, would, cause a drop i n the ef f e c t i v e number of tags recovered. In t h i s case i t would be d i f f i c u l t to separate a case where emigration alone occurred from a case where emigration and immigration both occurred, with emigra- . t l o h exceeding immigration, and also a case where immigration alone occurred from a case where emigration and immigration tpok place with immigration exceeding emigration. 6. Movement of f i s h about the spawning grounds. Consi-deration should also be given to a case l n which the factors involved produce an increase i n the e f f e c t i v e number of returns i n a period. , Assume that the region under consideration i s made up of a number of areas, and. that the fish., f or some reason, tend to concentrate more i n c e r t a i n areas, than i n others, but that i n the tagging operation, the same number of tags were put out i n each area. The r e s u l t of such tagging operations w i l l be that the r a t i o of tagged to untagged f i s h w i l l be greater i n those areas i n which the f i s h are less con-centrated. I f such a region i s f i s h e d commercially., the f i s h -ing w i l l tend to be concentrated i n those areas where f i s h are most abundant, therefore more f i s h w i l l be caught i n those areas i n which tags are r e l a t i v e l y l e s s concentrated. Now, l f f i s h migrate from those areas In which tags are more con-centrated, to those areas i n which the tagged f i s h are r e l a t i v e -l y less concentrated, then the r e l a t i v e concentration of tagged f i s h i n these l a t t e r areas w i l l be increased, and, therefore, on the assumption that the greater part of the catch i n any period w i l l be made i n these areas, the e f f e c t i v e number of returns for a period w i l l show an increase. To prove that such an e f f e c t was produced by migration of t h i s "type, catch s t a t i s t i c s f o r each area as well as for the whole region, would have to be available. To i l l u s t r a t e the e f f e c t s of such migrations a hypothetical example i s given belowj Assume that 40 f i s h were tagged i n each of four areas A, B, C, D, and that the following pattern of tag returns was obtained: Irea of Pageing Area of Recovery A B 0 D k 2 2 0 0 3 2 6 0 0 i J 1 1 2 0 ) 0 2 1 2 Let the catches i n each area i n the same period- be: A = 10,000 l b s . B - 25,000 l b s . C s 2,000 l b s . D m 1,000 l b s . Now, migration has taken place between the various areas, and hence the catch i n an area w i l l be made up of f i s h from that area and of f i s h which have migrated into i t , i n the proportions indicated by the tag returns. Therefore: For area A: Catch = 10,000 = 2a 4- 2b » c 40 For area B: Catch • 25,000 = 2a » 6b » c » 2d 4"o For area C: Catch - 2,000 = 2c » d 40 -64-For area DJ Catch = 1,000 s 2d 40* where a, b, c,*and d, represent the population of each area respectively. Solving the above equations, the populations i n each area ares Area As- 45,000;; Bs- 140,000; Cs- 30,000;: Ds- 20,000. Now, i f no migration takes place, r a t i o Tags returned F i s h tagged, but, i f there has been migration Catch = Population from areas where tagged f i s h are r e l a t i v e l y more concentrated into an area where tagged f i s h were r e l a t i v e l y less concen-trated, then the r a t i o of Tags returned w i l l be greater than Catch the r a t i o F i s h tagged l n those areas into which the f i s h Population migrated. These two sets of r a t i o s f o r t h i s hypothetical population are shown i n the table below: Tags Returned x 10^ Fish Tagged x 10^ Catch Population A 50 9 B 44 29 C 60 133 D 200 200 Thus, this example i l l u s t r a t e s that the migration of f i s h from an area where tagged f i s h are more concentrated to an area where they are l e s s concentrated and where more f i s h i n g i s done, raises the e f f e c t i v e number of returns. The foregoing t h e o r e t i c a l considerations form a back-ground against which the variations; i n the e f f e c t i v e tag -65-returns f o r each period i n the Baynes sound and Boat harbour regions can be p a r t i a l l y interpreted. The v a r i a t i o n s . i n e f f e c -t i v e returns per period for each tagging should give an i n d i -cation of the population changes occurring on each of the spawning grounds. Each region w i l l now be considered separately: 1. The Baynes sound region. For t h i s region the e f f e c t i v e returns f o r each t r i p ' s tagging, obtained by the method described, are given i n Table X I X , page 58, and Figure 4, following page 58. 1. For any t r i p , the e f f e c t i v e returns f o r the period during which the t r i p was made are not r e l i a b l e . This i s because the tagging was done, not at the s t a r t of the period, but at some, time during i t , and therefore, i n adjusting for the amount of f i s h caught, a proportion of the catch for the period corresponding to the f r a c t i o n of the period from the time of tagging to the end of the period had to be used. Such a pro-portion may not correspond accurately to the r e a l weight of f i s h taken during that time and so w i l l d i s t o r t the results:. 2. In the f i r s t four periods there appears to be considerable variation i n the trends shown by the ef f e c t i v e returns from the various tagging operations. However, i n the l a s t two periods, a l l the returns show a sharp decline. During these same txfo periods the a v a i l a b i l i t y also decreases sharply. In the discussion of the t h e o r e t i c a l aspects of t h i s problem i t was shown that three types of population change w i l l -66-produce a decline In e f f e c t i v e returns associated with a decline i n a v a i l a b i l i t y . These are; a. a greater emigration than immigration taking place from a population i n which only the migratory or spawning f i s h were tagged, and b. either emigration alone, or c. a greater emigration than immigration taking place from a population i n which a resident or temporarily non-migratory population received a small proportion of tags. The changes i n the Baynes sound population during periods V and VI can probably best be described by either of the l a s t two assump-tions, the second being the more l i k e l y one. 3 . In view of the fact that increases i n the e f f e c t i v e numbers of returns f o r a period are produced by migration of f i s h fro'm areas with a higher concentration of tagged f i s h to areas with a lower concentration, or (as the approximately same number of tags were put out i n each area) from an area with r e l a t i v e l y fewer f i s h to an area where more f i s h are present; the increases noted i n the e f f e c t i v e returns for t r i p I during period I I I , for t r i p s I I and V during period IV, and for t r i p I II during period V, are of in t e r e s t , especially as these increases occurred i n periods immediately preceding the start of the sharp decline i n returns. I t has been shown (Table V, page 20) that the y i e l d s of f i s h per hour's dragging are greatest i n the Deep and Fanny bay areas and further that there was a d e f i n i t e movement of f i s h from both ends of Baynes sound -67-towards the Fanny bay area (Table VII, page 25). Therefore the Increase l n e f f e c t i v e returns noted for these t r i p s i s possibly the re s u l t of a migration to and accumulation of f i s h i n , the Fanny and Deep bay areas p r i o r to t h e i r leaving the spawning grounds. 4. The fact that the ef f e c t i v e returns for t r i p I started to decline sharply a period before the returns f o r other t r i p s would indicate that some of the lemon sole tagged e a r l i e r i n the season are leaving the grounds before those tagged l a t e r i n the season. The conclusion i s that the population of lemon sole present i n Baynes sound during January, February, and March consisted of a small resident population as well as a much larger migratory spawning population. The evidence points to general emigration of lemon sole from t h i s region s t a r t i n g about the end of February. There i s some evidence that emi-gration may have started about the middle of February and that these early emigrants are f i s h that were present on the grounds e a r l i e r i n the season. There was also some i n d i c a t i o n of a migration to and accumulation of f i s h i n the Deep and Fanny bays p r i o r to leaving the spawning grounds. 2. The Boat harbour region. For t h i s region the ef f e c t i v e returns for each t r i p " s tagging, calculated i n the same manner described e a r l i e r are shown i n Table XX, page 59, and Figure 5, following page 58. 1. The same reservations as. were made f o r the Baynes sound -68-reglon must be made here concerning the e f f e c t i v e returns from a t r i p f o r the period during which the tagging was.done. The returns for t r i p A f o r period I, for t r i p s I and II for period I I , and for t r i p V i n period III can be considered r e l i a b l e , as i n each case the tagging was done before the commencement of the period i n question. 2, Large increases w i l l be noticed i n the e f f e c t i v e returns for t r i p s A, I, IV, V, and VI during period V. In period VI the e f f e c t i v e returns for t r i p s A, I, I I I , IV, V, and VI were s t i l l comparatively large but showed a considerable de-crease over those for period V. In periods V and VI the t o t a l catches made were small, being l e s s than l/20 and l / l O respec-t i v e l y of the catch made i n period IV, Therefore i n weighting the tag returns for these two periods the adjusted or e f f e c -t i v e returns w i l l be disproportionately large when compared with those of other periods. In the Baynes sound region increases i n eff e c t i v e returns were explained on the basis of a migration of f i s h between areas; such an explanation cannot be applied i n t h i s case as the actual returns of tags are too small to indicate a migration of the si z e necessary to produce such large Increases In eff e c t i v e returns. There-fore the weighting of the returns by the disproportionately small catches made i n these periods alone caused t h i s marked increase i n effe c t i v e returns. 3. The v a r i a t i o n i n e f f e c t i v e returns.from the various tag-gings indicate that a part of the population emigrated from the region during period III and that i n the succeeding periods more of the population emigrated so that by period VI most-of the migratory spawning population had probably l e f t the grounds. I t w i l l be noticed that the e f f e c t i v e returns f o r t r i p s I and I I decreased from approximately 40 l n period II to 20 i n period I I I , while the e f f e c t i v e returns for t r i p V i n period III were s t i l l above 40. That i s to say, that, during period II from February 1 to 15, the number of e f f e c t i v e returns from f i s h tagged up u n t i l January 15 decreased, as compared to the number of e f f e c t i v e returns of f i s h tagged on January 30. During periods II and I I I the average catch per hour declined. Now, the considerations of th e o r e t i c a l p o s s i b i l i t i e s of v a r i a t i o n l n e f f e c t i v e returns showed that, for a decline i n e f f e c t i v e returns to be associated with a decline l n average catch per hour, the assumptions had to be made either that emigration exceeded immigration or that, i f emigration alone was occurring, a small proportion of f i s h tagged were from a resident or temporarily non-migratory population. I f the f i r s t assumption were applicable 0, the expected number of e f f e c t i v e returns from f i s h tagged on January 30 would be les s than the number of e f f e c t i v e returns for f i s h tagged p r i o r to January 15 and recaptured during period I I , due to the d i l u t i o n of tagged f i s h r e s u l t i n g from the assumed emigration. However, as this was not so, the second assumption would appear to f i t the case more nearly, that i s , that some of the f i s h tagged p r i o r to January 15 -70-remained on the spawning grounds during the period from February 1 to 15, whilst others emigrated. The effective returns for t r i p s I, I I , IV, and V declined again during period IV, that i s , from February 16 to 28, and the average catch per hour declined sharply during t h i s same time. This would again Indicate that only a'part of the population emi-grated at t h i s time. The e f f e c t i v e returns during periods V and VI do not lend themselves to in t e r p r e t a t i o n because of the d i s t o r t i o n i n weighting introduced by the very small catches made i n these periods. The conclusion i s that, i n the Boat harbour region, the lemon sole d i d not leave the spawning ground en masse at one time but f i s h were continuously emigrating from the grounds during February and March. The very low average catch per hour i n periods V and VI would indicate that the emigration of the spawning population was probably concluded by March. DISPERSAL OF LEMON SOLE FROM THE SPAWNING GROUNDS The populations of lemon sole found on the spawning grounds i n Baynes sound and Boat harbour regions are la r g e l y non-resident spawning populations. Reports received from the commercial fishermen indicate that the f i s h s t a r t to ar r i v e on these grounds i n numbers about December and to leave i n February and March; and that i t i s only during t h i s period that good catches are made. These reports are borne out by the variatio n s i n the -71-abundance (average catch per hour f o r each period) of lemon sole as calculated from p i l o t house log book records. In both the Baynes sound and Boat harbour regions the average catch per hour drops sharply towards the end of February. Therefore one reason for tagging lemon sole on these two spawning grounds was to obtain information as to the extent of dispersal of the f i s h following spawning. The points of recovery of tagged f i s h would indicate t h i s , and would also show i f there was an appreciable Intermingling of the popula-tions spawning on the two grounds. In the Baynes sound region 814 f i s h were tagged. To date, no tags have d e f i n i t e l y been recovered from areas outside t h i s region. Two tags have been reported as probably having been caught i n Nanoose bay, however, considerable doubt exists as to the r e a l point of recapture of these tags. The fact that none 1of the f i s h tagged l n Baynes sound have been recovered from points outside t h i s area cannot be taken as i n d i c a t i n g that the population i s non-migratory, for the marked decline i n average catch per hour observed during March d e f i n i t e l y Indicates that the f i s h are leaving the grounds. Further, the absence of a d e f i n i t e summer fis h e r y i n Baynes sound indicates that there must be, at the best, only a small resident population i n t h i s region. Therefore, these f i s h probably disperse to those parts of the gulf of Georgia from the Nanoose bay region northward, that i s , to areas not often fished by the otter trawlers. -72-In the Boat harbour region 106 recoveries out of a t o t a l of 359 were made i n areas outside the region of tagging. These recoveries are shown i n Table XXI. From t h i s table i t w i l l be noticed that: 1. There i s a d e f i n i t e migration of lemon sole i n both directions between P o r l i e r pass and the Boat harbour region. The comparatively large number of returns from.Porlier pass during August and September, 1947, might indicate that the l e -mon sole were moving through the Porlier.pass region on the way back to spawning grounds. Mr. G. B. Shannon, an experi-enced trawl fisherman, reports that lemon sole appear i n numbers i n the P o r l i e r pass area i n September, and that a month l a t e r they are to be found about six miles northward. He has also found a s i m i l a r southward migration taking place i n February and March. 2. From the B 0at harbour spawning ground, there i s a general southward dispersion of lemon sole, extending as f a r as the mouth of the Fraser r i v e r and the Bellingham bey-point Roberts area. The fact that no f i s h tagged i n the Baynes sound region were recovered to the south i n the Boat harbour region and that no f i s h tagged i n Boat harbour were recovered to the north i n the Baynes sound region would indicate that the population using these two spawning grounds are separate and do not intermingle to any extent. TABLE XXI • ; BOAT' HARBOUR 1946 Number of Recoveries per Month 1947 JanFebMarAprMayJunJulAugSepO otNovDe cJan Area of Recovery Area of Total Tagging Date of Tagging P o r l i e r pass Yellow point 2 1 4 3 1 1 9 6 1 2 3 33 Boat harbour Jan-Feb/46 2 1 10 15 Boat hbr,Porlier pass Dec/45-Feb/46 Ladysmith 1 5 1 3 2 12 Boat hbr,Porlier pass Dec/45-Jan/46 Ghemalnus 5 1 l l ' 1 1 10 Boat hbr,Porlier pass Dec/45-Jan/46 Thetis i s l a n d (west side) 2 1 1 1 5 Boat harbour Dec/45-Jan/46 Active pass 1 1 2 Boat hbr,Porlier pass Dec/45-Jan/46 S a t e l l i t e ch. 1 1 Boat harbour Jan/46 Swanson ch. 1 1 1 3 Boat harbour Dec/45-Jan/46 Beaver point 2 2 Boat harbour J an-Feb/46 Pender i s l a n d 1 1 Boat harbour Jan/46 Captains pass. 1 1 Boat harbour Jan/46 Fraser r i v e r 1 2 3 Boat harbour Dec/45 Pt. Roberts reef 1 1 2 Boat hbr,Porlier pass Dec/45-Jan/46 Be11Ingham bay 1 1 Boat harbour Jan/46 G-abriola pass 1 6 7 Boat harbour Dec/45-Jan/46 Boat harbour 4 4 • "... 8 .Porlier'pass Jan/46 I f the fishery f o r the spawning lemon sole i n the Baynes sound and B 0 a t harbour regions l s too intense and i s producing a decline i n the abundance of lemon sole i n these areas, t h i s decline w i l l be reflected- i n a l l areas to which the f i s h disperse af t e r spawning. However, l f the f i s h frequenting the Baynes sound and Boat harbour spawning grounds are separate populations which do not intermingle extensively, then a too intense f i s h e r y on one of these grounds w i l l bring about a reduction of f i s h only i n those parts of the gulf normally supplied by t h i s spawning ground. For instance, the f i s h i n g i n t e n s i t y i n the Baynes sound region appears to be rather too high to maintain the stock at i t s present l e v e l of abundance. This should not cause a general depletion of lemon sole throughout the gulf but only i n that part of i t from Nanoose bay northward, provided the assumption i s correct that t h i s i s the area over which the Baynes sound f i s h disperse after spawning. POPULATION DIFFERENCES As was mentioned i n the previous section the returns of tagged f i s h Indicated: 1. That the lemon sole found on the Baynes sound and Boat harbour spawning grounds came from two separate populations which did not intermingle appreciably. 2. That the f i s h i n g i n t e n s i t y was considerably higher in. the Baynes sound region than i n the Boat harbour region. -75-To see whether these two factors had produced any major differences i n the composition of the populations i n these regions, the length frequency d i s t r i b u t i o n , the sex r a t i o , and the r a t i o of immature to mature f i s h , were determined for each region. P o r l i e r pass was treated separately. The t o t a l numbers of mature and immature males and females and the percentage each represents of the t o t a l population of the region are shown i n Table XXII. Figure 6 shows the length frequency d i s t r i b u t i o n f o r immature males and females for the Baynes sound region, Figure 1 for the Boat harbour region, and Figure 8 for the P o r l i e r pass region. TABLE XXII Immature Immature Mature Mature Sex Ratio Males Females Males Females Mature F i s h No. f> No. % No. % No. % Males Females Baynes sound 44 2.4 396 21.9 411 22.7 959 53.0 30^ 70% Boat harbour 31 2.2 42 2.9 476 33.1 889 61.8 35% 65£ P o r l i e r pass 6 2.7 151 67.4 0 0 67 29.9 0% 100$ From an examination of Table XXII and Figures 6, 7, and 8, i t appears that; 1. The length frequency d i s t r i b u t i o n s of the mature males and females are very similar i n the Baynes sound and Boat harbour regions. There are more small mature females (of 300 mm. or less i n length) i n the Baynes sound region. 2. In the Baynes sound region a d e f i n i t e population of 125 B A Y N E S S O U N D I M M A T U R E F E M A L E — — • M A T U R E M A L E 200 250 300 350 400 450 500 LENGTH IN MILLIMETERS Fig.6.Length Frequencies: Immature & Mature Males. & Females Baynes Sound. 125 BOAT HARBOUR MATURE FEMALE ^ 1 1 1 1 1 1 200 250 3 0 0 • 350 4 0 0 450 500 I L L M C T H I N M I L L I M E T E R S .' Fig.7. Length Frequencies: Immature & Mature F i s h . (Males and Females) Boat Harbour, PORLIER PASS . — I M M A T U R E F E M A L E S — MATURE FEMALES 100- IMMATURE MALES FREQUENCY o> o / / / t / / H — ; 1 \ \ \ » % \ \ U — . , » 1 U—; H • 1   ' 200 250 300 350 400 450 500 L E N G T H IN M I L L I M E T E R S Fig.8. Length Frequencies. Immature & Mature Females Immature Males. No Mature Males F&ural. P o r l i e r Pass* -76-immature females was found. It comprised 22$ of the t o t a l population of t h i s area. 3. Immature males formed 2$ 0f the t o t a l population i n both areas. 4. The sex r a t i o , based on the number of mature f i s h , was'approximately the same i n both regions. 32$ of the mature f i s h i n Baynes sound were males and 35$ In Boat harbour. 5. In P o r l i e r pass immature females formed 67$ of the t o t a l population and mature females 32$. No mature males were found. In summary, the Baynes sound and Boat harbour populations have important features of resemblance especially among the mature f i s h . They d i f f e r i n the large (22$). proportion of Immature females present i n Baynes. sound and the greater number of small mature f i s h there. P o r l i e r pass d i f f e r s markedly from the other areas, consisting of two-thirds Immature females. STOMACH ANALYSIS A q u a l i t a t i v e analysis of the stomach contents of lemon sole was made i n the course of the study of the spawning of these f i s h i n the Baynes sound and Boat harbour-Porlier pass regions. The following tables show the r e s u l t s of the stomach analyses f o r these regions: Table XXIII f o r the Baynes sound region, Table XXIV for the Boat harbour areas, and Table XXV for the P o r l i e r pass area. TABLE XXIII BAYNES SOUND FEMALE MALE $ STOMACH Imma- Matur- Eggs Eggs Running Spent To- Imma- Running To-CONTENTS ture ing not c l e a r - t a l ture t a l c l e a r Empty 164 28 173 6 7 60 63 555 29 190 219 Worms 30 6 24 4 18 ^82 4 13 17 78$ Clams 8 2 4 1 11 26 2 4 6 46$ Worms,clams 13 2 18 3 23 59 ,4 2 6 • Worms,clams, b r l t t l e s t a r 1 1 1 3 0 Worms, b r l t t l e s t a r 1 1 1 3 1 1 Clams, b r l t t l e s t a r 1 ... 1 0 B r l t t l e s t a r 0 1 1 4$ U n i d e n t i f i a b l e 1 1 . . 5 1 8 1 1 Miscellaneous 1 1 2 4 2 2 arnpty: 67. 60 63 Observed No.(x) 164 28 173 . 555 29 190 219 Expected No.(m) 164.03 29.21 170.03 57.67 45.69 88.38 34.62 184.38 F u l l : Observed No. (x) . 5 5 11 5* ... 10 1 .55 186 11 23 34 Expected No.(m) 54.97 9.79 56.98 19.33 15.31 29.62 5.38 28.62 Total 219 39 227 77 61 118 741 40 213 253 d (x-m) - .03 -1.21 • 1-2.98 •1-9.33 1-14.31 -25-38 -5.62 1-5.62 *.03 ••1.21 -2.98 -9.33 -14.31 +•25.38 +•5.62 -5.62 d 2 .0009 1.4641 8.8804 87.0489 204.7761 644.1444 31.5844 31.5844 dVm: Empty 0 0.0501 0.0522 1.5094 4.4819 7.2884 0.9123 0.1713 F u l l 0 0.1476 0.1559 4.5633 13.3753 21.7469 5.8707 1.1036 Total 0 0.1997 0.2081 6.0127 17.8572 29.0353 6.7830 1.2749 Females: chi-squared = 53.3130 Males: chi-squared s 8.0579 df - 5 d f = 1 P i s l e s s than .01 P i s less than .01 TABLE XXIV BOAT HARBOUR FEMALE MALE STOMACH Immature Matur- Eggs Eggs Running Spent To- Imma- Running To- % CONTENTS ing not clear t a l ture t a l clear Empty 57 4 170 159 124 31 5^ 5 33 293 326 Worms 14' 4 26 1 1 5 53 2 ^9 11 58$ Clams 2 1 3 2 3 5 20$ Worms,clams 5 5 5 15 1 3 4 Worms,clams, b r l t t l e s t a r 10 1 12 2 2 27 0 Worms, 36 b r l t t l e s t a r 14 17 1 4 1 1 Clams, b r l t t l e s t a r 5 1 6 0 B r l t t l e s t a r l 3 4 3 2 5 32$ U n i d e n t i f i a b l e l 1 0 Miscellaneous 2 3 5 2 1 3 Empty; 124 545 326 Observed No,(x) 57 4. 170 159 31 33 293 Expected No.(m) 87.29 7.08 187.17 128.19 96.30 36.96 40.41 285.59 F u l l : 16 Observed No.(x) 54 5 68 4 1 148 11 18 29 Expected No.(m) 23.71 1.92 50.83 34.81 26.70 10.04 3.59 25.41 Total 111 9 238 163 125 47 693 kk 311 , 355 d (x-m) -30.29 -3.08 -17.17 ••30.81 +•25.70 -5.96 -7.41 H-7.41 +•30.29 4-3.08 4-17.17 4-30.81 -25.70 ••5.96 +7.41 -7.41 917.4841 9.4864 294.8089 949.2561 660.4900 35.5216 54.9081 • 54.9081 dvm; Empty 10.5107 1.3399 1.5751 7.4051 6.7191 0.9611 «i;3588 0.1923 F u l l 38.6961 4.9408 5.7999 27.2696 24.7375 3.5380 15.2947 2.1609 Total 49.2068 6.2807 7.3750 34.6747 31.4566 4.4991 16.6535 2.3532 Females: chi-squared = 133.4929 Males: chl-squared - 19.1067 df r 5 df . . a 1 P i s l e s s than .01 P i s less than .01 TABLE XXV PORLIER PASS FEMALE MALE STOMACH CONTENTS Imma-ture Matur-ing Eggs not clear Eggs Run- Spent cl e a r ning Total Imma- Run-ture ning T o t a l $ "6T 20 1 11 15 12 3 1 1 2 Empty 43 Worms 11 Clams 1 Worms, clams 5 Worms, clams, b r l t t l e s t a r 8 Worms, B r l t t l e s t a r 10 Clams, b r l t t l e s t a r 3 B r l t t l e s t a r U n i d e n t i f i a b l e 1 Miscellaneous 2 4 2 11 5 4 6 1 3 2 0 0 0 0 0 0 0 0 0 45$ 47$ , Empty: Observed No.(x) Expected No.(m) 43 40.35 4 3.36 11 13.45 0 0 3 3.84 61 0 0 0 F u l l : Observed No.(x) Expected No.(m) 41 43.65 3 3.64 17 14.55 0 0 5 4.16 66 0 0 0 Total 84 7 28 0 0 8 127 0 0 0 d Ix-m) ••2.65 -2.65 +•0.64 -0.64 -2.45 +•2.45 -0.84 ••0.84 d 2 7.0225 0.4096 6.0025 0.7056 d^/m: Empty F u l l 0.1740 0.1609 0.1219 0.1125 0.4463 0.4125 0.1836 0.1696 0.9258 0.8555 Tota l 0.3349 0.2344 0.8588 0.3532 1.78F? VO I Females: chi-squared = 1.7813 df . = 5 P i s between .70 and .50 Males: n i l -80-In these tables, columns 1 - 6 , 8, and 9, show the numbers of empty stomachs and the types of food found i n f u l l stomachs of f i s h at the various stages of sexual maturity; columns 7 and 10 give the t o t a l s f o r females and males respec-t i v e l y ; and column 11 the percentage of f u l l stomachs con-taining each of the three main types of food. From these tables i t w i l l be observed that! 1. In the Baynes sound and Boat harbour regions approxi-mately 75$ of the stomachs examined were empty, while i n the P o r l i e r pass area only 51$ were empty. I t should be pointed out that i n t h i s l a s t area the f i s h found were la r g e l y immature and spent females. 2. During the winter months, at le a s t , the food of the lemon sole consists mainly of worms, clams., and b r i t t l e -stars. . The worms were a species of Polychaete, but were not i d e n t i f i e d further. These worms formed the predominant food i n a l l three regions. Small whole clams were found i n the stomachs of many f i s h , while i n others only clam siphons occurred. B r i t t l e s t a r s were found i n many of the stomachs of those f i s h from the more southern parts of the gulf i n which area they were found more frequently than clams. 3. As f u l l sexual maturity was reached these f i s h , especially the females ceased to feed and continued to fas t t i l l spawning was completed. Of the stomachs of 414 immature and 173 spent females examined 150 and 76 respectively were f u l l , while only 2 out of 185 stomachs of f u l l y matured or running females contained any food. -81-To determine whether the differences observed i n the numbers of f u l l and empty stomachs found between f i s h at the various stages of sexual maturity were s i g n i f i c a n t , c h i -squared tests were applied to the data f o r females shown i n these tables. In each case the P value obtained was l e s s than .01 (with the exception of f i s h l n P o r l i e r pass). In order to be sure that any d i s t o r t i o n s produced by having only small numbers of f i s h represented at c e r t a i n stages of maturity were not unduly influencing the significance of the r e s u l t s , the females were divided into three groups, Immature, mature, and spent females, and the chi-squared tests again applied. (Tables XXVI and XXVII). F i s h i n sexual categories I - III were classed as "immature, those i n categories IV and V as mature, those l n category VI as spent. The P values obtained were again considerably l e s s than .01. This would indicate that the differences i n the numbers of f u l l and empty stomachs found as maturity was reached were s i g n i f i c a n t and not due to chance selection of the f i s h . This l a s t t e s t was applied to f i s h from the Baynes sound and Boat harbour regions only. It could not be applied to f i s h from P o r l i e r pass as no f u l l y matured females were found there. Similar tests were applied to the data f o r males i n the Baynes sound and Boat harbour regions. It was again demonstrated that the f u l l y matured f i s h feed less a c t i v e l y than the immature f i s h . However, food was found i n only 13$ of the stomachs of males i n the Baynes sound region and i n only 8$ of those In the Boat harbour region. TABLE XXVI BAYNES SOUND Immature Mature Spent Total Empty: Observed No.(x) Expected No.(m) 365 363.26 127 103.36 63 88.38 555 F u l l : Observed No.(x) Expected No.(m) 120 121.74 11 34.64 55 29.62 186 Total 485 138 118 741 d 4-1.74 -1.74 4.23.64 -23.64 -25.38 4-25.38 d- 3.0276 558.8496 644.1444 dVm: Empty F u l l T otal 0.0083 0.0249 0.0332 5.4068 16.1331 21.5399 7.2884 21.7469 29.0353 12.7035 37.9049 50.6084 chi-squared = 50.6034; df - 2; P i s less than .01 TABLE XXVII BOAT HARBOUR Immature Mature Spent Total Empty: Observed No.(x) Expected No', (m) 173 204.37 283 246.28 28 33.35 484 F u l l : Observed No.(x) Expected No.(m) 66 34.63 5 41.72 11 5.65. 82 Total 239 288 39 566 d -31.37 4-31.37 r36.72 13^8.3584 -5.35 4-5.35 d 2 984.0769 28.6225 d*/m: Empty F u l l Total 4.8152 28.4169 33.2321 5.4749 32.3192 37.7941 0.8582 5.0659 5.9241 11.1483 65.8020 76.9503 chi-squared « 76.9503; df = 2; P i s less than .01 -83-Frora the foregoing i t appears that: 1. Lemon sole do not feed very a c t i v e l y during the winter. This i s shown by the large proportion of empty stomachs found. 2. F u l l y matured f i s h feed 'less a c t i v e l y than immature or spent Individuals. 3. The main food of the iemon sole on or near the spawning grounds were worms, clams, and b r i t t l e s t a r s . Worms were the predominant food i n both regions, clams ranked second i n the more northern area, and b r i t t l e s t a r s i n the more'southern. SUMMARY 1. The fishery for lemon sole i s one of the most important winter f i s h e r i e s i n the g u l f of Georgia. 2. This fishery i s dependent upon populations of lemon sole spawning i n the Baynes sound and Boat harbour regions. The fact that 80$ of the t o t a l landings of lemon sole.for the f i r s t three months of 1946 came from these two regions shows t h i s . 3. The Baynes sound and Boat harbour regions, are shown to be the two major lemon sole spawning grounds i n the gulf of Georgia. A t h i r d small spawning ground l i e s off point Atkinson. 4. In both regions spawning took place from January through to March; the peak period was from approximately -84-January 24 to February 23 In the Baynes sound region and from January 15 to the middle of February i n the B o a t harbour region. The number of samples taken i n February and March was not large enough to permit very accurate l i m i t s to be set to the end of the spawning period i n either region. 5. Active spawning was found to be more intense i n certain areas of each region than i n others, although some spawning took place generally throughout the whole of both regions. The areas of Fanny bay and cape Lazo were found to be the areas of most active spawning i n the Baynes sound region, while the areas of Boat harbour, centre drag, and De Courcy is l a n d formed the areas of most active spawning i n the Boat harbour region. No evidence that spawning took place was found for P o r l i e r pass. 6. The f i s h i n g I n t e n s i t i e s i n the Baynes sound and Boat harbour regions were found to be 42$ and 26.3$ respec-t i v e l y f o r January, February, and March, 1946. These were calculated from the tag returns which were weighted so as to compensate for the fa c t that the tags were put out while the fishery was i n progress. Fishing mortality, natural mortality, and the amount of annual recruitment cannot be calculated from the present data. However, minimum estimates can be obtained which suggest that the f i s h i n g i n t e n s i t i e s are pro-bably too heavy to maintain the f i s h e r y at i t s present l e v e l of production. 7. F i f t y - e i g h t of the tags put out i n the Boat harbour region were recovered from that region i n January and February, - 8 5 -1947. This represents a percentage recovery of-6.3$ as com-pared to 18 .8$ for the same period i n the previous year. . No tags were recovered from the Baynes sound region i n t h i s same period. This was no doubt l a r g e l y accounted f o r by the closure to trawling of a l l areas with the exception of cape Lazo and Comox bay. 8 . From the 1947 Boat harbour tag recoveries the average annual length increment of lemon sole was found to be 23 .9 mm. representing an average annual increase i n length of 7.3$ or i n weight of 21.9$. 9. No f i s h tagged i n the Baynes.sound region were recovered outside that area. The.conclusion was that the lemon sole from t h i s area probably dispersed over that part of the gulf of Georgia north of Nanoose bay, a part of the gulf which i s not heavily f i s h e d by trawlers. F i s h tagged i n the Boat harbour region dispersed southward. On the eastern side of the gulf tags were recovered as f a r south as Bellingham bay, point Roberts, and the mouth of the Fras.er. r i v e r , and on the western side as f a r south as Active pass and Swanson channel. 10. The lack of returns of f i s h tagged on one spawning ground from the other grounds indicates that the populations of f i s h spawning on these grounds do not mix to any appreciable extent. 11. The composition of the populations spawning i n Baynes sound and Boat harbour were very s i m i l a r , with the exception V -86-that there were present" i n Baynes sound a larger number of immature f i s h and of mature f i s h of l e s s than 3 0 0 mm. i n length. The population at P o r l i e r pass d i f f e r e d from the others i n consisting l a r g e l y of immature f i s h . 12. An attempt was made to determine the changes occur-r i n g i n the populations of lemon sole on each spawning ground. The returns per period were expressed as i f a constant number of f i s h were tagged each time and a constant weight of f i s h caught each period. Variations i n the returns per period for the Baynes sound region expressed i n t h i s manner lead to the following conclusions: 1. The population present on the ground consisted of a small resident population and a much larger migratory population. 2. A general emigration of lemon sole began about the end of February, however, some of the f i s h present on the ground at the s t a r t of the season had started to leave by the middle of February. 3 . There was apparently a migration to and accumulation of f i s h i n Deep and Fanny bays p r i o r to emigration. In the Boat harbour region variations, i n returns per period indicate that the lemon sole did not emigrate en masse at one time but were continuously leaving the grounds during February and March. The conclusions based on t h i s method of tag analysis should be treated with a c e r t a i n amount of caution, as they are l a r g e l y based on t h e o r e t i c a l conditions and require more extensive data to substantiate them. 13. The analyses of the stomach contents of lemon sole on the spawning grounds showed that: 1. The main food of the lemon sole on the spawning grounds consists of worms, clams, and b r i t t l e s t a r s . 2. The lemon sole do not feed very a c t i v e l y during the winter. Approximately 75$ of the stomachs examined were empty. 3. Fu l l y matured f i s h feed less a c t i v e l y than immature or spent i n d i v i d u a l s . ACKNOWLEDGEMENTS I wish to express my thanks to Dr. R. E. Foerster, Director of the P a c i f i c B i o l o g i c a l Station, f o r placing at my disposal during January, 1946, the chartered otter trawler, " P h y l l i s C a r l y l e " , and f o r permitting me to use. the CCG-MV "A. P. Knight" and " S i l i q u a " when the chartered vessel was not av a i l a b l e . I am also indebted to Dr. Foerster f o r making available the necessary data f o r t h i s report. I should l i k e to extend my sincere thanks to Dr. J . L. Hart of the P a c i f i c B i o l o g i c a l Station f o r h i s many valuable suggestions and c r i t i c i s m s which have greatly aided i n the preparation of t h i s report. I should also l i k e to extend my thanks to Dr. W. A. Clemens and Dr. W. S. Hoar of .the Department of Zoology f o r their h e l p f u l suggestions and c r i t i c a l reading of the manuscript. I am indebted to Captain J . Wingate and the crew of the "P h y l l i s C a r l y l e " f or t h e i r help during the course of the inve s t i g a t i o n . My sincere thanks are due" to my wife for her help i n the preparation and typing of t h i s report. LITERATURE CITED Baranov, F. I, Hart, J . L. Hart,, J . L. Hart, J . L. Jackson, C. H. N, RIcker, W. E. Ricker,' W. E. Russell, E. S. "On the question of the b i o l o g i c a l basis of f i s h e r i e s . " U. S.. S. R., B u l l . Dept. F i s h and S c i e n t i f i c -I n d u s t r i a l Invest., 1, (1), 81-128, 1918. Catch s t a t i s t i c s of the B r i t i s h Columbia p i l c h a r d . B u l l . B i o l . Bd.Can., No. XXXVIII, 1-12, 1933. Tagging experiments on B r i t i s h Columbia pilchards. J . F i s h . Res. Bd. Can., 6, (2), 164-182, 1943. Memorandum on, the otter trawl f i s h e r y . F i s h . Res. Bd. Can., 1944. The analysis of an animal population. J . Animal Ecol., 8, 238-246, 1939. Further notes on f i s h i n g mortality and e f f o r t . Copeia, 1944, ( l ) , 23-44, 1944. Abundance, exp l o i t a t i o n and mortality of the fishes i n two lakes. Invest. Ind. Lakes and Streams, 2, (17), 345-448, 1945. Some t h e o r e t i c a l considerations on the "overfishing" problem. J . Consell., 6, p. 22, 1931. Thompson, W. F. Theory of the ef f e c t of f i s h i n g on.the stock of hal i b u t . Rept. Int. F i s h . Comm., 12, 1-22, 1937. Thompson, W. F. and W. C. Herrington. L i f e History of the P a c i f i c Halibut: ( l ) Marking experiment. Rept. Int. F i s h . Comm., 2, 1-137, 1930. Thompson, W. F. and F. H. B e l l . B i o l o g i c a l S t a t i s t i c s of the P a c i f i c Halibut Fishery: (2) E f f e c t of changes i n i n t e n s i t y on t o t a l y i e l d and y i e l d per unit of gear. Rept. Int. F i s h . Comm., 8, 1-49, 1934. Simpson, G. G. and A. Roe. Quantitative Zoology. McGraw-Hill Book Co. Inc., New York, 1939. APPENDIX. BAYNES SOUND TABLE PERl"c7FT~ "JANUARY 1 - 1 5 , 1946 BOAT DATE Welcome Pass Jan. 6 Jan. 7 Jan. 8 Jan. 9 Jan.10 Emma K. Jan. 3 Jan. 4 Jan. 5 Jan. 5 Jan. 5 Jan. o Jan. 6 Jan. 7 Jan. 7 Jan. 8 Jan. 8 Jan. 9 Jan. 9 P h y l l i s Carlyle Jan. 4 Jan. 5 Jan.12 Total AREA HOURS CATCH CATCH CORRECTED FISHED BY PERIOD FACTOR Fanny bay Fanny bay Yellow riocks Union bay cape Lazo Union bay Ship pen. Comox bay cape Lazo Union bay Fanny bay Union bay Union bay Comox bay cape Lazo Union bay Fanny bay Union bay Tagging Tagging Tagging 1,400 900 2,100 1,500 700 700 700 150 400 350 650 350 900 300 400 200 700 200 485 210 280 CATCH CORRECTED BY BOAT FACTOR 9.00 10:00 11:66 10 6 6 3 2 4 2 4 2 6 2 4 2 4 2 2 2 4 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 45 40 00 ?8:3Q 13,575 1,427 918 2,140 1,530 714 714 714 153 408 357 663 357 918 306 408 204 714 204 495 214 286 13.844 1,470 946 2,205 1,575 735 693 693 148 396 347 644 3^7 891 297 396 198 693 198 660 286 381 1^.1?? Period f a c t o r : 1.02 Boat f a c t o r : Welcome Pass 1.05 Emma K. 0.99 P h y l l i s Carlyle I.36 TABLE II BAYNES SOUND PERIOD II JANUARY 16 - 31. 1946 BOAT DATE AREA HOURS CATCH CATCH CORRECTED CATCH CORRECTED FISHED BY PERIOD FACTOR BY BOAT FACTOR Welcome Pass Jan.18 Yellow rocks 8:00 1,200 1,400 1,209 1,260 Jan.19 Fanny bay 10:00 1,410 1,470 Jan.21 Henry bay 10:00 750 755 788 Jan.22 Yellow rocks 8:00 900 906 946 Endvour Jan.25 Union bay 4:30 1,000 • 1,006 880 Jan.26 Union' bay 3; 30 500 - 504 440 Jan.2? Union bay 3:30 500 504 440 Jan.27 Union bay to Denman 2:00 500 504 440 Jan.28 Deep bay to Denman 5:00 1,500 1,510 1,320 . Jan.29 Deep bay to Denman 3:30 750 755 660 Optu Jan.27 Comox bar 1:30 — — — Jan.27 Goose spit 3:45 225 227 230 Jan.27 Comox bar 1:45 212 213 216 Jan.28 Ship pen. 1:45 100 100 102 P h y l l i s Carlyle Jan.l6 Tagging 0:45 30 30 41 Jan.18 Tagging 2:00 350 353 476 Jan.19 Tagging 1:00 300 302 408 Jan.25 Tagging 2:15 200 201 272 Jan. 2.4 Tagging 1:45 300 302 408 Jan.28. Tagging 2:00 200 201 272 Jan.29 Tagging 2:30 165 166 224 Total 79:00 11.082 11,158 11,293 Period factor: 1.006 A v a i l a b i l i t y 142.9 Boat factor:: Endvour 0.88 P h y l l i s Carlyle I.36 Welcome Pass 1.05 ^ Optu (Pooled) 1.02 TABLE III BAYNES SOUND PERIOD III FEBRUARY 1 - 1 5 . 1946 . BOAT . PATE AREA HOURS FISHED CATCH CATCH CORRECTED BY PERIOD FACTOR CATCH CORRECTED BY BOAT FACTOR Endvour Feb, 7 Deep bay to .-Denman wharf 6:00 1,500 1,140 1,320 Feb. 8 Deep bay to 6:00 Denman wharf 750 570 660 Feb. 9 Deep bay to 6:oo 760 Denman wharf 1,000 880 Feb.10 Deep bay to 660 r Denman wharf 5:30 750 570 Feb.13 Deep bay to Denman wharf 5:00 1,500 1,140 1,320 Feb.14 Deep bay to Denman wharf 2:00 500 380 440 Feb.15 Deep bay to , 760 Denman wharf . 7;oo 1,000 880 T o t a l 37:30 7.000 5,320 6.160 Period factor: O.76 Boat fa c t o r : Endvour 0.88 A v a i l a b i l i t y 164.3 BAYNES SOUND TABLE PERIOD' IV IV FEBRUARY l6_ - 28. 1946 "HOURS CATCH CATCH CORRECTED FISHED BY PERIOD FACTOR CATCH CORRECTED BY BOAT FACTOR BOAT DATE AREA Endvour Mary R i t a P h y l l i s Carlyle Good Hope II Izumi II Feb.16 Feb. 1-7 Feb.26 Feb.27 Feb.28 Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb Feb .18 .23 .24 .17 .17 .18 .18 .19 .19 .20 .21 .26 .27 .27 .28 .18 .26 .27 Feb.28 Deep bay to Denman wharf Deep bay to Denman wharf Deep bay to Denman wharf Deep bay to Denman wharf Deep bay to Denman wharf dape Lazo Baynes sound cape Lazo Deep bay Fanny bay Fanny bay cape Lazo cape Lazo cape Lazo Fanny bay Fanny bay Deep bay Deep bay cape Lazo cape Lazo cape Lazo Deep bay Deep bay Deep bay to Union bay Deep bay to Union bay 8.00 1,000 970 880 4:00 300 291 264 7:00 1,000 970 880 6:00 1,500 M 5 5 1,320 5:00 1,000 970 880 4:00 525 509 536 1:00 100 97 102 3:00 275 267 • 281 3:30 200 194 272 5:30 600 582 816 4:00 400 388 544 4:00 . 500 485 680 4:00 300 291 408 4:00 800 776 1,088 7:00 300 291 408 1:45 50 48 68 1:45 100 97 136 1:15 100 97 136 6:00 900 873 1,225 7J30 800 776 1,088 3:00 I50 145 153 2:00 700 679 378 2:00 200 194 108 1:00 600 582 324 2:00 1,000 970 540 TABLE IV (Continued) . BAYNES SOUND PERIOD IV FEBRUARY 16 - 28. 1946 BOAT DATE AREA HOURS FISHED CATCH CATCH CORRECTED BY PERIOD FACTOR CATCH CORRECTED BY BOAT FACTOR Ray Roberts Feb.16 Deep bay and Union bay 730 308 745 Feb.17 Union bay and cape Lazo 4:00 600 582-- 612 Feb.18 cape Lazo 7:00 1,700 1,650 1,735 Feb.19 cape Lazo 4:00 800 776 816 Reubina Feb.25 - 28 7?45 912 884 1,085 Total 124:30 18.142 18.508 Period factor: 0.97 Boat f a c t o r : Endvour 0.88 P h y l l i s Carlyle I.36 Reubina 1.19 Izumi II 0.54 Mary Rita) Good Hope) II )pooled 1.02 Ray ) Roberts ) A v a i l a b i l i t y 148.7 TABLE V BAYNES SOUND PERIOD V MARCH 1 - 1 5 . 1946 BOAT DATE . . . . . AREA HOURS FISHED CATCH CATCH CORRECTED BY PERIOD FACTOR CATCH CORRECTED BY BOAT FACTOR . Endvour Mar. 1 Denman 1:00 200 206 176 Mar. 2 Deep bay to Denman wharf 3:30 200 206 176 Mar. 2 cape Lazo 3:30 1,000 1,030 880 Mar. 3 cape Lazo 4:30 400 412 352: P h y l l i s C arlyle Mar. 1 Fanny bay 2:00 100 103 136 Mar. 2 Deep bay 1:30 100 103 136 Izumi II Mar. 5 Deep bay 2:00 1,000 1,030 540 Mar. 6 Deep bay 1:00 400 412 216 Mar. 7 Deep bay 2:00 . _ — Mar. 7 Deep bay 2:00 500 515 270 Mar. 8 Deep bay 2:00 400 . 412 216 Mar. 9 Deep bay 2:00 400 412 216 Mar.10 Deep bay 2:00 _ — _ Reubina Mar. 1 - 14 34:15 3,965 4,085 4,720 Total 8,665 8.926 8,034 Period f a c t o r : 1.03 Boat f a c t o r : Endvour 0.88 P h y l l i s Carlyle 1.36 Izumi II , 0.54 Reubina 1.19 A v a i l a b i l i t y 127.0 TABLE VI BAYNES SOUND PERIOD VI MARCH 16 - 31. 1946 " BOAT DATE AREA HOURS FISHED CATCH CATCH CORRECTED BY PERIOD FACTOR CATCH CORRECTED BY BOAT FACTOR Endvour Mar.16 Deep bay to -Denman wharf 3:00 100 184 88 Mar.17 cape Lazo 3:00 100 - 184 88 Mar.18. Union bay and cape Lazo 6:00 200 368 176 Mar.19 cape Lazo 6:00 1,000 1,840 880 P h y l l i s Carlyle Mar.19 Comox bar 3:30 300 552 408 Mar.19 Comox bar 2:00 100 184 136 Mar.19 Yellow rocks 1:00 80 147 109 T o t a l 24:30 1.880 1,88-5 Period factor: 1.84 Boat f a c t o r : ~ Endvour 0.88 P h y l l i s Carlyle I.36 A v a i l a b i l i t y 76.9 TABLE VII BOAT HARBOUR PERIOD A DECEMBER 1 5 - 3 1 . 1945 BOAT DATE.,." . AREA HOURS FISHED CATCH CATCH CORRECTED BY.PERIOD FACTOR CATCH CORRECTED BY BOAT FACTOR P h y l l i s Carlyle Dec.28 Boat harbour 1:20 400 176 448 Dec.28 Boat harbour :45 200 88 224 Dec.28 De Courcy Island 1:15 400 176 448 Dec.29 Boat harbour :30 200 88 224 Dec.29 Pylades Channel !35 75 33 84 Total 4:25 1,275 i i i 1.428 Period f a c t o r : 0.44 Boat f a c t o r : P h y l l i s Carlyle 1.12 A v a i l a b i l i t y 323.1 BOAT BOAT HARBOUR TABLE VIII PERIOD I JANUARY 1 - 1 5 . 1946 DATE AREA HOURS CATCH CATCH CORRECTED FISHED BY PERIOD FACTOR CATCH CORRECTED BY BOAT FACTOR 486" Curlew M. B. C. G i r l Chasam Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan Jan P h y l l i s Carlyle Jan Jan Jan Jan Jan Jan Jan T o t a l . -4 Boat harbour . 5 Boat harbour . 6 Boat harbour . 7 Boat harbour .14 Boat harbour .15 Boat harbour . 4 Boat harbour . 5 Boat harbour . 6 Boat harbour ! . 7 Boat harbour . 8 Boat harbour . 9 Boat harbour .10 Boat harbour .14 Boat harbour .15 Boat harbour . 7 De Courcy island . 7 Boat harbour . 8 Pylades ©Jbannel . 8 Centre drag .15 Centre drag .15 De Courcy i s l a n d .15 Pylades 'channel 2 8 7 4 10 5 8 8 4 4 8 5 2 4 8 00 00 30 30 00 00 00 00 00 00 00 00 00 00 00 45 40 45 45 00 00 00 450 1,000 1,250 570 1,000 500 2,000 1,400 700 600 1,000 600 300 600 1,200 100 75 35 200 150 200 40 93;55 13,970 382.5 850 1,062.5 484.5 850 425 1,700 1,190 595 510 850 510 255 510 1,020 85 63.8 29.8 170 127.5 170 34 11.874.6 1,080 1,350 615.6 1,040 520 1,940 1,358 679 582 970 582 291 582 1,164 112 84, 39.2 224 •. 168 224 44.8 Period factor: 0.85 Boat f a c t o r : Curlew M. 1.08 B. C. G i r l 1.04 Chasam 0.97 P h y l l i s Carlyle 1.12 A v a i l a b i l i t y TABLE IX BOAT HARBOUR PERIOD II JANUARY 1 6 - 3 1 . 1946 BOAT DATE AREA HOURS FISHED CATGH CATCH CORRECTED . BY PERIOD FACTOR CATCH CORRECTED BY BOAT FACTOR Curlew M. Jan.17 Boat harbour 7 :30 815 749.8 880.2 Jan.18 Boat harbour 7 too 825 759 891 B. C. G i r l Jan.19 Boat harbour 5 !00 1,000 920 1,040 Jan.20 Boat harbour 6 soo 800 736* 832 Jan.23 Boat harbour 2 soo 300 276 312 Jan.24 Boat harbour 10. ;00 1,200 1,104 1,248 Jan.25 Boat harbour 10, soo 1,200 1,104 1,248 Jan.27 Boat harbour 8: ,00 1,000 920 1,040 Jan.28 Boat harbour 10. soo 1,200 1,104 1,248 Chas«ni Jan.18 Boat harbour 8; ,00 1,200 1,104 1,164 Jan.19 Boat harbour 8; ,00 1,200 300 1,104 276 1,164 Jan.23 Boat harbour 2! ,00 291 Jan.24 B6at harbour 8. ,00 1,200 1,104 1,164 Jan.27 Boat harbour 8. 00 1,200 1,104 1,164 Jan.28 Boat harbour 8: 00 1,200 1,104 1,164 Jan.29 Boat harbour 8; 00 1,200 1,104 1,164 - Jan.30 Boat harbour 8. ,00 1,200 1,104 1,164 Jan.31 Boat harbour 4. 00 600 552 582 P h y l l i s Carlyle Jan.20 Boat harbour 1. ,00 150 138 ' 168 Jan.20 Centre drag 1 •00 150 138 168 Jan.20 De Courcy Island 1. 00 200 184 7 224 Jan.21 Pylades dhannel 45 60 55.2 67.2 Jan.26 Boat harbour 1 00 150 138 168 Jan.26 Centre drag 1 ,00 150 138 168 Jan.26 De Courcy i s l a n d 1. 00 200 184 224 Jan.26 Pylades channel 1 '00 50 46 56 Jan.30 De Courcy i s l a n d 1, 00 200 184 224 Jan.30 Pylades channel 1, 00 75 69 84 Jan.31 Boat harbour 1 00 150 . 138 168 Jan.31 Centre drag 1. 00 60 55.2 67.2 Tota l 139:15 19,235 17.696.2 19.546.6 TABLE IX (Continued)  BOAT HARBOUR PERIOD II JANUARY 16 - 31. 1946 Period f a c t o r : 0.92 Boat f a c t o r : Curlew M. 1.08 B. C. G i r l 1.04 Chasam 0.97 P h y l l i s Carlyle 1.12 A v a i l a b i l i t y 140.4 TABLE X BOAT HARBOUR PERIOD III . FEBRUARY 1 - 1 5 . 1946 BOAT DATE AREA HOURS CATCH CATCH CORRECTED CATCH CORRECTED FISHED BY PERIOD FACTOR BY BOAT FACTOR Norpack Feb.10 - ? Boat harbour 14:00 2,500 2,400 1,850 P h y l l i s C a r l y l e Feb. ? De Couroy i s l a n d & Centre drag 4:30 300 288 336 Feb. 8 De Courcy i s l a n d & Centre drag 8:30 1,200 1,152 1,344 Feb. 9 De Courcy i s l a n d & Centre drag 4:30 400 384 • 448 Feb.14 De Courcy i s l a n d 2:30 300 288 336 Feb.15 Boat harbour 2:00 200 192 224 B. C. G i r l Feb. 3 Boat harbour 5:00 800 768 832 Feb, 4 Boat harbour 5:00 900 864 936 Feb. 5 Boat harbour 8:00 1,000 960 1,040 Feb. 6 Boat harbour 8:00 1,200 1,152 1,248 Chasam Feb. 4 Boat harbour 4:00 600 576 582 Feb. 5 Boat harbour 2:00 300 283 291 Feb. 6 Boat harbour 9:00 1,300 1,248 1,261 • Feb. 7 Boat harbour 9:00 1,200 1,152 1,164 . Feb. 8 Boat harbour 9:00 1,600 1,536 1,152 Feb. 9 Boat harbour 9:00 1,100 1,056 1,067 Feb.10 Boat harbour 9:00 1,200 1,152 1,164 Norma N. Feb. 8 Boat harbour 7:00 325 312 , 796.3 Good Hope I Feb.14 Gabriola channel 2:15 • — _ ' Ray Roberts Feb. 4 Boat harbour 1:15 100 96 245 Feb. 6 Boat harbour 2:00 400 384 980 Feb. 7 Boat harbour '4:00 200 192 490 Total 129:30 17,125 16.440 17.786.3 Period f a c t o r : 0 . 9 6 Boat f a c t o r : Norpack 0.74 P h y l l i s Carlyle 1.12 B. C. G i r l 1.04 Boat factor: Chasam (Norma N. ) pooled (Good Hope I) (Ray Roberts) 0.97 A v a i l a b i l i t y 137.3 2.45 TABLE XI BOAT HARBOUR PERIOD IV FEBRUARY 1 6 - 2 8 . 1946 BOAT DATE. AREA HOURS FISHED CATCH CATCH CORRECTED . BY PERIOD FACTOR. CATCH CORRECTED BY BOAT FACTOR (Jhasam Boat harbour 2:00 300 ,351 291 Feb.21 Boat harbour 9:00 1,200 ... . 1,404 1,164 Feb.22 Boat harbour 9:00 1,200 1,404 1,164 Feb.23 Boat harbour . 9500 1,400, •1,638 1,358 Good Hope II Feb.19 Boat harbour 2:45 75 87.8 183.8 Norma N. Feb.21 Boat. harbour 4:30 85 . 99.5 208.3 Good Hope I Feb.19 Boat harbour 2:00 50 58.5 122.5 Endvour Feb.25 Boat harbour 2:00 50 58.5 122.5 Totai 40:15 4,360 5,101.3 4.614.1 Period factor: 1.17 Boat fa c t o r : Chasam- 0.97 Norma N. ) Good Hope I ) pooled 2.45 Good'Hope II) Endvour ) A v a i l a b i l i t y 114.6 TABLE XII BOAT HARBOUR PERIOD V MARCH 1 - 15. 1946 BOAT DATE AREA HOURS CATCH FISHED CATCH CORRECTED BY PERIOD FACTOR CATCH CORRECTED BY BOAT FACTOR Pearse Island Mar. 5 De Oourcy island 2:00 50 254.0 122.5: Total 2:00 50 254.0 122.5 Period factor: . 5.08 Boat f a c t o r : Pearse Island (pooled) 2.45 A v a i l a b i l i t y 6-1.3 ) TABLE XIII BOAT HARBOUR PERIOD VI MARCH 16 - 31. 1946 BOAT DATE AREA HOURS FISHED CATCH CATCH CORRECTED CATCH CORRECTED BY PERIOD FACTOR BY BOAT FACTOR Aloo Mar.22 Gabriola 6:00 400 2,132 224 Mar.23 Gabriola 3::00 • 50 . 266.5 . 28 Mar.. 28 Boat harbour 10:00 . 400 2,132 224 Mar ,.29 Boat harbour 3:00 80 426.4 44.8 Chasam Mar.24 outside P o r l i e r & G-abriola passes i 9:00 — « Mar. 26 Yellow point 8:00 — — — — — Total 39:00 120 520.8 Period factor: 5.33 Boat f a c t o r : Alco O.56 A v a i l a b i l i t y 13.4 TABLE XIV COMPARISON OF "ENDVOUR1S" CATCHES IN PERIOD II AND PERIOD III PERIO] 3 II PERIOD III DAILY CATCH x l . x l - % DAILY CATCH x2 x 2-x 2 < x2- x 2 ) 2 222.22 142.86 142.86 250.00 300.00 214.29 +•10.18 -69.18 -69.18 ••37.96 +•87.96 •• 2.25 103.6324 4,785.8724 . 4,785.8724 1,440.9616 • 7,736.9616 5.0625 250.00 125.00 166.67 136.36 300.00 250.00 142.86 •• 54.16 - 70.84 . - 29.17 - 59.48 4-104.16-+• 54.16 - 52.98 2,933.3056 5,018.3056 850.8889 3,537.8704 10,849.3056 2,933.3056 2.806.8804 S:(x1) 1,272.23 S(x1- -Sc^)2 18,858.35 S(x 2) 1,370.89 S(x2- - x 2 ) 2 28,929.88 5 =1,272.23 = 6 212.04 x 2 = 1.370.89 = 195.84 s 2 = — i : j s ( X l - x , . ) 2 4- S(x ?-5c 9) 2i = 1 "(18,858.35 + 28.929.88) = 47,788.23 (N^-lM^-lM 1 1 d 2 5 5 +- 6( J n = 4,344.38 N = 5 t- 6 = 11 s = 65.9 t - 212.04 - 195.84ir 6V9 |f b x 5T6"4.2 1 6 . 2 0 l H F Z 1/15 16.20 V3.2307 65.9 16.20 x 1.79 28.9980 -.44 65.9 65.9 P = between .6 and .7 TABLE XV COMPARISON OF "ENDVOUR1S" CATCHES IN PERIOD III AND PERIOD IV PERIOD III PERIOD IV DAILY CATCH X l ' x i " * i • ( X l - X l )2 DAILY CATCH x 2 - x 2 ( x 2 - x 2 ) 2 250.00 125.00 166.67 136.36 300.00 25O.OO 142.86 •• .54.16 - 70.84 - 29.17 - 59.48 •0L04.16 *• 5^.16 - 52.98 2,933.3056 5,018.3056 850.8889 3,537.8704 10,849.3056 2,933.3056 2,806.8804 200.00 300.00 142.86 75.00 125.00 v 31.43 ••131.43 - 25.71 - 93.57 - 43.57 987.8449 17,273.8449 661.0041 8 , 7 5 5 . 3 W 1,898.3449 1,370.89 ^x-j-x )2 28,929.88 S(x 2) 842.86 sUz-x2f 29,576.36 195.84 x\, s 842.86 ' 5 = 168.57 N r f N 2 s 4 +• 6 a 10 s = 76.4 t 195.84 - 168.57 / 7 x 5 27.27 m „ 27.2? /2.9166 _ 27.27 x 7 1 _ 46.63 = .6063 P = between .5 and .6 _ 58.506.24 - 10 = 5,850.62 TABLE XVI  CHI-SQ.UARED CALCULATIONS DEEP' BAY - FANNY BAY-Area Spawning Condition ' I II I I I IV V VI Total DB 37 1 3 7 1 .5 .-•4 1 0 . 1 4 0 FB 2 9 8 57 1 9 1 4 "2 1 2 9 66 2 1 1 2 8 2 4 1 8 12 2 6 9 Expected Values: •m'' - • - " - ,.' * DB 3 4 ; 5 2 1 0 ; 9 2 6 6 ; 56 12; 4 8 9; 5 6 '6;24-F3 3 1 . 6 8 1 0 . 0 8 6 1 . 4 4 1 1 . 5 2 8 . 6 4 5 . 7 6 Table of X . . . . . ,. -DB t 2 . 7 • 2 ; i • 4 . 4 - 7 . 5 - 5 ; 4 • 3; 8 FB - 2 . 7 - 2 . 1 - 4 . 4 • 7 . 5 • 5 . 4 • 3 . 8 Table of - • • -. " - - - „ - -,. - ,. . DB 7.29 4 . 4 1 1 9 . 3 6 5 6 . 2 5 2 9 . 1 6 1 4 ; 4 4 FB 7.29 4 . 4 1 1 9 . 3 6 . 5 6 . 2 5 2 9 . 1 6 1 4 . 4 4 Table of x£ ' " m* ' DB FB 0 . 2 1 2 4 0 . 4 0 3 8 0 . 2 9 0 9 0 . 2 5 0 1 0 . 4 5 7 5 0 . 5 1 5 1 4 . 4 0 7 2 4 ; 8 8 2 8 0 . 4 4 2 5 0 . 8 4 1 5 , 0 . 6 0 6 0 9 . 2 9 0 0 degrees of chi-squared' = " 2 2 . 4 9 1 2 P i s less than . 0 1 Continuity Correction 3 . 1 1 5 4 5 . 5 7 5 0  6 . 4 9 0 4 freedom 2 . 5 1 4 1 1 0 . 7 4 3 8 2 . 5 0 6 9 1 1 . 7 4 7 4  4 . 8 2 1 0 2 2 . 4 9 1 2 VI Total Area Spawning Condition ' ' I"' " I I III • IV y_ Table of x l corrected (x-.5) " ' ~~~r~-DB * 2 ; 2 • ! ; 6 FB - 2 . 2 - 1 . 6 • 3 . 9 - 5 . 9 - 7 . 0 • 7 . 0 - 4 . 9 • 4 . 9 Table o f ( x 1 ) 2 " - • - -DB 4;84 2 . 5 6 1 5 . 2 1 4 9 ; 0 0 2 4 . 0 1 FB 4.84 2 . 5 6 1 5 . 2 1 4 9 . 0 0 2 4 . 0 1 / 1 x 2 (x ) .. Table'of • m ' " '" " " : "" DB 0 . 1 4 1 0 0 . 2 5 4 4 0 . 2 2 8 5 5 . 9 2 6 5 2 . 5 6 5 2 FB 0 ; i 5 2 8 0 . 2 5 5 9 0 . 2 4 7 6 4 . 2 5 5 5 2 . 7 7 8 9 0 . 2 9 5 8 0 . 4 8 8 3 0 . 4 7 6 1 8 . 1 7 9 8 5 . 5 4 4 1 • 3 . 3 - 3 . 5 1 0 ; 8 9 1 0 , 8 9 i ; 7 4 5 2 1 . 8 9 0 6  5 . 6 5 5 8 •'8.8406 9 . 5 7 7 5  1 8 . 4 1 7 9 chi-squared = 1 8 i 4 1 7 9 P i s less than . 0 1 degrees of freedom a 5 TABLE XVII CHI-SQUARED CALCULATIONS " DEEP" BAY - CAPE LAZO Area Spawning Condition I II III IV V VI Total DB CL 37 "-13 • 2 4 39 17 71 16 87 •','5 17 22 "4 21 25 .10 2 12 . 140 62 202 DB CL Expected Values: 27;03 11.78 11.97 5.22 60; 29 26.71 1^:25 6.75 17; 53 7.68 8;52 3.68 LB CL Table of x " •10:0 4-1.2 -10.0 -1.2 •10.7 -10.7 -10.3 •10.3 -i3;3 • 13.3 •1.7 -1.7 DB CL Table of x 2 •. 100:00 1.44 100.00 1.44 114:49 114.49 106;09 106.09 176.89 176.89 • V 2:89 2.89 Table of x2/m DB 3.6996 0.1222 CL 8;5542 0.2759 - 12.0538 0.3981 chi-squared v=" 75; 6834 P i s less than .01 Continuity Correction 1.8989 4.2864  6.1853 6.9567 15:7170  22.6737 10.2072 0.3474 23:2320 23.0326 0.7853 52:4514 35.2598 1.1327 75.6834 degrees of freedom = 5 Area T I " Table o f ' x 1 corrected (xr;5) DB *9.5 >0i7 •10,2 CL -9.5 -0.7 -10.2 Spawning Condition HI'. IV V •VI- Total Table of ( x 1 ) 2 ' * ' 1 •DB 90; 25 0:49 CL 90.25 0.49 Table 6f" ( x 1 ) 2 / 1 1 1 ' DB 3.3389 CL 7.5397  10.8786 0.0416 0.0939  0.1355,, 104;04 104.04 l;7259 5.8952  5.6209 -9;8 • 9.8 96; 04 96.04 6.2977 14.2281 20.5258 -12; 8 •12.8 163:84 165.84 9:4541 21.5553  30.7874 •-1:2 •1.2 i;44 1.44 0;i731 0.5915  0.5654 2i:0311 47.4815  68.5126 chi-squared V 68;5126 P i s less than .01 degrees of freedom = 5 Area TABLE XVIII CHI-SQUARED CALCULATIONS FANNY BAY - GAPE LAZO Spawning Condition I II III IV V VI Tot a l FB CL 29 8 2 4 21 12 5l 16. 21 19 i 14 21 IS 2 2 I 129 : 62 191 FB CL Expected Values? 20.93 8.10 10.08 3.90 m 49.28 23.73 24.30 11.70 23.63 11.38 2.70 1.30 •EB CL Table of x +•8.1 -.1 -8.1 >.i +7.7 -7.7 -5.3 +•5.3 -9.6 +•9.6 -.7 *.7 . FB CL Table of x 2 65.61 0.01 65.61 0.01 Table of x2/m 59.29 59.29 28.09 28.09 92.16 92.16 0.49 0.49 FB CL 3.1347 0.0012 6.5089 0.0026 9.6436 01.0038 1.2031 2.4985 3.7016 1.1559 2.4008 3.9001 , 8.0984 11.9985 0.1815 O.376? 0.5584 9.5765 19.8861 29.4626 chi-squared « 29.4626 P i s less than .01 degrees of freedom - 5 Continuity Correction Area I _ II III IV V VI Total Table of xx corrected FB +-7.6 +•7.2 ' -4.8 -9.1 -.2 CL -7.6 -7.2, *4.8 1-9.1 ' r . 2 Table of ( x 1 ) 2 FB 57.76 51.84 23.04 82.81 .04 CL 57.76 51.84 23.04 82.31 .04 Table of ( x 1 ) 2 ^ FB 2.7597 1.0519 0.9481 3.5044 0.0148 8.2789 CL 5.7302 2.1846 1.9692 7.2768 0.0308 17.1916 8.4899 3.2365 2.9173 10.7812 0.0456 25.4705 chi-squared - 25.4705 degrees of freedom = 4 P i s less than .01 CHI-SQUARED CALCULATIONS TABLE XIX BOAT HARBOUR - CENTRE DRAG - DE COURCY ISLAND Area II III BH 0 0 25 CD 2 0 61 B l 0 0 -2i 2 0 U 7 Expected Values: m BH ' .51 0 30.02 CD .77 0 45.33 DI .71 0 41.65 Table of X BH - .51 0 - 5.02 CD +•1.23 0 •15.67 DI - .71 0 -IO.65 Table of x 2 BH .2601 0 25.2004 CD 1.5129 0 245.5489 DI .5041 0 113.4225 Table of x2/m BH .5100 0 .8395 CD 1.9635 0 5.4169 DI .7100 0 2.7232 2.1835 0 8.9796 Female: c h l - squared - 19.4069 df — 10 P i s between .05 and .01 Female IV Spawning Condition VI Total I Male V To t a l 2 100 102 2 68 70 0 60 60 228 2^ 2 1.76 100.24 1.21 68.79 1.03 58.97 .24 - .24 -+•.79 - .79 -1.03 •1.03 43 42 14*0 35.91 54.24 49.84 *• 7.09 -12.24 •• 5.16 50.2681 14918176 26.6256 1.3998 2.7621 .5242 4.6961 28 36 44 108 27.71 41.84 38.45 ¥ .29 -5.84 ••5.55 .0841 34.1056 30.8025 .0030 .8151 .8011 1.6192 2 98 7 148 __6 126 i l l 282 3.85 5.81 5.3^ -1.85 •1.19 1- .66 2.3225 1.4161 .4356 .6032 .2437 .0816  .9285 Male: chi-squared df P .0576 .6241 1.0609 .0327 .0516 1.0300  1-llfr? 1.3039 2 • 50 .0576 .6241 1.0609 .0006 .0091 .179g .1896 TABLE XX CHI-SQUARED CALCULATIONS PYLADES CHANNEL - PORLIER PASS Area Female Spawning Condition Male I r i I I I IV V VI Total I V T o t a l PC pp 18 3 81 _2_ 21 i o 48 22 21 6 0 Z 0 0 0 7 82 126 208 16 J2 12 20 0 20 36 -1 21 PC PP Expected Values: 39.03 3.94 59.97 6.06 M 30.36 46.64 2.37 3.63 0 0 6.31 9.69 17.54 1.46 18.46 1.54 PC PP Table of x -21.03 -.94 +•21.03 4-.94 4-17.64 -17.64 4.3.63 -3.63 0 0 4-.69 -.69 -1.54 4-1.54 4-1.54 -1.54 PC pp Table of x 2 422.2609 .8836 422.2609 .8836 Table of x2/m 311.1696 311.1696 13.1769 13.1769 0 0 .4761 .4761 2.3716 2.3716 2.3716 2.3716 PC pp 10.8189 .2243 7.0412 .1458 10.2493 6.6717 5.5599 3.6300 0 0 .0755 .0491 .1352 1.6244 .1285 1.5400 17.8601 .3701 16.9210 9.1899- 0 .1246 1.7596 1.6635 Female: chi-squared = 44.4657 df = 5 P is-.less than .01 Male c h i -df P l s • • squared = between 3.4281 1 .10 and .05 TABLE XXI CHI-SQUARED CALCULATIONS CENTRE DRAG - PYLADES CHANNEL Area. . . . Spawning Condition I ~ CD 2 PC 22 21 II I I I IV - V VI Total 0 •1 1 61 117 42 8 52. 36 -2 21 7 17 24 148 110 258 Expected Values: m CD 14.35 1772 6"7.l6 28.70 22.39 13-78 PC 10.65 1.28 49.84 21.3 16.61 10.22 Table of x CD -12.6 -1.7 -6.2 +-13.3 +-13.6 -6.8 PC +.12.6 +.1.7 +-6.2 -13.3 -13.6 +-6.8 Table of x 2 CD 158.76 2.89 38.44 176.89 184.96 46.24 PC 158.76 2.89 38.44 176.89 184.96 46.24 Table of x2/m CD H.O634 1.6802- 0.5724 6.1634 8.2608 3.3556 PC 14.9070 2.2578 0.7713 8.3047 11.1355 4.5245 ' 25.9704 3.9380 1.3437 14.4681 19.3963 7.8801 72.9966 chi-squared = 72.9966 degrees of freedom =5 P i s less than .01 • TABLE XXII CHI-SQUARED CALCULATIONS BOAT HARBOUR - DE COURCY ISLAND Area I II . Spawning Condition III IV V VI T o t a l BH 0 0 DI 0 0 0 0 25 I 43 'S 28 - 44 21 2 6 8 196 Expected Values: BH 0 0 DI <) 0 m 23.46 32.54 41.06 56.94 30.17 41.83 3.35 4.65 Table of x BH 0 0 DI 0 0 +1.5 -1.5 f l . 9 -1.9 -2.2 +2.2 -1.4 4-1.4 Table of x 2 BH 0 0 DI 0 , 0 2.25 2.25 3.61 3.61 4.84 4.84 1.96 1.96 r • Table of x2/m BH 0 0 DI 0 0 0 0 0.0959 0.0691 0.1650 0.0879. 0.0634 0.1513 0.1604 0.1157 0.2761 0.5851 0.4215 1.0066 0.9293 0.6697 1.5990 chi-squared - 1.5990 P i s between .95 and .90 degrees of freedom » 5 TABLE XXIII CHI-SQ.UARED CALCULATIONS " GEHTEE DRAG' - DE COURCY ISLAND •^ea- Spawning Condition I II I I I iv V VI Total CD 2 0 61 42 36 t 148 DI 6 0 31 55 44 "6 136 2 0 92 97 80 13 284 Expected Values : ' m" •• • • - . CD 1.04 0 47;93 50; 54 4i; 68 e; 77 DI .958 0 44.07 46.46 38.32 6.23 Table of X . •••„ . -• . * * .• . • « CD •1.0 0 •*13;I -8.5 -s:7 •;2 DI -1.0 0 -13.1 +8.5 •5.7 -.2 Table of X 2 CD 1.00 0 171.61 72.25 32.49 0.04 DI 1.00 0 171.61 72.25 32.49 0.04 Table of x2/m . - ' . ' . ... . " " _ • • - ..... CD 0.9615 0 3.5804 1.4296 0;7795 0.0059 6.7569 DI 1.0417 0 3.8940 1.5551 0.8479 0.0064 ' 7.3451 2.0032 0 7.4744 2.9847 1.6274 0.0123 14.1020 ch'i- squared 8 i " 14.1020' •'• degrees of freedom a 5 P is between .OS and .01 _ — _ Continuity Correction Area Spawning Condition I _ IT """ III IV . V VI Total Table of x x corrected CD *0.5 0 +12;6 DI -0.5 . 0 -12.6 -8;o •8.0 -5.2 *5.2 Table of' ( x 1 ) 2 ' CD o;25. 0 DI 0,25 . 0 158;76 158.76 64; 00 64.00 27; 04 27.04 :::: Table"of (x1)2/^ CD 0.2404 0 DI 0.2604 0 3.3123 3.6075 1.2663 i;3775 0.6487 0.7056 5U677 5.9510 0.5008 0 6.9198 2.6438 1.3543 11.4387 chi-squared s 11.4387- -' - - .degrees of freedom m 5 P is slightly less than .05 TABLE XXIV Area ,. Spawning Condition I II III iv V VI Total BH 0 0 25 43 28 2 '.98 CD 2 0 61 42 36 7 148 2 0 86 85 64 9 246 Expected Values: ' m" " i BH 0.8- 0 34123 33; 83 25;'47 3;58 CD 1.20 0 51.77 51.17 38.53 5.42 BH CD Table of x ' -;8 0 • .8 0 Table of x 2 BH CD 0.64 0 0.64 0 Table of x2/m BH. 0.8000 0 CD 0:5553 0 1.3355 0 -9; 2 •9.2 84.64 84.64 2.'4 1.5549  4.0076 chi-squared B 11.0919 P a .05 Continuity Correction •9; 2 -9.2 84.64 84.64 *2;'5 -2.5 e; 25 6.25 - i ; 6 *1.6 2.56 2.56 2.5019 0.2154 0.7151 6.7551 1.6541 0.1622 0.4725 ' 4.5568 4.1560 0.4076 1.1874 11.0919 degrees of freedom - 5 Area Spawning Condition i - 11 " -.- I l l IV _V Table of x 1 corrected r ~ • v " ' ;.'. VI Total BH -0.5 CD +0.5 0 0 Table o f . ' ( x 1 ) 2 ' BH 0;09 0 CD 0.09 0 Table' of i ^ ) 2 / r c L BH 0:il25 0 CD 0.0750 0 0.1875 0 •-8i 7 •8.7 75:69 75.69 2.2112 i;4620  5.6752 +8:7 -8.7 75:69 75.69 2:2574 1.4792 3.7166 •+2;2 -2.2 4184 4.84 0;i900 0;i256  0.5156 - i ; i •1.1 1:21 1.21 0.3579 0;2252 0.5611 5.0890 5.5650  8.4540 chi-squared - * 8.4540 P i s between .20 and .10 degrees of freedom = 5 TABLE XXV CHI-SQUARED CALCULATIONS BOAT HARBOUR - PORLIER PASS Area Female Spawning Condition I II III IV V VI BH PP 0 81 81 1 i 17 " 38 0 18 18 0 18 1 _2 10 Total Male I . V T o t a l .9 120 129 _1 0 — 2 1 112 12 120 BH PP BH PP BH PP BH PP Expected Values; 30.22 50.77 Table of x -30.22 •.30.22 Table of x' 913.2484 913.2484 2.99 5.01 -1.99 4-1.99 "3.9601 3.9601 Table of xz/m 30.2200 1.3244 f7>???8 .7904 48.2198 2.1148 Female: chi-squared = 147.5715 df _ 5 . P i s less than .01 m 17.16 28.84 -.16 M..16 .0256 .0256 .0015 .0009 .0024 14.18 23.82 4-23.82 -23.82 567.3924 567.3924 40.0135 23.8200  63.8335 6.72 11.28 4-11.28 -11.28 127.2384 127.2384 3.73 6.27 -2.73 ±•2.73 7.4529 7.4529 18.9342 1.9981 11.2800 1.1887  30.2142 3.1868 75 126 201 11.73 117.27 .27 2.73 -2.73 ±•2.73 4-2.73 -2.73 7.4529 7.4529 7.4529 7.4529 .6354 .0636 27.6033 2.7300  28.2387 2.7936 Male; chi-squared S 31.0323 df = 1 ' P i s less than .01 TABLE XXVI CHI-SQUARED CALCULATIONS BOAT HARBOUR - PYLADES CHANNEL BH PC Area ~r I II " I I I Spawning Condition Female -IV V VI To- I Male V To-t a l t a l BH PC 0 1 n i 2i a 25 81 46 8 14 28 -1 21 2 IZ i i 102 110 212 3 16 2d 133 24 131 136 40 BH PG Expected Values: 11.07 1.92 11.93 2.08 m 38.97 42.03 25.98 28.02 14.92 16.08 9.14 -. 9.86 14.68 4.32 121.32 35.63 BH PC Table of x -11.07 -.92 t-11.07 +-.92 -13.97 +•13.97 +20.02 -20.02 1-13.08 -13.08 -7.14 +•7.14 -11.68 4,11.68 ••11.68 -11.68 BH PC Table of x 2 122.5 449 .8464 122.$449 .8464 195.1609 195.16&9 400.8004 400.8004 171.0864 171.0864 50.9796 50.9796 136.4224 136.4224 136.4224 136.4224 Table of x2/m 11.0700 T"4"408 10.2719 .4069 21.3419 .8477 Female: chi-squared s 94.4250 df - 5 P i s l e s s than .01 5.0079 15.4273 4.6434 14.3041  9.6513 29.7314 11.4669 5.5776 10.6397 5.1703  22.1066 10.7479 Male: chi-squared =. 245.8203 df = 1 P i s less than .01 9.2931 31.5792 40.8723 1.1245 .8235  75480 TABLE XXVII  LAYOUT OF PILOT HOUSE LOG BOOK PAGE DATE PURSE SEINE WHERE FISHING DEPTH IN F. TIME OF DRAGGING TOTAL CATCH LBS. POUNDS OF PRINCIPAL FISH CAUGHT NOTES SIZE OF SPECIESt ETC. AREA HR. MIN. • ---

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