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UBC Theses and Dissertations

A biological survey of Lost Lagoon Carl, George Clifford 1932

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U ' . B . C . L I B R A R Y | CAT wo. ate-A*-A B I O L O G I C A L S U R V E Y OF L O S T L A G O O N . A Thesis submitted f o r the Degree of MASTER OF ARTS i n the Department o f Zoology. THE UNIVERSITY OF BRITISH COLUMBIA. A p r i l , 1932. George C l i f f o r d C a r l . 1-C O N T B N T S I n t r o d u c t i o n Page 3 H i s t o r y of Lost Lagoon Page5 H i s t o r y and A c t i v i t i e s of F l y F i s h i n g A s s o c i a t i o n Page 7 Statement of Problem Page 10 D e s c r i p t i o n o f Lagoon Page n (a) S i z e and Shape (b) S h o r e l i n e (c) Depth (d) Water Supply (e) Overflow System Apparatus and Methods Page 15 (a) C o l l e c t i n g (b) Sampling P h y s i c a l and Chemical C o n d i t i o n of Water Page 17 Types of Bottom and P l a n t s Page 21 (a) Clay and Pebbles with W a t e r l i l i e s (b) S o f t mud and Boulders w i t h C a t - t a i l s (c) Black Loam w i t h Cress and Grass (d) Ooze on Mud w i t h Alga Q u a l i t a t i v e Examination of Fauna Page 25 (a) L i s t of Organism Found (b) Numbers, D i s t r i b u t i o n and A s s o c i a t i o n s Food Cycle Page 36 2-F a c t o r s I n f l u e n c i n g S u i t a b i l i t y f o r Front Page 38 (a) Water Conditions Temperature Range Oxygen Supply PH S a l i n i t y (b) B i o l o g i c a l Conditions P l a n t s , P r o t e c t i v e and Food R e l a t i o n s Animals, A s s o c i a t i o n s and Competi-t i o n s Conclusions Page 4 5 Recommendations Page 4 7 B i b l i o g r a p h y page 4 9 I l l u s t r a t i o n s Page 53 - 3 I N T R O D U C T I O N During the past few years Lost Lagoon has been becoming more and more of i n t e r e s t e s p e c i a l l y to c e r t a i n anglers of the c i t y . In due time a f l y f i s h i n g a s s o c i a t i o n was formed by those most i n t e r e s t -ed i n the Lagoon f o r the purpose of making i t i n t o a fresh-water pond to provide f i s h i n g f o r t r o u t w i t h i n the l i m i t s of Stanley Park. Since the time t h a t t h i s idea was f i r s t considered various members o f the s t a f f of the P a c i f i c B i o l o g i c a l S t a t i o n at Nanaimo, B. C. have i n v e s t i g a t e d c o n d i t i o n s e x i s t i n g i n the Lagoon at i n t e r v a l s during the years 1929 and 1930. But as the problem was thought to be worthy of a more i n t e n s i v e study the present \vork w&s suggested by Dr. G. McLean F r a s e r t o be c a r r i e d on during the w i n t e r session of 1931-32. Since a work of t h i s k i n d n e c e s s i t a t e d o b t a i n i n g i n f o r m a t i o n and i d e n t i f i c a t i o n s from a number of outside sources the w r i t e r i s indebted to the f o l l o w i n g s Dr. C. McLean F r a s e r , P r o f e s s o r of Zoology i n the U n i v e r s i t y of B r i t i s h Columbia, f o r suggesting and s u p e r v i s i n g the i n v e s t i g a t i o n . Dr. W. A. Clemens, D i r e c t o r of P a c i f i c B i o l o g i c a l S t a t i o n , Nanaimo> B. C. f o r h e l p f u l suggestions and l i t e r a t u r e , Mr. C. McMbttley of the S t a t i o n , f o r suggestions and l i t e r a t u r e , Mr. G. H. Wailes, a l s o of the S t a t i o n , f o r i d e n t i f i c a t i o n of plankton, P r o f e s s o r G. J . Spencer, A s s i s t a n t P r o f e s s o r of Zoology f o r photographic v/ork and i d e n t i f i c a t i o n o f i n s e c t s . P r o f e s s o r John Davidson, A s s o c i a t e - 4 -P r o f e s s o r of Botany, f o r i d e n t i f i c a t i o n o f p l a n t s , Mr. P. A. 0. Sankey Se c r e t a r y of Stanley Park F l y F i s h i n g A s s o c i a t i o n f o r l i t e r a t u r e and a s s i s t a n c e , Mr. A. S. Wooton, Park Board Engineer, f o r maps and i n -f o r m a t i o n . -5-HISTORY OF LOST LAGOOH. Lost Lagoon i s that body of water l y i n g near the entrance to Stanley park, Vancouver, B. C. It i s separated from Goal Harbour on the east by the causeway which forms the main entrance to the park. Before the year 1916 the Lagoon formed the most western t i p of the Harbour and therefore consisted of s a l t water with t y p i c a l marine f l o r a and fauna. As the water flowed i n and out with the t i d e the greater part of the lagoon bottom was exposed during low water. Due to the fa c t that the Lagoon was "lost** to boating at lov* t i d e i t was so named by Pauline Johnson. (See Map 1) r. . . * S T A N L E Y P A T ? K Map On the completion of the sea-wall i n the summer of 1916 the Lagoon was definitely cut off from the rest of the salt water. This wall consists of rocks held i n place by wooden pil i n g with the spaces f i l l e d in with mud pumped in from the harbour bottom. The reason for building this embankment and causeway was to take the place of the bridge which formed the main entrance to the Park up to that time. In 1920 plans were completed which included the laying out of boulevards along the causeway* construction of walks around the Lagoon, and formation of one or two islands near the centre of the Lagoon for bird sanctuaries. The boulevards along the entrance were finished in 1925 but the other projects have not yet been carried out except for some construction work undertaken by re-l i e f gangs during the winter of 1931-32. During a l l this time, namely from 1916 until 1930 the water of the Lagoon remained stagnant except for occasional replenishments from the salt water of the Harbour. This addition of more salt water to water that was already concentrated by evaporation during the summer months tended to raise the s a l i v i t y a great deal. On the other hand the influx of fresh water during the rainy season and the consequent overflowing through the outlet pipe into the harbour tend-ed to lower the s a l i n i t y . This seasonal fluctuation in salt content could not have been favourable for any organisms to establish them-selves in the Lagoon. Nor could these extreme conditions be con-sidered the best preparation for the establishment of a fresh water pond although this project was not thought of at the time. -7-HISTORY AMD ACTIVITIES OF  FLY FISHING ASSOCIATION However, in the spring of 1929 a number of anglers of the City-became interested in the Lagoon as a possible fresh water pond which would provide f l y fishing for trout. Accordingly, an organization called the Stanley Park Fly Fishing Association was formed for the purpose of raising sufficient funds to cover the necessary expenses. The money was to be used for converting the Lagoon into a fresh water Lake, operating a f i s h hatchery at Beaver Lake and providing retain-ing ponds at the Lake for holding trout for replenishing the Lagoon. Operations were commenced at once. The Bominion Government supplied 130,000 Kami oops Trout eggs which were hatched at Beaver Lake. Although the water of the Lagoon was s t i l l quite salty (3.4 grams of Chloride per l i t r e ) 100,000 of these Kamloops fry were liberated during July and August. A l l of these young fi s h must have died as none were seen after the f i r s t few days. A short time before t h i s , namely in Kay, one hundred f u l l grown Cutthroat Trout and two hundred yearlings were removed from Beaver Lake and were also liberated in the Lagoon. It i s quite possible that most of these f i s h managed to exist at least for a time as Cutthroat Trout are able to adapt themselves to brackish water f a i r l y easily. It was not u n t i l the spring of 1930 that an automatic outlet was constructed and fresh water from the City supply was f i r s t intro--8-duced. As the water was now slowly becoming less brackish further attempts were made to introduce fresh water fauna and f l o r a . In March waterlilies and other aquatic plants were transplanted from Beaver Lake. As these appeared to be thriving f a i r l y well, about five thousand shrimp ( ^ W^--.f- J ) from Eed Lake and Merrit Greek, in the interior of B. C.» were introduced along with water-weed (Myrio-phyllum) from their natural habitat. In the following year, namely 1931, another lot of five thousand shrimp were placed in the Lagoon. As none of these crustaceans were seen again i t is presumed that they fai l e d to survive in their new and perhaps unfavourable surroundings. About the same time two hundred six to eight-inch Cutthroats were also introduced from Beaver Lake. These apparently fared much better as f i s h were seen rising at various times during the year and a few were removed by angling at the end of the summer. These were in good con-dition and showed considerable growth. It was at f i r s t estimated by the association that a l l work would have been completed and trout would have been of sufficient size to permit angling by the spring of 1931. However, the opening was postponed chiefly on account of the fact that an insufficient number of trout were present, and at the time, no others were available for stocking the Lagoon. The opening of the Lagoon to fishing was again postponed in 1932 owing to construction work carried on by the Parks Board and Water Works Department which necessitated lowering the level of the water throughout the winter. At the present time, March, 1932, i t i s -9-planned not to introduce more f i s h or aquatic plants u n t i l a l l dis-turbing work shall have ceased and conditions in the Lagoon shall have returned to normal. -10-STATEMENT OF PROBLEM Although the main purpose of the investigation was to make a biological survey of the Lagoon, a secondary intention was to determine i t s s u i t a b i l i t y for maintenance of trout of sufficient size to provide game for f l y fishing. In order to determine this suita-b i l i t y i t was necessary to make a study of the physical and chemical conditions of the water and of the relationships existing between the organisms found there together with the possible food-eycle for the Lagoon. -11-DESCR3PTI0N OF THE LAGOON Size And Shape As mentioned before, the Lagoon was originally the western t i p of Coal Harbour before the present viaduct was bui l t . It therefore consists of a somewhat shallow basin, the average level of which l i e s between a 9.5 and a 10.5 foot tide. The fact that i t i s below sea-level during tides higher than 10.5 feet i s rather important as w i l l be shown later. The body of water i s quite small having an area of about 50 acres and a volume of about forty million gallons according to the Parks Board engineers. It i s roughly oval in outline with only one prominent indention formed by the mouth of the inlet stream which enters the Lagoon on i t s western shore. (See Map 2) Shoreline Th© length of the shore-line not including the banks of the inlet stream i s about 1400 yards as shown by the Parks Board Map. The stream banks which are really an important part of the shoreline would add on another 300 yards. Of this total of 1700 yards about 35 j£ i s composed of clay and sand, 50JL of stones and boulders with reeds and cat-tails and the remaining 15^ of loamy banks mainly along the stream, supporting water-cress and creeping bent grass. -12-5t.t;„, © *.c.c./st. Map 2. Depth The average depth of the Lagoon i s approximately four feet and the maximum i s about ten feet. As shown by the contour lines on the map of the Lagoon (Map 2) the deepest portion l i e s near the south-east bank. The map also shows that the shallowest parts l i e along the northern shore and part of the western shore. The inlet stream i t s e l f i s about three feet deep and i s lined by f a i r l y precipitous banks, parts of which are reinforced by stone-work. -13-Water Supply The main water supply for the Lagoon comes from a pipeline which taps the nearby city water system. The water i s conveyed by a two-inch pipe which empties into the upper end of the inlet stream. This pipe i s capable of delivering about 500,000 gallons of water per day but unfortunately the supply was cut off during the greater part of the investigation to enable certain construction work to be carried on. The construction work mentioned above consisted of dredging and widening the inlet stream, building a concrete bridge over i t , reinforcing the banks with stone-work and later on excavating along the east shore next the viaduct for a new water-main. During the wet seasons of the year the Lagoon has additional sources of water in the form of small streams which drain the higher ground lying chiefly along the northern shore. The largest of these tributaries empties into the inlet stream a short distance from the mouth of the l a t t e r . (See Plates IV and V) This particular stream-le t i s of interest in that i t carries into the water of the Lagoon a f a i r l y constant though small supply of protozoa and diatoms. Other small drainage ditches empty into the Lagoon at various points along the shore. However, no polluted water enters the Lagoon. Overflow System The overflow system which was installed in the spring of 1930 •14-consists of a ten-inch overflow pipe which empties into a thirty-six inch out-let pipe communicating with the Harbour on the other side of the f i l l - i n . An automatic valve i s present which prevents the entrance of salt water when the level of the Harbour i s above that of the Lagoon, i . e . , at high tide. The system i s also provided with an arrangement which allows the level of the Lagoon to be lowered two feet when necessary for construction work. Because of the nature of the material forming the f i l l - i n and of the smallness of the over-flow pipe the system i s not 100% efficient as i t allows small amounts of salt water to seep past i t at high tide and does not permit fast enough outflow of water during heavy rains. •15-A P P A R A T U S A N D M E T H O D S  Collecting As the experimental work consisted primarily of the collection and examination of the l i v i n g organisms both macroscopic and micros-copic, no special apparatus was necessary. An ordinary dip-net was employed for collecting material along the shore amongst the weeds and the same net which was of fine mesh was used in obtaining samples of bottom ooze with i t s characteristic fauna. Plankton samples were collected by means of a plankton net of number 20 s i l k bolting cloth with a circular mouth eight inches in diameter. The shape was that of a simple cone two feet in length and ending in a 125 c.c. bottle. The net was either towed behind a boat or held in the current of the inlet stream. In a l l cases the organisms collected were taken to the labora-tory and placed in aquarium jars in which they were studied and identified. In the case of some microscopic forms such as protozoa and a few species of algae, cultures were reared in the laboratory from samples of water and bottom ooze. Representatives of the more important types of macrofauna were preserved in alcohol or formalin for future reference. By the examination of stomach contents and the study of feeding habits of the different forms, the various food-ehains and the food-cycle for the whole Lagoon was determined. -16-Sampling In order to interpret the data collected regarding numbers and distribution i t was necessary to determine the physical and chemical properties of the water in which the organisms were found. Four stations chosen by Garter on a previous occasion (Report Nov.,1930, Mottley and Carter, 19 ) were again used so that results could be compared. Of these stations No. 1 was located near the outlet pipe close to the causeway, No. 2 approximately in the middle, No. 3 at the mouth of the supply stream and No. 4 in a slight bay on the south shore as far removed as possible from the disturbing factors of the water entering at Station 3 or possible salt water seeping through the causeway near Station 1 (See Map 2) In most cases as the water was very shallow samples, tempera-ture and pH readings were taken from the surface layer, fhe water samples were collected in pint bottles and the water was analyzed for chloride content by the usual Mohr Method of titu4tion using Y large samples (50 c.c.) when the amount of Chloride was small. 1'he temperature for both a i r and water was taken by means of an ordinary thermometer and the hydrogen ion concentration (pH) was determined at the same time by the colorimetric method using the La Motte Stan-ce dard, Brom-thymal Blue or Cresol Red. Readings were taken at roughly weekly intervals when time permitted. -17-PHYSICAL AND CHEMICAL CONDITIONS IK THE WATER To show the condition of the water i n the Lagoon from the time when observations were taken f i r s t , u n t i l the present investi-gation Table 1 has been constructed. The data has been taken from the reports of former investigations carried on by various members of the Biological Board (16,17,18 & 19). These are unpublished re-ports made available by the kind permission of Dr. W. A. Clemenst Director of the Biological Station. D a t e Deptk Tie Vnper dfure Chlort rt<f y °c o p C.C^S per Citre / J J ^ 13/29 23-5 75-0 4-64 C5-4 ' 765 4-33 vWface 215 711 : z-o 8-4 Bottom — — — — <Surf ace 71 45-2 6-lS 1 + 7 7-0 ? 4 f 0 — — — flOv-3/30 S^urface 90 4<W •3 5 0 7-0 4&-0 7-59 •411 7 4 1 Table 1. •18-The table shows a series of temperatures and water analyses taken at various times and in various parts of the Lagoon, i t is particularly interesting in that i t covers the time when the Lagoon was changing from salt to comparatively fresh water. Observations taken on July 13, 1929, indicate that the temper-ature of the water i s capable of reaching a rather high maximum. The amount of dissolved oxygen, although lower than that found at other times, was s t i l l large enough to be favourable for f i s h - l i f e . A l -though fresh water other than rain and drainage had not been intro-duced as yet the s a l i n i t y was f a i r l y low. The average value was about one third of that found for the water in Coal Harbour but s t i l l over eight hundred times that of nearby Beaver Lake. The records for August of the same year show a considerable improvement in general conditions. Although the temperature was found to be s t i l l quite high, the salinity was found to be reduced to a value almost half of that reported in the previous month. The one and only pH reading upon which i t is perhaps not sufficient to base conclusions, showed a definite rise in a l k a l i n i t y . The data collected in November of the same year show a s t i l l greater change in conditions. Along with the much lower temperature a corresponding larger amount of available oxygen was found as might be expected. The value for the salin i t y was found to be s t i l l lower possibly owing to the influx of rain and drainage water during the wet season. The pH showed a sudden decrease which might be explained by assuming the presence of organic acids produced by the rapid decay -19-of algae. From the last set of readings unt i l the next set i s an inter-val of almost a year during which time no observations were taken. However, according to the report of November 3, 1930, the conditions were found to be very similar to those noted during the f i r s t obser-vation (July 13/29). The fact that the sa l i n i t y does not appear to have been decreased as much as might be expected although fresh water had been entering the Lagoon continuously for several months, may be explained in two ways; either salt water had been entering through the outlet pipe or through the sea-wall or else salt was being slowly leached from the bottom mud which had been deposited while the Lagoon was s t i l l connected with the Harbour. Subsequent investigation show-ed that the source of the salt water must have been through or around the outlet pipe as small tr i c k l e s were found entering the Lagoon near that spot during high tides. To show the condition of the water during the course of the investigation, Table 2 has been prepared. Although i t i s far from being complete i t is sufficient to i l l u s t r a t e the conditions existing in the Lagoon for the greater part of the winter. The temperatures show a gradual decrease until November 22 when ice covered most of the surface of the water. During the cold-est part of the season the temperature remained f a i r l y constant ex-cept at Station 1 at which point warmer salt water was making i t s entrance from Coal Harbour. After the disappearance of the last covering of ice, about February 10, the records indicate a slow rise i n temperature. In general the temperature of the water approaches -19(a)-Date Station Te.inperatu.re °c op Gxa-ms p*r Ittre p H Oct 14/31 1 13-0 55-1 •47 7-2 Oct-18 '•' r 12-a 55-0 •4-7 7-4 3 12-0 S 4 0 • Oct-25 1 77 4-80 •55 73 3 101 50-5 _—„ — . Oct-31 1 9-8 50-0 •6"l 7-3 3 104- 5/0 • — i — — 1 77 480 •46 7-2 1 -z 318 72 1 0-0 32-0 1 5-3 . 42-0 / S-30 8-4 3 0-0 32-0 -02 7-2 *' Feb-y • 1 , 4-4 40-5 /S-19 8* -3 -I 3i a •06 70 4-' 0-0 C32-0 •03 70 1 •5> 340 •31 74 2-o 36-0 . -0^ Ftbz? • 3 7-/ 45-0 02 70 &.C.C •/« Table 2. 20-nearer and nearer to that of the a i r as the water circulates from the inlet to the outlet. values Most of the sali"»ityAin the table, given as weight of Chloride per l i t r e , are from samples taken at Station 1 near the outlet. The values are comparatively uniform except on certain occasions when salt water was found to be entering the Lagoon in large quantities. At these times samples were also taken at Station 3 near the inlet as a check on those taken at the outlet. These samples showed that although there was only a small trace of salt present in the freshest parts the s a l i a i t y was s t i l l five times that found for Beaver Lake by Carter (19). On the whole the waters of the Lagoon s t i l l contain an appreciable amount of salt ranging from five to over one hundred times the amount usually found in bodies of fresh water such as Beaver Lake. The readings for hydrogen ion concentration of the water show nothing unusual except on the same occasions when salt water was entering the Lagoon. At these times the water immediately around the outlet showed a pH value of 8.2 to 8.4 which might be expected to be the case in conjunction with the high salin i t i e s found at the same time. At other times the pH was on the alkaline side except at Station 3 where i t approached neutrality and even slight acidity on one occasion. On the whole the water of the Lagoon during the winter months, may be described as cool, slightly turbid, slightly brackish and slightly alkaline. -21-TYPES OF BOTTOM AND PLANTS There are roughly four types of bottom present in the Lagoon each supporting i t s own characteristic but scanty flo r a . Type A The f i r s t and most barren type i s composed of hard clay intermixed with pebbles and patches of gravel. It i s at present quite bare of plant-life except perhaps for a few waterlilies (Nuphar Polysepala) introduced from Beaver Lake. This unproductive type of bottom is found near the shore along the southern and east-ern banks (plate IV Fig. 2) and includes about 35$ of the shoreline. Perhaps as conditions become more favourable some form of plant l i f e such as N i t e l l a or Myriophyllum w i l l become established and convert this waste bottom into an important part of the Lagoon. Type B The next type of bottom i s composed of soft mud i n which &re imbedded scattered stones and boulders (Plate V Fig. 6). More introduced waterlilies,small clumps of Myriophyllum Verticillatum and Water Shield (Brasenia Schreber) are found here in the deeper parts while in the shallows and in the marshy section lying above the water level are found dense growths of cat-tails (Tvpha L a t i - f o l i a ) and a reed (Scirpus Sobustus). The c a t - t a i l is rapidly ex-tending i t s limits out into the water by the production of "runners* at right angles to the shoreline. As the outermost border is extended thus, the network of roots so formed i s gradually 22-f i l l e d in with sediment and decaying material so that the shoreline i s slowly creeping out into the water. fhe reed which i s found mixed in with the cat - t a i l i s of particular interest as i t i s usually associated with brackish water. It no doubt became established when the Lagoon s t i l l contained salt water and has continued to exist under the changed conditions. It w i l l be interesting to note i f i t continues to thrive by becoming adapted to i t s new environment. This type of bottom with emerging reeds and cat-tails extends the f u l l length of the northern shore and along most of the western shore on either side of the mouth of the inlet stream. It makes up approximately 50$ of the total shoreline. Type C The third and most interesting type of bottom is composed of black loamy s o i l which provides an anchorage for semi-aquatic plants such as Water-cress (Radicula Nasturtium-aquaticum), Creeping Bent Grass (Agrostis) and submerged Myriophy1lum. The Cress i s rooted at the water's edge but grows out from the bank forming excellent cover for insect larvae and small crustacea. The Creeping Bent grass i s found in the same places but i s more t e r r e s t r i a l in i t s origin. Along the bank i t grows in its typical form but the large masses which have crept into the water show a characteristic growth of elongated rootlets and long curved leaves which emerge from the surface of the water. It also provides excellent shelter amongst i t s matted roots and stems. The Myriophyllum i s typically aquatic, -23-being found some distance from shore. It has been introduced from Beaver Lake where i t is very p r o l i f i c . This loamy type of bank and bottom i s found only in the inlet stream, the bed of which has been excavated from this type of s o i l (See Plate IV, Fig. 4). It makes up the remaining 15$ of the shoreline. Type D The fourth type forms the major part of the Lagoon bottom as i t includes a l l the bottom except those parts already mentioned as lying along the shoreline. It i s made up of the original mud deposit over which l i e s a f a i r l y thick layer of ooze and organic detritus which, in shallow places, i s easily stirred up by wave action. This type of bottom i s also rather interesting as i t supports a thick growth of alga (genus Enteromorpha) which i s undoubtedly of marine orig i n . This alga i s composed of elongated cylindrical branching filaments which grow up to the surface of the water except in the deepest part. By the middle of August when the weather is warmest the growth is so thick, according to the boat-house manager, that boats have great d i f f i c u l t y in making progress through i t . Towards the end of the summer i t begins to die down and by November i t has a l l disappeared except for decaying masses which float near the sur-face or are cast up on shore. Although i t i s a hindrance to boating in sunsner this alga i s beneficial to the Lagoon as a whole as i t pro-vides shelter in one season and food through decay for bacteria, pro-tozoa, rotifers, etc., in the next. It also adds materially to the -24-organic detritus which i s a very necessary base of supplies for main-tenance of aquatic l i f e . It w i l l also be interesting to note i f this marine form continues to exist in the fresh water of the Lagoon or f a i l s to survive the change. -25-Q U A L I T A T I V E E X A M I N A T I O N O F F A U N A . LIST OF ORGANISMS FOUND IN LAGOON. ALGA. Aphanocapsa elachista Hapolosiphon intrieatus Scenedesmus quadricauda Bnteromorpha Spirogyra Botryococcus Mougeotia Hormidium Golankinia ghlorosphaera DIATOMACSA. Fragilaria capucina Campylodiscus Navieula Odoiitidium Biatoma PROTOZOA. Sarcodina Difflugia constricta • globulosa 26-Difflugia oblonga * p r i s t i s " bacilliarum var. elegans * olliformis * pyriformis Nebela americana var, retorta " c o l i a r i s 11 tincta * dentistoma * tubulosa " griseola Pseudo d i f f l u g i a g r a c i l i s Centropyxis aculaata Trinema 1inears " enchelys Englypha c i l i a t a * strijosa * brachiata Quadruella symmetrica Arcella sp. Acanthocystis spinifera * myriopoda Pompholyxophrys punicea Archer * ovuligera -27-MASTIG-QPHORA • Oikoiaonas termo Bodo globosus Astasia sp. CJLIATA. Paramo eciuia Spirostomum Urocentrum Halteria Oxytricha glaucoma Trichoda Colpoda Colpidium putrinum Vorticella R6TIFERA. Rattulis cylindricus (?) Asplanchna priodonta (?) Brachionus sp. ANNULATA. Tubificidae sp. Ilumbricus sp. BRYOZOA. Plumatella polymorpha var. oppressa CRUSTACEA.  INSECTA. -28-gollembolla. One species Ephemerida. One species (larva) Qdonata. Zygoptera - Chromogrion sp. Anisoptera - at least one species Trichoptera. One species (larva) Family Phryganeidae Hemiptera. Callicorixa praeustus Kepidae species Diptera. Culicidae - Anopheles species Tipulidae.one larva Chironomidae - several unidentified species Cladocera* Baphnia pulex var. obtrusa Copepoda, Cyclops fuscus Canthocamptus sp. Isopoda. Exosphaeroroa oregonensis (Dana) Asellus tomalensis Hydracarina. Arrhenurus globator (?) -29-PISCES. Gasterosteus cataphractus Cottus asper Richardson Salmo c l a r k i i NUMBERS, DISTRIBUTION AND ASSOCIATIONS. A L G A E . Most of the algae being of microscopic size, was collected in the plankton net or was found in cultures of water taken from various parts of the Lagoon. Disregarding the branching filamentous type of marine origin the amount of algae present was very small except on a few occasions. The amount of diatoms was also very small especially in the more open parts of the Lagoon away from the water supply. Diatoms were found in greatest abundance in the very small stream flowing into the main inlet stream about twenty yards above i t s mouth (See plates f i g . 5). The dominant species here during the winter months was Fragil-a r i a capucinia. which occured in long, f l a t filaments but which was found only in small numbers. The scarcity of these important forms of algae and diatoms has a decided effect on the fauna of the Lagoon as they form the basis of a l l food. P R O T O Z O A . Fair l y large numbers of protozoa were found, possibly on account of masses of decaying algae (Enteromorpha) floating near the shore. Most of the c i l i a t e s and flagellates were identified, into genera only, from cultures prepared from these decaying masses. The other protozoa, principally Rhizopoda and Heliozoa, were found i n the small tributary stream along with the filamentous diatoms. The -31-^protozoa are important only in that they are used as food by other small animals* R O T I F E R A. The Rotifers were represented mainly by two species, Rattulis cylindricas and As plan chna priodonta (?) which occured in large num-bers during the f a l l months. These Rotifers made up the greatest part of the plankton during this time and appeared to be universally distributed. Possibly their great abundance at this time was due to the presence of large numbers of protozoa which were feeding on the decaying algae found everywhere in the Lagoon. B R Y 0 2 0 A. Although no Bryozoans were found in the Lagoon at the time, colonies of Plumatella polymorpha appeared in cultures on standing i n the warm laboratory. These must have arisen from stat©blasts collected by accident along with the water sample. The fact that these fresh-water forms of Bryozoa form winter buds or statoblasts which are easily transported from place to place explains how Pluma-t e l l a probably became distributed from Beaver Lake where i t i s quite common. As Bryozoans do not generally form an ar t i c l e of diet for other animals they are mentioned here as being interesting only on account of their possible origin. -32-I N S E C T A. The insects found to be most abundant in the Lagoon were water boatmen (Callicorixa praeasius) and lay f l y larvae both of which are important as fish-food. The boatmen were found along the shore wherever vegetation i n the form of rushes, grass or water-cress existed. The May f l y larvae were found only in the weeds along the inlet stream. As both these forms feed only on plant tissue or de-t r i t u s they form a direct link in the food-chain between plants and fishes. Several unidentified species of midge larvae (Chironomidae) were found by examining the ooze on the bottom of the inlet stream. Although Chironomids are an important a r t i c l e of diet for fishes they were not present in large enough numbers to be of much use as food. A few dragon-fly, damsel-fly, and mosquito larvae were also found i n the masses of weed in the stream but these also were present in small numbers. In the laboratory some boatmen were observed feeding upon,live chironomial larvae but this i s probably an exceptional case. C R U S T A C E A . Large numbers of Cladocer&u-s- (Daphjlla, polex) were found by sweeping with a net under bunches of overhanging grass and water-s-cress along the banks of the inlet stream. With them were found num-erous copepods a l l of one species (Cyclops fuscusj which were apparently feeding upon the same plant material as the cladocerans. Both crustaceans were being eaten by sticklebacks (Gasterasteusj which were collected at the same time. In the f i r s t collections most of the cladocerans were found to contain summer eggs or developing young but towards the end of the season numbers were found bearing ephippia containing winter eggs. Soon after this the numbers of Saphnia decreased rapidly, possibly on account of the oncoming of cold weather and large numbers of winter egg-cases were found floating among the weeds on the surface of the water. The copepods appeared to remain more constant in numbers a l -though the older ones bearing egg-masses disappeared before the end of the season. Copepod nauplii were found at a l l times in the plankton of both the open Lagoon and the stream. The copepods and cladocerans no doubt originated from Beaver Lake by being carried over on water plants, in samples of water or by birds which frequent both bodies of water. I S 0 P 0 0 A. Of the two isopods found in the Lagoon one in particular, viz; Exosphaeroma oregenensis, was of especial interest as i t is of salt-water origin (Plate VI). It i s a common form found everywhere in Puget Sound, on the beach at low tide, under rocks and on wooden p i l -ing. (2) This isopod appeared to be doing quite well in spite of the great change in i t s habitat. It was found in f a i r l y large numbers -34-i n a l l parts of the Lagoon even where the water was freshest. It occured under stones, bits of wood along the bare shore and amongst grasses and water-weeds along the inlet end of the Lagoon. Although no individuals were found carrying eggs at that time of the year many small speeimens were taken showing that breeding must have taken place. It i s to be hoped that this i s true and that they continue to thrive as these isopods were found to form a large part of the diet for trout. The other isopod was a typical fresh-water form of the genus Asellus. It agrees with the description of A. tomalensis, as given by Fee (2) i n every respect but in that of the proportions of the head. This crustacean was possibly introduced along with the water plants from Beaver Lake where Asellus occurs in f a i r l y large numbers. Only a few of these isopods were found, a l l in the freshest part of the Lagoon near the inlet stream. The Prickly Bullhead (Oattus asper) i s another fish present in the Lagoon in f a i r l y large numbers. As i t i s often found in brackish water near the mouths of rivers and streams i t probably was present in the Lagoon before i t was cut off from the Harbour. This sculpin i s universal in distribution being found in a l l parts of the Lagoon particularly amongst the aquatie plants of the inlet stream. It preyB upon the sticklebacks which are most numerous there but also feeds on earthworms, grubs and aquatic insect larvae. As there is considerable range in size in the specimens collected, the smallest being about 5 centimetres long and the largest about 12 centimetres, -35-i t i s presumed that these bullheads are breeding in the Lagoon and may increase in numbers. Although they are probably not directly harmful to mature trout they do no good since they help i n depleting the available food supply. Although two species of trout (Salmo c l a r k i i and S. riyularis ? Kamloops) were introduced into the Lagoon i t is probable that only the former i s now present since the Kamloops trout were introduced as small fry when conditions were very unfavourable. During the i n -vestigation no trout were seen at any time exeept one dead specimen found early in October. This particular fish appeared to be in good condition and had plenty of food i n i t s stomach. No cause of death was apparent. Another type of marine f i s h seen in the Lagoon during the f i r s t part of the Survey was a species of flounder. As no specimens were obtained the f i s h was not identified. It i s unlikely that these f l a t - f i s h w i l l become adapted to the fresh water since several dead ones were seen early in the season. -36-F O O D C Y C L E . Since the Lagoon has so recently been changed to fresh water the interrelations of the plants and animals present there do not form such a complex maze as i s found in an older lake. An attempt has been made therefore, to note the relationships of the more impor tant forms and to determine food-chains which go to make up the food cycle for the Lagoon. Diagram 1. -37-This i s shown in Diagram 1 which includes only those organisms which are most important or most numerous. The arrows represent the processes by which the food materials may be transformed, that i s , the paths by which nutritive materials may circulate. Wherever doubt i s present as to the relationship between different "links'* i t i s designated by means of dotted lines. The diagram can only represent, then, possible paths for food materials and can not give any idea of relative importance of the different processes or relative numbers of the different organisms. Some of the separate food-chains such as Detritus - Isopods -Trout can be said to be present in any part of the Lagoon as each "l i n k " of the chain i s more or less universally distributed. However the whole cycle as represented, can take place only in the sheltered water of the inlet stream since that i s the spot where a l l the forms representing the links are found. Thus i t can be seen that as new types become established changes w i l l occur in the various relation-ships which w i l l affect the food-cycle and may even cause the ex-tinction of some forms already existing. -38-FACTORS INFLUENCING SUITABILITY FOR TROUT. According to Rawson (12) "The physical and chemical conditions that control the l i f e and l i f e processes in a lake may be unified by tracing them back to two fundamental conditions. The f i r s t i s the shape of the lake which must include i t s depth, area and conformation of i t s shores. The second i s the geographical position of the lake including the nature of i t s drainage area and the climatic conditions f-aref of the region. These conditions are linked up with the fauna and flora of the lake to form a working unit or microcosm." Such conditions as the temperature and the chemical properties of the water are commonly spoken of as factors limiting the l i f e of the pond or lake. However, they cannot be looked upon as simple or isolated factors but rather as the culmination or result of a number of agencies. These physical and chemical factors are interrelated and interdependent in a most complex manner. In an equally complex manner the biological a c t i v i t i e s of the lake are interrelated both among themselves and with the physical and chemical a c t i v i t i e s . But for convenience in investigation and discussion these "factors" must be dealt with separately. The factors determining the su i t a b i l i t y of the Lagoon for maintenance of trout are discussed i n the following ordert WATER CONDITIONS. Temperature range Oxygen supply PH -39-Saliaity BIOLOGICAL CONDITIONS. Plants, protective and food relations Animals, associations and competitions -40-W A T E R C O N D I T I O N S . TEMPERATURE. According to Outsell (3) *a sufficiently lew temperature has been considered the prime requisite of trout waters since trout cul-ture began, and for an untold number of years before that. For the present, at least for '•normal* water containing abundant oxygen and free of toxic substances, low summer temperature must be considered the limiting factor requisite for the trout and tolerated by the associates*. Unfortunately, as the investigation was carried on only during the winter months very l i t t l e i s known about water conditions in the Lagoon during the summer. However, the l i t t l e that i s known shows that the temperature conditions are far from being ideal for trout. As shown by the table the highest temperature recorded on August 2/29 was 24.2° C (76°F.) and the lowest taken at the very head of the stream was 15.0°C (59°F.). August 2/29 Temperature In Lagoon 24.4°C. 76* F. Inlet stream below bridge 21.9* C. 72° F« Inlet stream above bridge 18,8°0. 68° F. Head of stream 15.0°C. 59 aF. TABLE 3 - Summer temperatures in Lagoon. -41-It i s true that had the a r t i f i c i a l water supply been running at that time the temperature would not have reached such a high max-imum. Nevertheless i t i s doubtful that any trout could survive such temperature extremes even assuming that plenty of oxygen was present. Although the high temperature in summer is the result of a number of agencies the greatest cause i s undoubtedly the shallowness of the water. This lack of depth prevents the formation of a therm-ocline or stratum of water separating the warm surface layer from a very much cooler deeper layer. It has been shown by Fearee (10) that i n the summer* organisms tend to migrate from the warmer layer to the cooler waters beneath. This migration of course i s impossible in the Lagoon where the bottom water i s very l i t t l e cooler than the surface. O X Y G E N Again the records are very scanty for this important factor, especially for the summer months which i s the most c r i t i c a l time. Jewell and Brown (4) found that even bog lakes "with the lowest oxygen content found (2.56 c.c. per l i t r e ) contained adequate oxygen at the time of study for the maintenance of fish l i f e * . They also noted that the low oxygen content was produced by processes of putre-faction common to bogs* It i s probable then, that the amount of free oxygen which i s large during the cooler seasons may^  in the Lagoon, be considerably reduced during the late summer by the rapid decay of large quantities of algae together with the high temperature. -42-It i s unfortunate that no data is available for this c r i t i c a l period except that given in Table 1. pH. As a result of their investigation of the fauna of bog lakes Jewell and Brown (4) were convinced "that pH as such is rarely a limiting factor to the distribution of fresh-water fi s h in natural waters". In general more f i s h are found i n alkaline or neutral water than in acid water. It can be said then, that as far as pH i s con-cerned the Lagoon, which has a pH of 7.2 - 7.4 i s not unfavourable to f i s h l i f e . 5 A L I B I T Y Since very l i t t l e i s known about the effect of dissolved salts on fresh-water fi s h l i t t l e can be said about the effect of the s l i g h t l y brackish water of the Lagoon on trout. It i s possible that the small amount of salt present does not harm the eut-throats in the Lagoon as this species of trout i s capable of entering the sea. However, the salitiity of the water does effect the trout indirectly since i t prevents the establishment of most fresh-water organisms necessary for food. -43-B I O L O S I C A L C O N D I T I O N S . It has been shown already that although the amount of l i f e in the Lagoon i s comparatively scanty the relationships between the var-ious forms are very complex. The effect of these relationships on trout should now be considered. PUNTS The ultimate source of a l l food i s found in plants which are represented in the Lagoon chiefly by algae and diatoms. Although a variety of forms are present,in actual numbers they are very scanty. This effects the well-being of trout indirectly as the amount of available food i s limited commencing with the f i r s t "link'* of the food-chain. The larger aquatic and semi-aquatic plants are important most-ly as shelter for the smaller forms of l i f e and to a lesser extent as food. Most, of those found in the Lagoon have been introduced from Beaver Lake and therefore their numbers are very few as yet. This scantiness also has an indirect effect upon t r o u t - l i f e , in that i t limits the number of small forms which usually find refuge in shelter-ing plants. ANIMALS The effect of animals or animal communities on trout i s also a matter of food. As illustrated in the diagram of the food-cycle for the Lagoon (Baa. 1) trout depend upon a number of different -44-organisms for food. Perhaps the most important groups in the food-ehain i s that formed by Daphnia and Cyclops. These crustaceans are present in f a i r l y large numbers and help to form the link between plants and many other animals which are dependent upon them. Using terms suggested by Elton ( l ) they may be called "key industry" animals and may be said to f i l l a definite "niche* in the community. It can be understood then, that with a limited supply of food for these important forms as i s the case in the Lagoon, the supply of food for trout must likewise be limited. -45-C O H C L U S I O N . Considering the fact that the Lagoon,as a fresh-water lake, i s so young i t has made good progress in productivity from conditions which might be called zero as far as fresh-water food types are con-cerned. This rapid progress has been brought about mainly by intro-duction of aquatic plants and animals from nearby Beaver Lake where they are well established. But i n spite of this progress towards a fresh-water unit conditions in the Lagoon can hardly be said to be favourable for the well-being of trout. It i s true that the amount of available food in the water i s not sufficient to supply more than a few trout but this d i f f i c u l t y could be overcome to a certain extent by a r t i f i c i a l feeding. It i s also true that the water s t i l l contains an appreciable amount of salt especially at the eastern end. This condition i n i t s e l f does not harm the f i s h but i t does have a detrimental effect on the food-types of the trout. This i s made evident by the fact that nearly a l l the aquatie organisms present i n the Lagoon are found where the water i s freshest, that i s , in the inlet stream. Ko doubt, as the water be-comes fresher these important organisms w i l l spread to other parts of the Lagoon and thus this fault w i l l be corrected. The greatest factor which presents the Lagoon from being fav-ourable to the maintenance of trout i s the unnaturally high tempera-ture of the water during the hot weather. An attempt was made in the previous section to explain the cause of this abnormal temper--46-ature and i t s effect on trout* In the following section a few suggestions are offered on controlling this condition. In general then, i t i s the opinion of the writer that Lost Lagoon i s s t i l l unfavourable for trout for the above reasons but that i t i s capable of being made a successful trout-pond i f some means are found for correcting these unfavourable conditions. -47-R E C O M M E N D A T I O N S . The following recommendations are more in the nature of su-ggestions and i t is asked that they be looked upon as such. (1) It has been shown that the factor which has the greatest effect on trout i s the excessively high temperature of the water i n the summer months. It has also been shown that the Lagoon would not be unfavourable to t r o u t - l i f e i f this high summer maximum were avoid-ed. This extreme temperature could be lowered in three ways* (a) By increasing the depth through dredging. One or two deep parts could be produced by pumping or dredging out mud from the deeper portions that are already present. The mater-i a l from this work could be used to form an island which would provide more shade and shelter for aquatic l i f e . (b) By raising and maintaining the water-level. Increasing the depth by raising the level of the water even as l i t t l e as a foot would also help to lower the mean summer temperature. (c) By increasing the flow of water from the i n l e t . This would be the simplest and least expensive way of controlling the temperature. It would certainly produce a sufficiently low temperature at least in the inlet stream i f not in the Lagoon as a whole. In order to handle the increased amount of overflow i t would l i k e l y be necessary to increase the dia-meter of the outlet pipe. (2) Hext in importance to a favourable temperature is the presence -48-of suitable water plants to serve as food and shelter to the various animals upon which the trout depend. It i s suggested then, to con-tinue introducing aquatic plants from Beaver Lake and other sources u n t i l these desirable forms have become definitely established in the Lagoon. As conditions are approaching nearer and nearer to those of a fresh-water lake this should be accomplished in the near future. (3} Steps should be taken to prevent the entrance of more salt water from the harbour sinee the presence of dissolved salts in the Lagoon tends to limit a l l fresh-water organisms to the inlet stream by rendering the rest of the Lagoon unfavourable for them. (4) If i t should happen that trout f a i l to establish themselves i n the Lagoon in sufficient numbers to allow angling, i t i s su-ggested, as an alternative, to introduce some other form of f i s h -l i f e which would thrive under present conditions. Such fish as bass, sunfish, perch or carp could be tried to determine which might be most suitable. Although these fi s h are much less desir-able than trout they would supply a form of sport at least to some people. -49-B I B L I O G R A P E Y . 1* Siton, Charles 1927 Animal Ecology Sidgwieh and Jackson, Ltd* - London. 2* Fee, A* R. 1926 Isopods of Departure Bay and Vicinity with Description of Sear Species, Variations and Color Notes. Contributions to Canadian Biology & Fisheries* (Kewr- Series Vol. I l l No. 2) 3. Gutsell, James S. 1929 Influence of Certain Water Conditionsj especially dissolved Oxygen, On trout. Ecology - Vol.X - No. 1 January /29. 4. Jewell, M. 1. and Brown, H. W. 1929 Studies of Northern Michigan Bog Lakes. Ecology - No. 4, October 1929. 5. Jordan and Evarmann 1898 - Fishes of North and Middle America, United States National Museum, Washington. 6. Kudo, Richard R. 1931 - Handbook of Protozoology Chas. C. Thomas, Baltimore, Maryland. 7. Matheson, R. and Hinman, E. H. 1930 - Season^ Plankton of Spring fed chara pool vs. -50-Temporary flbodland pool in relation to Mosquito Breeding. American Journal of Hygeine Vol. XI #1. Needhara, J . G. and Lloyd J . T. 1916 - Life of inland Waters. Comstock publishing Co. Noland - Lowell E. 1925 - Factors limiting Fresh-water Ciliates Ecology. Vol. VI. No. 4 October /25. Pearse, A. S. 1926 - Animal Ecology McGraw-Hill Publishing Co. Petersen, Walburga 1926 - Seasonal Succession of Animals in a Chara -Cattail Pond. Scology Vol V l l . No. 3 July 1926. Rawson, Donald S. 1930 - Bottom Fauna of Lake Simcoe and Role in Scology of the Lake* University of Toronto Press, $34 Ont* Fisheries, Research Laboratory. Reed, 6. & Klugh, A. B. 1924 - Correlation between Hydrogen ion Concentration and Biota of Granite and Limestone Pools. Ecology Vol. V. No. 3, July /24. Shelford, V. E. and Eddy, Samuel 1929 - Methods for Study of Stream Communities. Ecology #4, October 1929. •51-Wailes, 6, H. 1930 - Munday Lake and i t s Ecology.-Museum and Art Botes. - September 1930, Art, Historical & Scientific Association, Vancouver, B. C. UNPUBLISHED REPORTS OF PACIFIC BIOLOGICAL STATION. Clemens, W. A. 1929 - July 13 - Report on Lost Lagoon. Mottley, 0. McC. 1929 - August 31 - Lost Lagoon Report. Hart, J . L. and Pritchard, A. L. 1929 - November 29 - Examination of Lost Lagoon. Mottley, C. Mc C. and Carter* Neal M. 1930 - November 3, Report on Beaver Lake and Lost Lagoon. PLAOIE III F i g . 2 Looking east along southern shore towards the Viaduct. PLATE IV F i g . 3 Northern shore from Station I. C a t t a i l marsh i n foreground. F i g . 4 Inlet Stream looking east towards i t s mouth. Tributary entering on l e f t . PLATE V Fi g . 5 Tributary entering muddy water of the Inlet Stream. F i g . 6 Mouth of Inlet Stream. Heeds and c a t t a i l s i n the background. PLATE VI *J-g« 7 Exosphaeroma oregenensis (Dana) marine isopod found i n the fresh water Lost Lagoon. 


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