"Science, Faculty of"@en . "Zoology, Department of"@en . "DSpace"@en . "UBCV"@en . "Wickett, William Percy"@en . "2012-03-01T20:54:46Z"@en . "1951"@en . "Master of Arts - MA"@en . "University of British Columbia"@en . "Both field and laboratory experiments have shown lethal effects from the deposition of silt on incubating salmon eggs. Because silting appears to deprive the eggs of sufficient oxygen, theoretical limits of flow and oxygen content of sub-surface water were studied. Data have been gathered on temperature, oxygen content, and rate of flow of water twelve inches below the surface of the gravel at Nile creek. Field determinations of oxygen consumption of pink, chum and coho eggs have been made. In heavily-silted portions of the bed there was an insufficient supply of oxygen for pre-eyed chum salmon eggs. A field method for determining oxygen content and apparent velocity of gravel water is presented."@en . "https://circle.library.ubc.ca/rest/handle/2429/41069?expand=metadata"@en . "ON THE, OXYGEN SUPPLY TO SALMON EGGS by WILLIAM PERCY WICKETT A THESIS SUBMITTED IN PARTIAL FULFILMENT OF1 THE REQUIREMENTS FOR THE DECREE OF MASTER OF ARTS in the Department of ZOOLOGY We accept this thesis as conforming to the standard required from candidates for the degree of MASTER OP ARTS. Members of the Department of Zoology THE UNIVERSITY OF BRITISH COLUMBIA April, 1 9 5 1 ON: THE OXYGEN SUPPLY TO SALMON EGGS A preliminary study on pre-eyed chum salmon eggs in the gravel at Nile creek by William Percy Wickett ABSTRACT Both field and laboratory experiments have shown lethal effects from the deposition of s i l t on incubating salmon eggs. Because silting appears to deprive the eggs of sufficient oxygen, theoretical limits of flow and oxygen content of sub-surface water were studied. Data have been gathered on temperature, oxygen content, and rate of flow of water twelve Inches below the surface of the gravel at Nile creek. F-ielcfc determinations of oxygen consumption of pink, chum and coho eggs have been made. In heavily-silted portions of the bed there was an insufficient supply of oxygen for pre-eyed chum salmon eggs. A f i e l d method for determining oxygen content and apparent velocity of gravel water is presented. ..\u00E2\u0080\u00A2oOo.\u00E2\u0080\u00A2\u00E2\u0080\u00A2 CONTENTS Page I. INTRODUCTION 1 The Problem 1 Literature 1 II. FORMULATION OF PROBLEMS 5 Oxygen demand ' 6 Oxygen supply i n the gravel 7 Method of evaluating gravel water conditions . . . . . 9 III. DETERMINATION OF OXYGEN REQUIREMENTS OF PRE-EYED CHUM EGGS 10 Method 10 Results 11-Discussion 14-IV. DETERMINATION OF OXYGEN CONTENT AND VELOCITY OF GRAVEL WATER 14 Method 14 Results 16 Discussion 17 V/. DEVELOPMENT OF GRAVEL WATER SAMPLER 18 Description . . . 18 Calibration 20 VI. EVALUATION OF OXYGEN SUPPLY AT NILE CREEK 22 VII. SUMMARY 23 VIII. ACKNOWLEDGMENTS 24 IX. LITERATURE CITED 25 APPENDIX A - Oxygen consumption data . APPENDIX B - Gravel water data Figure 2 to follow 16 3 \u00C2\u00AB 18 4 \" \" 21 5 \u00C2\u00AB \u00C2\u00AB 22 Table I \" \" 11 II .-\u00E2\u0080\u00A2 \u00E2\u0080\u00A2 \" \" 20 ...oOo\u00E2\u0080\u00A2\u00E2\u0080\u00A2\u00E2\u0080\u00A2 - 1 -I. INTRODUCTION The Problem In a study of the freshwater development of the chum salmon (Onco-rhynchus keta) at Nile creek on Vancouver island, high losses (averaging 70$) have been found in the pre-eyed stage. It is believed that a real part of this loss is due to oxygen deficiency, associated with the pres-ence of s i l t in the salmon redds. To assess this, i t was necessary to obtain basic knowledge of the oxygen requirements of the eggs and of the oxygen available in the stream bed. A technique that may have general application in the field of fishery biology is required for the rapid assessment of oxygen availability in salmon redds. Literature Two studies of the natural incubation of salmonoid eggs are of major interest, those of D. Hobbs (1937, 194-0, 1948) in New Zealand and W.M. Cameron (1939, 1941) in British Columbia. In both places, pre-eyed losses were greater than eyed losses and were associated with the amount of very fine material in the redds during the development'of the ova be-fore eyeing. In his classic study of the natural reproduction of New Zealand salmonoids, Hobbs recognized an adequate oxygen supply as an important factor influencing egg survival. Mortalities at the various stages of development of eggs and alevins were observed by sampling redds in numerous localities. In New Zealand he concluded Mthat the extent of losses of fertilized ova in undisturbed redds depended primarily on the amount of very fine material in the redds during the development of ova before eyeing\". However, these losses were less than 1 0 $ , and other losses were dominant and limited the population size. H:e listed seven factors to be considered i f anything in the nature of an exact determination of the permeability of a redd were attempted, with a view to ascertaining whether ova receive a sufficient amount of oxygen:: 1. The number and size of ova per unit volume of bottom material. 2. Their oxygen requirements. 3. The permeability of the redd material. 4-. The contours of the redd. 5\u00C2\u00AB The rate of flow of water over the redd. 6. The amount of available oxygen per unit volume of water. 7\u00C2\u00AB Water temperature. Hbbbs, however, was not able to satisfy his own conditions. Cameron suggested that for McClinton creek pink salmon there is a definite relation between pre-eyed and total mortalities of eggs and ale-vins, and that low mortalities are almost invariably associated with medium to coarse gravel, good circulation, and the absence of s i l t or plant material. This suggests that when pre-eyed losses are high they become dominant, and that conditions conducive to a plentiful supply of oxygen reduce this mortality. Recent work indicates a direct relation between flow of streams dur-ing the period of spawning (which includes the early pre-eyed stage) and chum salmon population size four years later in the Vancouver island district (Neave and Wickett, 194$). The size of particles carried by water is related to the velocity of flow (Mavis, Ho and Tu, 1935). If - 3 -the flow decreases at spawning time, increasingly fine s i l t may accumulate on the spawning beds. S i l t i n g may reduce the rate of flow of oxygen-bearing water i n the gravel since the permeability of a porous medium varies as the square of the diameter of i t s grains (Mavis and Wilsey, 1936). Mavis and Wilsey also found that the permeability of sand varied with the f i f t h or sixth power of the porosity, i.e., degree of consolidation, (page 5). This restriction of flow by consolidation i s emphasized by Ellison (1950) who says that deep-sealing of fields may be caused by the i n f i l t r a t i o n of turbid rainwater, the ground becoming nearly impervious to water within twenty-five years under certain conditions.' This process could very well be taking place i n stream beds. A third factor that may also be associated with reduced surface dis-charge of streams i s reduced sub-surface flow through the gravel from the banks of streams, due to the lowering of the water-table, which is one of the primary causes of decreased stream flow. (Hoyt, 1942). Water transports the oxygen that i s consumed by salmon eggs. The oxygen consumption of salmonid eggs has been studied by several workers but none has related his findings to conditions i n gravel beds. The oxygen consumption of Atlantic salmon (Salmo salar) eggs has been carefully studied by Lindroth (1942) and by Hayes and his associates (Hayes, 1949). Kawajiri (1925) recorded the oxygen consumption of the eggs of Oncorhynchus masou, though the temperature of the experiments is not given. Smith and Kleiber (1950) give formulae for the relation of size and oxygen consump-tion of various f e r t i l i z e d eggs at 25\u00C2\u00B0C Zeuthen (1947) made a general study of body size and metabolic rate i n the animal kingdom. - 4 -None of the above give data suitable for present requirements nor are any studies of the oxygen demand of chum salmon eggs known to the writer. Besides the two authors mentioned previously there i s ample evidence to indicate the importance of adequate water flow over incubating eggs i n the writings of Schaeperclaus (1933), Hata (1931), Vibert (1950), Hubbs, Greeley, Tarzwell (1932), Shetter, Clark, Hazzard (194-6), Hewitt (1931), White (194-2) and Moffett (194-9) \u00E2\u0080\u00A2 From these authors i t i s clear that an improvement of the quantity and quality (oxygen content, temperature, freedom from s i l t and chemicals) of the water supply usually improves the survival of incubating salmonoid eggs. Shaw and Maga (1943) carried out tests on the deleterious effect of mining s i l t . One or two points from their paper are of particular importance: \" S i l t added during the i n i t i a l stages of incubation and continued for either a few days or a longer period, causes severe damage resulting i n low yields of fry. The emergence of f r y above the gravel i s retarded .... (and) .... i n general these fry were smaller and weaker than those of the control series and a number of deformities were noted. The larger number of whole eggs remaining i n the gravel at the conclusion of this experiment i s significant as i t shows a tendency for undeveloped eggs to resist decomposition, apparently due to a protective coating of s i l t . \" The same effect has been noted i n the \"controlled-water\" section of Nile creek, where eggs planted the previous year have been found preserved in the gravel after twelve months. The composition of the stream bottom - 5 ~ in one such area was of consolidated large stones, sand, s i l t and small gravel, and the surface flow was good with l i t t l e surface silting. In another of these areas the gravel was (and s t i l l is) heavily silted. On the other hand, excellent incubation was found where there was reduced surface flow, much surface silting but a spring upwelled close by and the gravel was loose. In view of this, s i l t of itself did not seem to be lethal, but in certain instances i t would appear that circulation of the water i s so greatly reduced that there i s insufficient oxygen for the disintegration of dead eggs in gravel. . . . o O o . . . II. FORMULATION OF PROBLEMS Three main problems present themselves: 1. oxygen requirements of chum salmon eggs; 2. the mechanism of transport of oxygen to eggs in the gravel; 3\u00C2\u00AB a method of evaluating water conditions in the gravel. In this study the following symbols are used: A = oxygen demand of the eggs, i.e., the amount of oxygen necessary for normal metabolism, in mg.02/egg/hr. R'. = radius of egg, in mm. p = porosity of gravel, i.e., total volume of pores-bulk volume u = component of true velocity in direction of flow, in mm*/hr. v = apparent velocity of water, i.e., discharge. area do = amount of oxygen dissolved in water, in mg.Oo/litre. - 6 -G z value of de at which A i s sharply reduced. n = number of eggs i n a column i n the direction of water flow. Oxygen requirements of chum salmon eggs The oxygen demand i s assumed to be the same for a l l eggs of similar past history at a given temperature and at a similar stage of develop-ment. For Salmo salar eggs the oxygen demand increases with age and tem-perature (Hayes, 194-9), but i s independent of the amount of oxygen dis-solved i n the water, provided the dissolved oxygen (do) i s above a c r i t i c a l value (G). The oxygen demand i s abruptly reduced when the amount of oxygen dissolved i n the water i s reduced below this c r i t i c a l value. For the stages immediately preceding hatching, the c r i t i c a l value i s greater than f u l l saturation because the oxygen consumption of the egg i s being limited by the rate of diffusion of oxygen through the capsule. The c r i t i c a l value of dissolved oxygen varies with the oxygen demand of the egg, the square of i t s radius and the rate of diffusion of oxygen through the egg (Krogh, 1941)\u00E2\u0080\u00A2 It may be expressed i n oxygen tension, i.e., partial pressure of oxygen i n millimeters of mercury multiplied by the percentage saturation; i n atmospheres, l*e., 760 mm. Hg pressure of oxygen; i n the degree of oxygen saturation of the water; or simply parts, per million at a given temperature. Values of the oxygen demand (A) of pre-eyed chum salmon eggs are required at temperatures that occur i n nature, and at values of dissolved oxygen (do) greater that the c r i t i c a l value (C). In view of the lack of specific knowledge, f i e l d determinations are preferable to deductions - 7 -made from the literature. A and G may be found by recording the reduction of do per unit time i n either moving or static volumes of water i n which the eggs are immersed. Oxygen supply i n the gravel The oxygen supply to eggs i n water w i l l depend on the volume of water per unit time (Q) delivering oxygen to the eggs, and the oxygen per unit volume (do) dissolved in the water; i.e., gross supply i s if accurate readings are required at points of low oxygen saturation. liable II gives the results of the test. Velocity. A trough was made of 2\" x 12\" x 6' boards. Screens were set i n i t and the volume between them f i l l e d with gravel from Nile creek TABLE II CALIBRATION OF SAMPLER FOR DISSOLVED OXYGEN Water samples were taken by sampler six inches away from standpipes i n Nile creek \"controlled-water\" section. Temp. OC. DO ppm. Diff . 1443 June 30, 1950 Surface s 8B? Sampler 12.5 11.1 11.1 10.6 0.4 2.3 1-9 4g minutes to f i l l 1140 July 4, 1950 Surface 8B5 Sampler 1400 July 4, 1950 Surface 4 Sampler 1050 July 5, 1950 Surface 2 Sampler Surface 1 Sampler 0953 July 6, 1950 Surface 5 Sampler 11.8 11.2 10.2 12.9 12.6 12.5 11.8 11.8 11.8 11.8 11.8 11.8 11.8 11.8 12.0 10.6 0.13 0.54 10.4 5.2 5-3 10.9 6.7 6.25 10.9 9.8 8.9 10.8 8.5 8.5 0.4 0.1 -0.5 -0.9 2-| minutes to f i l l 4 minutes to f i l l 2 minutes to f i l l 0 Sampler i n gravel one hour. Four volumes discarded to clear water. 1110 July 6, 1950 Surface 6 Sampler 11 ..8 10.8 12.0 10.1 12.0 10.0 -0.1 F i r s t sample used; water clear. 1125 July 11, 1950 Surface 7 Sampler 11.0 10.8 10.8 11.0 9-6 9.8 + 0.2 xStandpipe number. - 2 1 -to give a bed 1 1 3 cm. x 2 2 cm. x 2 5 . 5 cm. and head and t a i l water pools at either end of the gravel bed. Water was lead into the head water pool where the water was maintained at a constant level by an overflow set so that there was no surface flow over the gravel. The outflow was a tap set in the centre of the end wall of the t a i l water pool. Samples of water were collected from the tailwater, measured by volume and timed to determine the rate of flow at the beginning and end of each test. One of the standpipes was set 1 2 centimeters into the centre of the gravel bed and the procedure for obtaining the dilution of dye outlined above was followed for various rates of flow. The apparent velocity was calculated by dividing the discharge (cc./hr.) by the cross-section of the bed ( 5 6 1 sq. cm.). Dye dilution i s reported i n equal volumes of water added per hour (vol./hr.). The standard series of dyes was made up by taking one volume of concentrated dye. An equal volume of water was added and one volume of this diluted dye was used as the f i r s t of the series, the remainder had one volume of water added and half of the second dilution became the second of the series, etc. (Dilutions half way between those above may be useful.) For some of the tests the standpipe was set with two of the openings i n line with the direction of flow and i n others, forty-five degrees off the line of flow. The dilution rate appears higher with two openings in line with the flow. Three comparison tests with the sampler and standpipes i n the creek bed gave identical results. From figure 4 i t appears that the standpipe at 4 5 \u00C2\u00B0 from the direction of flow has a dilution rate similar' to the sampler. Velocities converted from dilutions at the higher rate 0 4 1020 mm./hr. ; 5 v o l . / h r . 0 1 2 3 4 5 DYE DILUTION, (equal volumes o f water added per hour) VOL./HR. Pig. A . CALIBRATION OF STAND PIPE AND SAMPLER FOR APPARENT VELOCITY V e l o c i t i e s were c a l c u l a t e d from d i scha rges through a t rough o f 561 square cent imeter c r o s s - s e c t i o n c o n t a i n i n g g r a v e l . V e l o c i t i e s encountered i n nature were below the i n f l e c t i o n p o i n t s . Average maximum p o r o s i t y was 23$. Fig. 5. CURVE OF LIMITING VALUES OF DISSOLVED OXYGEN AND APPARENT VELOCITY OF WATER TO SUPPLY THE FULL OXYGEN DEMAND OF PRE-EYED CHUM SALMON EGGS AT 8\u00C2\u00B0C. For values to the right and above the curve, supply exceeds demand; be-low and to the l e f t , supply i s less than demand. Some low values found in the gravel of the Nile creek \"controlled-water\" section are plotted. - 22 when used i n expression (5) w i l l give a greater calculated quantity of oxygen being supplied. The maximum porosity of the gravel bed i n the trough was 23%. The porosity of samples from Nile creek was 22%. The sampler gives promise as a means of evaluating the dissolved oxygen content and apparent velocity of gravel water. It should be calibrated in the type of gravel to be sampled. . . . 0 O 0 . . . VI. EVALUATION OF OXYGEN SUPPLY AT NILE CREEK The standpipes at Nile creek do not give a f u l l coverage of the con-trolled water section nor were the readings taken consistently enough to evaluate the entire bed's oxygen supply during the pre-eyed stage, but certain values of dissolved oxygen and apparent velocity are compared with a curve of limiting values that just maintain f u l l metabolism of the pre-eyed eggs (f i g . 5)\u00C2\u00BB nA - 117*R v(do-C)10\"' i s taken as the expression of the sufficiency of oxygen supply. A,R,C, are constants for eggs of a given age and at a given temperature, v and do are variables. I f the oxygen supply just equals the demand, then expression (5) i s the equation of the positive values of a curve of the form x(y-C) = K that is the curve of limiting values of v and do. At any point above or to the right of the curve the oxygen supply exceeds the particular oxygen demand being considered. At any point below or to the l e f t , the f u l l demand i s not being met, probably with f a t a l results. Using the values A =.0003 mg./egg/hr., R = A mm., C = 1.3 ppm.02, for n = 1, expression (5) reduces to v(do-1.3) = 5\u00C2\u00AB5, and for n = 10 to v(do-1.3) = 55\u00E2\u0080\u00A2 The asymptotes of these curves are v = 0 and do = I.3. In figure 5 there are plotted several points well to the l e f t or below the curve of limiting values. Those points with do (14-35) 13*5 .000822 917.6 2.17 52: 5 15.7 14.9 .000905 920.8 1.81 43 1 13*7 12.8 .000697 916 *S 2.58 48 4 13.8 .000746 916 .3 2.50 48 5 14.0 .000710 921.6 3.01 46 5 13.7 .000745 922.6 6.95 7.37 37 13 13.9 13.2: .000884 921*2 6.95; 5.81 43 m 14.5 13.9 .000694 922.5 1.86 203 0 55.5 51.6 .00196 calala. ted for 4-8th hours .00168 923.3 3.37 202 0 57.0 53.2 f u l l period .00182 calculated for 9th hour .000242 917.4 3-89 198 0 56.4 52.5 f u l l period .00188 calculated for 10th hour .000069 916.9 4.16 203 0 57.4 53.5 f u l l period .00177 Bottle Wt. of Species Date Time Period Temp. Thio. D.Ol water pH D.O. No. of f/t. of Vol. of Wt. of mg./egg/hr. Age \u00C2\u00B0 C cc. p.p.m. i n reduced eggs eggs eggs chorion F = .624 bottle Live Dead 1949 Pink eggs Oct. 18 1400 0 hr. 6.9 18.8 11.73 Eyed 20 0900 43 hr. 6.2 16.25 10.14 919.6 1.59 100 0 19-5 .001 .00033 28 days Pink eggs Nov. 7 2100 0 hr. 7*85 17.55 10.95 33 days 8 0900 12 hr \u00E2\u0080\u00A2 7.9 16.35 10.20 922.5 0.75 95 6 24.4 23.0 .00055 8 2130 24 hr. 8.3 15.10 9.43 917.4 1.52 96 4 19-7 .00057 9 0945 36 hr. 8.2 15.09 9.42 923.7 1.53 95 5 19.7 .00039 Pink eggs Nov.\" 7 2100 0 hr. 7.85 17-55 10.95 48 days 8 0900 12 hr. 7.9 16.10 10.05 8 2130 24 hr. 8.3 15.25 9.51 9 0945 36 hr. 15.61 9.74 Pink alevins Nov. 22 0930 0 hr. 8.2 18.50 11.55 7 days old 2230 13 hr. 8.0 5.79 3.62 23 0930 24 hr. 8.0 5.05 3.15 23 2145 36 hr. 8.0 0.05 0.031 923.3 0.90 100 4 21.1 .00067 916.9 1-44 96 _ 4 19-7 .00054 918.0 1.21 93 7 19.2 .00032 922.5 7.94 62' 4 12.0 10.9 1 .0090 2 .0084 923.3 8.40 32 8 7.81 7.0 1 .0100 . 2 .0080 917.4 11.52 34 13 9-3 8.3 1 .0094 2 .0068 no opercular movement, heart beat 6-13/min., a l l subsequently died. 1. assumed death took place at beginning 2. assume no death Bottle Species Age Date Time Period Temp. \u00C2\u00B0C. Thio. cc. F = .612 D.0. p.p.m. 1950 Coho eggs Jan. 23 1330 Eyed -1450 0 hr. 22.21 13.61 67 day 29 U 5 5 150 hr. 16.66 10.19 1516 0 . 1 15.31 9-38 1501 0 .7 16.77 10.25 1 5 H 16.36 10.-00 F = .728 Coho eggs Mar. 7 (0830 0 hr. 4-9 17.6 12.81 hatching (0955 8 0930 24 hr. 4 . 3 16.45 11.99 Coho eggs Mar. 7 0 hr. 4 . 9 17.6 12.81 nearly - 8 2253 38 hr. 4-3 16.06 11.70 hatching 9 0931 48 hr. 4*2 15 .62 11.38 2048 60 hr. 4 . 3 12.82 9.34 2135 60 hr. 4 . 3 14 .64 10.66 10 0950 72 hr. 4-1 15.78 11.49 1001 72 hr. 4 . 1 13 .62 9.93 1014 72 hr. 4 . 1 14 .36 10.45 Coho alevins Mar. 8 1050 0 hr. 4-3 17.6 12.81 just hatched 9 0826 21 .6 hr. 4 . 3 14.76 10.75 Wt. of water pH D.0. No. of Wt. of Vol* of Wt. of mg./egg/hr. in reduced eggs eggs eggs chorion bottle Live Dead 920.8 3-24 98 2 3 0 . 4 28.5 0.01 .000204 917.6 7.1 4-23 95 5 30.3 28.6 .000251 920.2 3-36 83 8 27.2 25 .4 .000220 917.4 3.61 94 3 29.4 27.6 .000220 average - . 0 0 0 2 4 1 916.7 0 .82 ' 8 egg 0 2 .9 2.65 ' x r> .00297 2 a l . 2 .00262 922.5 1.11 10 0 3 . 0 2 . 9 1 .00269 918.0 1-43 9 egg 0 3 - 0 2 .9 11.0 1 4 3 0 Nov. 8 / 4 9 Pool 3 \" 1600-1610 Nov. 9 / 4 9 0835 Pool 7.1, # 2 gauge 0.7 2 6 . Nov. 16/49 1 4 3 0 - 1 5 3 0 Air 9 . 2 , Pool 7.6 # 2 gauge 0.71, Pool gauge 2 \u00C2\u00A7 \u00C2\u00AB , 1 1 . 4 5 27. Nov. 2 2 / 4 9 1 4 3 0 - 1 5 1 0 ' Air Pool 8 . 3 # 2 gauge 1 . 5 - 2 . 4 Pool gauge 5 | \" , 1 1 - 3 8 28. Nov. 25/49 1 0 1 5 - 1 1 4 5 Pool 8 . .0 # 2 gauge 2 . 4 Pool gauge T\u00C2\u00A3-T>n 29. Dec. 3 / 4 9 1 5 3 0 Air 3 . 4 , Pool 5 - 9 , 3 | \" 3 0 . Dec. 7/49 0 9 5 0 Pool 4.7 # 2 gauge 0 . 7 Pool gauge 0.7, 12.52 1 11.2. 2 9.75 4 7.1 1 8.1 2 9.23 1 3 .23 1 7-3 1 7.6 2 10 .62 1 8 .3 2 10.11 . 8 5 1 5 . 7 1 4.7 2 11.46 11.6 11.1 11.4 6.91 6.75 6 . 8 . 1 1 5 6 . 8 8.05 8.0 -7.4 7.52 5.74 7.1 .109 7.5 7.6 7.6 7 . 5 7 . 4 7 . 6 9.6O 6 . 0 3 1 0 . 3 1 8.1 8.0 8.3 8.65 8.35 10.96 8.0 .83 1.05* 6.5 6.9 6.1 4 . 8 5 . 4 4 . 8 9 . 4 1 9 . 0 4 9 . 6 4 1 1 . 3 1 1 . 4 1 1 . 1 H . 2 9 . 2 4 8 . 4 9 . 1 5 5 - 4 1 7 . 2 7 . 4 7 . 3 6 . 7 8.05 8.0 8.0 8.1 10.29 9.0 8.89 1.29 . 1 6 . 1 3 . 2 1 . 2 2 7.2 7.4 7 .3 7.8 7 . 6 7 . 6 7 . 5 5 8.1 10.1 8.92 9 .03 0.8 8 . 0 8.1 8.2 8.2 9 . 8 3 8 . 9 5 8-16 1 . 3 7 1.67 1.0 .74 . 6 8 5.8 6.2 6.2 7.7 4 . 8 5 . 1 5 . 1 7 . 2 1 0 . 4 0 7 . 0 6 8 . 1 5 0 . 2 3 11.8 5.27 6.9 7 .3 1.97 .0006 7 . 6 7 . 6 2.08 8.0 0.27 .60 7.0 6 . 6 0.0 IA and IB, 4A and 4B, 8A and 8B, having wide standpipes, placed to take experimental eggs. NILE CREEK CONTROLLED SECTION, 1949-50. 8 A B 9 iced 1.1 2.2 iced up 7.9 6.4 2.8 2.7 2-5 Standpipe number l x A B' 2 X 3 Spring 4 X A B 5 6 7 31. Jan. 20/50 1 1.0 0.9 0.9 1\u00C2\u00AB7 2.0 1.5 1.5 1.5 1.0 1.0 1.1 Air 0 . 5 , Pool 1.0 2 12.3(^11.5) 9.1 5.8 8.7 11.75 12.3 10.5-#2 gauge 0.35 Pool gauge 2\", 12.45 32. Jan. 21/50 0935 1 Pool 0 .7 , 2\\" 33. Feb. 13/50 1510 1 3.0 #2 gauge 0.8,235\u00C2\u00B0C. 2 10.6 D .0 . 13.4 34* Feb. 18/50 0845 1 2.2 2.2 2.2 2.2 2.2 2.8 2.2 2.2 2.3 2.4 2.5 2.5 4*6 2 . 5 H 4*6 Pool 2 .5 , 4\" , 2 11.73 11-74 11.35 13.41 11-97 11.75 13.5* 4.26 #2 gauge 1.2 Kcovered by surface water 35. Feb. 21/50 0900-1030 1 2.5 2.1 2.3 . - ' 2.5 2.5 2.5 2.6 4.5 4\u00C2\u00BB5 Pool 3 \" , 2.8\u00C2\u00B0, D.0.13.35 2 12.02 10.08 7.76 10.48 12.39 12.02 11.40 4*5 0.18 #2 gauge 0 .9 . 10.30- 3 1.0 1.2 0.3 1.8 1.0 1.6 0.3 0.4 1 .6 2-2 1.6 2 O.4 0.6 1.8 1100=1530-1600 Vol./hr. Pool 2.8 1530/21 pool set at 2\" 36. Feb. 22/50 0900-1030 Pool 2\" ,3-0\u00C2\u00B0, D .0 . 13.5 #2 gauge 1.0, 1030-1515 1545 3.5 1600 pool set at 4\" which caused bed to be covered with s i l t during night. 37. Feb. 23/50 0900-1030 Pool 2 . 8 , 4\",#2 gauge \u00E2\u0080\u00A2 0 . 9 . 1030-1100 to 1530-1600, 13.10. 1530-1600 3.0 38. Apr. 18/50 1455-1550 Air 9-5, Pool 3|-\" Pool 6 .2 , 12.50 1 2.8 2.8 2-9 2.8 2.8 3.0 2.8 2.8 2.8 2.8 2.8 2-9 5-0 3:.l 4-5 4-5 1 2.9 2.9 2.9 2.8 2.9 3.1 2-9 3.0 2.9 2.9 2.9 2.9 4-5 4-5 4.8 5.9 2 11.61 12.47 14.95 9.96 9.94 9.14 9-56 12.40 11.9 12-34 11.88 11.95 5.04 5-79 4.66 0.19 3 0.8 1.2 1.2 1 .0 0.3 1.2 1.4 1.0 1.4 0.4 0.3 1.2* 0.2 1.4 0.6 1 3-5 3.3 3.5 3.5 3.0 3.1 3-5 3.3 3.5 3-6 3-6 5.6 4.0 5.0 5.0 1 2.8 2.8 2.8 2.8 2.9 2.9 2.9 2.9 2.9 2.8 2.9 2.9 4*2 3.6 4-5 4*9 2: 11.81 12.71 12.84 10.04 10.02 11.49 9.72 12.12 12.83 12.88 12.15 11.78 4-67 7.7 4-38 0.166 3 0.6 0.7 0.4 0.4 1.0 0.5 1.6 0.2 0.5 0.3 1.1 0.2 0.6 0.8 1 3.0 3.0 3-0 2.9 3.0 3.1 3.0 2.9 3.0 3-0 3.0 4\u00C2\u00AB2 3.9 4.7\" 5-0 Bed covered with s i l t . . . . . . 1 5.8 5.1 5.7 4.8 5.1 5.3 2 11.70 10.32 10,85 9*55 3-58 3.97 ...oOo. "@en . "Thesis/Dissertation"@en . "10.14288/1.0106670"@en . "eng"@en . "Zoology"@en . "Vancouver : University of British Columbia Library"@en . "University of British Columbia"@en . "For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use."@en . "Graduate"@en . "On the oxygen supply to salmon eggs"@en . "Text"@en . "http://hdl.handle.net/2429/41069"@en .