Evaluation of Hatchery versus Wild Sockeye Salmon Fry Growth and Survival in Two British Columbia Lakes

Sockeye salmon fry were collected from the Fulton River spawning channel at Babine Lake, British Columbia, in May 1978. The fish were reared for 26 d in enclosures in the spawning channel and were sampled every 7 to 10 d. The sagittae were removed from 25 fish from each sample, and the growth rings in one otolith from each fish were counted. A regression of the number of rings on the number of days since capture showed that these rings are, on average, formed daily, beginning at the time of emergence. A number of possible technical and biological causes of variation in ring counts within and between samples are considered.Key words: otolith, sagittae, daily growth rings, sockeye salmon fry

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Distribution, Growth, and Survival of Sockeye Fry (Oncorhynchus nerka) Produced in Natural and Artificial Stream Environments

Journal of the Fisheries Research Board of Canada ◽

10.1139/f69-027 ◽

1969 ◽

Vol 26 (2) ◽

pp. 229-267 ◽

Cited By ~ 5

Author(s):

J. G. McDonald

Keyword(s):

Sockeye Salmon ◽

Survival Rates ◽

Lake Basin ◽

Growth And Survival ◽

Growing Period ◽

Lake Outlet ◽

Salmon Fry ◽

Short Period ◽

Significant Difference ◽

Main Lake

A comparative study was made at Babine Lake, British Columbia, of the distribution, growth, and survival of sockeye salmon fry resulting from the same parental stock but reared in natural and artificial streams. Fry produced from natural spawning in the Fulton River and from eyed eggs planted in an adjacent artificial spawning channel were marked distinctively, released, and later recovered in the lake nursery area and at the lake outlet at time of seaward migration. Both groups dispersed rapidly and widely into the main lake basin and apparently mixed extensively with sockeye produced from other main lake tributaries. Lake distribution of marked fish, and the underyearling population as a whole, was not uniform nor static and the fish were concentrated in different lake areas at different times of their first growing season. River and channel fry were comparable in mean length at time of release but subsequently channel fish were smaller. Their smaller size appeared to result from late lake entry and a slower rate of growth for a short period thereafter. Over most of the growing period (June 25–October 25) rates of growth in length were similar (instantaneous daily rates of 0.00687 and 0.00737). No significant difference in survival rates of the two groups could be detected for the first 5 months of lake residence. Production of age I seaward migrants was less for river fish than for channel fish but no significance was attached to the small difference observed. These findings are discussed with respect to a fish-cultural scheme which is aimed at increasing adult production by making fuller use of the lake's capacity to rear young sockeye.

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A Natural Epizootic of Infectious Hematopoietic Necrosis in Fry of Sockeye Salmon (Oncorhynchus nerka) at Chilko Lake, British Columbia

Journal of the Fisheries Research Board of Canada ◽

10.1139/f76-196 ◽

1976 ◽

Vol 33 (7) ◽

pp. 1564-1567 ◽

Cited By ~ 33

Author(s):

Ian V. Williams ◽

Donald F. Amend

Keyword(s):

British Columbia ◽

Sockeye Salmon ◽

Virus Disease ◽

Oncorhynchus Nerka ◽

Infectious Hematopoietic Necrosis Virus ◽

Normal Range ◽

Necrosis Virus ◽

Natural Conditions ◽

Salmon Fry ◽

Infectious Hematopoietic Necrosis

The first confirmed epizootic of infectious hematopoietic necrosis virus disease under natural conditions is reported for sockeye salmon, Oncorhynchus nerka, in Chilko Lake, British Columbia. The outbreak occurred among fish of the 1972 brood during the spring of 1973. An estimated 825.6 million eggs were deposited in the Chilko River in 1972, and the production of 31.4 million fry that migrated into the lake in 1973 was significantly lower than the 55.1 million fry expected. The egg-to-fry survival of 3.8% was the lowest ever recorded at Chilko Lake (1949–73). The estimated fry-to-smolt survival of 57.1%, however, was well within the normal range for this lake. Apparently IHN severely reduced the survival of the 1972 brood of sockeye salmon fry at Chilko Lake, and all or nearly all of the reduction occurred during the egg-to-fry stage of the life cycle.

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A Comparison of Preseason Forecasting Methods for Returns of Two British Columbia Sockeye Salmon Stocks

North American Journal of Fisheries Management ◽

10.1577/1548-8675(1990)010<0046:acopfm>2.3.co;2 ◽

1990 ◽

Vol 10 (1) ◽

pp. 46-57 ◽

Cited By ~ 15

Author(s):

D. J. Noakes ◽

D. W. Welch ◽

M. Henderson ◽

E. Mansfield

Keyword(s):

British Columbia ◽

Sockeye Salmon ◽

Forecasting Methods

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Bacterioplankton, Phytoplankton, and Zooplankton Communities in a British Columbia Coastal Lake Before and After Nutrient Reduction

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f86-188 ◽

1986 ◽

Vol 43 (8) ◽

pp. 1504-1514 ◽

Cited By ~ 20

Author(s):

F. Joan Hardy ◽

Ken S. Shortreed ◽

John G. Stockner

Keyword(s):

British Columbia ◽

Sockeye Salmon ◽

Inorganic Nitrogen ◽

Size Fraction ◽

Growing Season ◽

Nutrient Reduction ◽

Nitrogen And Phosphorus ◽

Coastal Lake ◽

Before And After ◽

High Concentrations

Inorganic nitrogen and phosphorus were applied weekly during the growing season from 1980 to 1982 and twice weekly in 1983 to Hobiton Lake, a warm monomictic coastal lake in British Columbia. The lake was not fertilized in 1984. Average numbers of bacteria during the growing season decreased from a high of 1.53 × 106∙mL−1 in the fertilized condition to 0.84 × 106∙mL−1 in the unfertilized condition. Chlorophyll a concentrations decreased from a maximum seasonal average of 2.69 μg∙L−1 (1981) to 1.30 μg∙L−1 (1984), and algal numbers decreased from 5.83 × 104∙mL−1 (1983) to 2.29 × 104∙mL−1 (1984). Although the numbers of phytoplankton in each size fraction (picoplankton, nanoplankton, or microplankton) decreased in the unfertilized condition, the greatest change was an almost fourfold decrease in picoplankton, which consisted of 90% cyanobacteria (primarily Synechococcus spp.). Abundance of the large diatoms Rhizosolenia spp. and Melosira spp. increased in 1984, resulting in an increase in average seasonal algal volume. Average densities of medium (0.15–0.84 mm) and large (0.85–1.5 mm) zooplankton were greatest in 1982, while rotifers and small zooplankton (0.10–0.14 mm) were most dense in 1984 following nutrient reduction. The lake had relatively high concentrations of planktivorous juvenile sockeye salmon (Oncorhynchus nerka) that appeared to minimize any direct effect of nutrient additions on zooplankton densities.

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Orientation of Pink Salmon (Oncorhynchus gorbuscha) During Early Marine Migration from Bella Coola River System

Journal of the Fisheries Research Board of Canada ◽

10.1139/f67-188 ◽

1967 ◽

Vol 24 (11) ◽

pp. 2321-2338 ◽

Cited By ~ 9

Author(s):

M. C. Healey

Keyword(s):

British Columbia ◽

Pink Salmon ◽

River System ◽

Early Morning ◽

Oncorhynchus Gorbuscha ◽

Pink Salmon Oncorhynchus Gorbuscha ◽

Salmon Fry ◽

Marine Migration ◽

Bella Coola

During May and June 1966, the migration of pink salmon fry from the Bella Coola River was studied in Burke Channel, British Columbia. The movement of pink fry down Burke Channel was saltatory. Short periods of active migration were interspersed with longer periods when the fry did not migrate and accumulated in bays. Fry were sampled from these accumulations and their ability to orient using celestial cues was examined. During the early morning, fry tended to prefer directions at right angles to their direction of migration, but at other times of the day preferred the direction of migration. The preference for the direction of migration was strongest at midday. Fry were better oriented on clear days than on cloudy days. These data indicate that fry may use celestial cues to find directions during their oceanic migrations.

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Fecundity and Egg Retention of Some Sockeye Salmon (Oncorhynchus nerka) Stocks in British Columbia

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f86-203 ◽

1986 ◽

Vol 43 (8) ◽

pp. 1643-1655 ◽

Cited By ~ 17

Author(s):

J. I. Manzer ◽

I. Miki

Keyword(s):

British Columbia ◽

Sockeye Salmon ◽

Oncorhynchus Nerka ◽

Absolute Fecundity ◽

Egg Retention ◽

Inadequate Sample Size ◽

Egg Number ◽

The Mean ◽

The Relationship ◽

Individual Fecundity

The fecundity and egg retention of anadromous female sockeye salmon (Oncorhynchus nerka) collected during 1971–82 from several stocks in British Columbia undergoing controlled fertilization to enhance adult sockeye production were examined. The relationship between egg number and postorbital–hypural length based on 863 females representing 14 stocks was not consistent between all age-types, stocks, and years, probably because of inadequate sample size in some instances. Combined samples, however, revealed a significant positive relationship between postorbital–hypural length and egg number for age 1.2, 1.3, and 2.2 females. Mean absolute fecundity for the respective age-types was 3218, 4125, and 3544 eggs. For samples of 10 or more females, significant stock and annual differences were detected when individual mean absolute fecundity was adjusted to a postorbital–hypural length of 447 mm, but not for females of different age. A comparison of mean fecundities for coastal stocks with historical data for interior British Columbia stocks suggests that coastal stocks are 18% more fecund than interior stocks. Possible causal mechanisms for this regional difference are hypothesized. Examination of 796 carcasses (representing five stocks) for egg retention revealed a range from totally spawned to totally unspawned females, with 56% of the carcasses containing 20 eggs or less and 68% containing 50 eggs or less. The mean egg retention based on all samples combined was estimated to be 6.5% of the mean individual fecundity. This value was reduced to 3.9% when stock means were averaged.

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Importance of sample size for estimating prevalence: A case example of infectious hematopoietic necrosis viral RNA detection in mixed-stock Fraser River Sockeye salmon (Oncorhynchus nerka), British Columbia, Canada.

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2020-0279 ◽

2020 ◽

Author(s):

Emilie Laurin ◽

Julia Bradshaw ◽

Laura Hawley ◽

Ian A. Gardner ◽

Kyle A Garver ◽

...

Keyword(s):

British Columbia ◽

Sample Size ◽

Sockeye Salmon ◽

Oncorhynchus Nerka ◽

Small Sample ◽

Viral Rna ◽

Sample Sizes ◽

Apparent Prevalence ◽

Infectious Hematopoietic Necrosis ◽

Mixed Stock

Proper sample size must be considered when designing infectious-agent prevalence studies for mixed-stock fisheries, because bias and uncertainty complicate interpretation of apparent (test)-prevalence estimates. Sample size varies between stocks, often smaller than expected during wild-salmonid surveys. Our case example of 2010-2016 survey data of Sockeye salmon (Oncorhynchus nerka) from different stocks of origin in British Columbia, Canada, illustrated the effect of sample size on apparent-prevalence interpretation. Molecular testing (viral RNA RT-qPCR) for infectious hematopoietic necrosis virus (IHNv) revealed large differences in apparent-prevalence across wild salmon stocks (much higher from Chilko Lake) and sampling location (freshwater or marine), indicating differences in both stock and host life-stage effects. Ten of the 13 marine non-Chilko stock-years with IHNv-positive results had small sample sizes (< 30 samples per stock-year) which, with imperfect diagnostic tests (particularly lower diagnostic sensitivity), could lead to inaccurate apparent-prevalence estimation. When calculating sample size for expected apparent prevalence using different approaches, smaller sample sizes often led to decreased confidence in apparent-prevalence results and decreased power to detect a true difference from a reference value.

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