Relationship among adult body length, abundance, and ocean temperature for British Columbia and Alaska sockeye salmon (Oncorhynchus nerka), 1967–1997

1999 ◽  
Vol 56 (10) ◽  
pp. 1716-1720 ◽  
Author(s):  
Brian J Pyper ◽  
Randall M Peterman
Keyword(s):  
British Columbia ◽  
Time Series ◽  
Body Length ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Gulf Of Alaska ◽  
Reduced Body ◽  
Adult Body ◽  
Northeastern Pacific ◽  
Length Data

Body length of adult Pacific sockeye salmon (Oncorhynchus nerka) has decreased significantly in recent years. We used 69 time series of age-specific body-length data (1967-1997) for 30 sockeye salmon stocks from southern British Columbia to western Alaska to test hypotheses about the effects of oceanographic conditions and competition on growth rate of sockeye salmon. Using principal components analysis (PCA), we constructed a single time series (PC1) that represented the dominant pattern of variability in length-at-age shared among these stocks. Taking into account time trends and autocorrelation in residuals, we found that increases in total Gulf of Alaska sockeye abundance and increases in sea-surface temperature (SST) across the Gulf of Alaska were significantly associated with reduced adult body length. Abundance and SST together accounted for 71% of the variability in PC1. Although researchers have documented increases in both abundance of sockeye salmon and their food in the northeastern Pacific Ocean over the last few decades, it is possible that increased food was more than offset by increased sockeye abundance, leading to greater competition and reduced body size.

Density-Dependent Growth in Early Ocean Life of Sockeye Salmon (Oncorhynchus nerka)

1984 ◽  
Vol 41 (12) ◽  
pp. 1825-1829 ◽  
Author(s):  
Randall M. Peterman
Keyword(s):  
British Columbia ◽  
Body Size ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Management Strategies ◽  
Gulf Of Alaska ◽  
Density Dependent ◽  
Adult Body Size ◽  
Adult Body ◽  
Dependent Growth

Significant decreases in adult body size and marine growth rate occur in seven British Columbia and Bristol Bay, Alaska, sockeye salmon (Oncorhynchus nerka) stocks when large numbers of sockeye are present in the Gulf of Alaska. These density-dependent effects arise mainly during early ocean life and are probably due to competition for food. The total sockeye abundance in the Gulf of Alaska is at least as important as within-stock abundance in determining final adult body size. British Columbia sockeye show a 10–22% decrease in adult body weight at high abundance of conspecifics. Thus, future evaluations of management strategies cannot simply focus on individual stocks, but must take a broader perspective which includes other sockeye populations.

The distribution of plerocercoids of Diphyllobothrium dendriticum (Nitzsch) in sockeye salmon (Oncorhynchus nerka) smolts from Great Central Lake, British Columbia

1988 ◽  
Vol 66 (4) ◽  
pp. 850-852 ◽  
Author(s):  
Hilda Lei Ching
Keyword(s):  
British Columbia ◽  
Body Length ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Vancouver Island ◽  
Infected Fish ◽  
Mean Intensity ◽  
Diphyllobothrium Dendriticum ◽  
Pyloric Ceca

Sockeye salmon (Oncorhynchus nerka) from Great Central Lake, Vancouver Island, British Columbia, were sampled in May of 1986 and 1987 to study the locations and sizes of plerocercoids of Diphyllobothrium dendriticum. In 1986, 93% of 59 smolts were infected with a total of 222 plerocercoids (mean intensity ± SE, 4.0 ± 3.4; range, 1–15). In 1987, 77% of 168 smolts were infected with a total of 341 plerocercoids (mean ± SE, 2.6 ± 1.8; range, 1–9). More than 75% of the infected fish contained one to three plerocercoids, which were more often found free in the musculature than encysted in the viscera. Plerocercoids occurred most frequently in the midepaxial and midhypaxial musculature and encysted on the stomach and pyloric ceca. Plerocercoids varied in body length: those from the stomach area were <2 mm, and those in the viscera and musculature were 3–10 mm (a few from the musculature were >10 mm).

Cross Correlations Between Reconstructed Ocean Abundances of Bristol Bay and British Columbia Sockeye Salmon (Oncorhynchus nerka)

1984 ◽  
Vol 41 (12) ◽  
pp. 1814-1824 ◽  
Author(s):  
Randall M. Peterman ◽  
Fred Y. C Wong
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Population Analysis ◽  
Oncorhynchus Nerka ◽  
Survival Rates ◽  
Gulf Of Alaska ◽  
Time Lags ◽  
Bristol Bay ◽  
Reconstruction Methods ◽  
Cross Correlations

Anecdotal reports of a tendency for British Columbia sockeye salmon (Oncorhynchus nerka) to be low when Bristol Bay, Alaska, returns are high prompted a reconstruction of minimum abundances of sockeye resident in the Gulf of Alaska each year from the early 1950s to mid-1970s. This backwards reconstruction using Fry's virtual population analysis was done by using catch, escapement, and age structure data for each area in British Columbia and Bristol Bay. Use of more sophisticated backwards reconstruction methods was precluded by lack of age-specific annual survival rates by stock. Ocean abundances of British Columbia and Bristol Bay sockeye show significant autocorrelations at periods consistent with the cyclic dominant patterns of their largest stocks. Cross correlations at lag 0 between ocean abundances of various ages of fish from these two regions show one case of a significant inverse relation in abundances. In addition, there are significant cross correlations between British Columbia and Bristol Bay ocean abundances at various time lags, showing that cycles in their abundances are out of synchrony. This lack of synchrony persisted longer than would be expected from cyclic dominance patterns and age at maturity of British Columbia and Bristol Bay sockeye, and several alternative explanations of this asynchrony are discussed.

Patterns of covariation in length and age at maturity of British Columbia and Alaska sockeye salmon (Oncorhynchus nerka) stocks

1999 ◽  
Vol 56 (6) ◽  
pp. 1046-1057 ◽  
Author(s):  
Brian J Pyper ◽  
Randall M Peterman ◽  
Michael F Lapointe ◽  
Carl J Walters
Keyword(s):  
British Columbia ◽  
Survival Rate ◽  
Body Length ◽  
Sockeye Salmon ◽  
Large Scale ◽  
Oncorhynchus Nerka ◽  
Regional Scale ◽  
Survival Rates ◽  
Age At Maturity ◽  
Environmental Processes

We examined patterns of covariation in age-specific adult body length and in mean age at maturity among 31 sockeye salmon (Oncorhynchus nerka) stocks from western Alaska to southern British Columbia. Positive covariation in body length was prevalent across stocks of all regions (e.g., correlations (r) from 0.2 to 0.6), suggesting either that growth periods critical to final body length of sockeye salmon occur while ocean distributions of these stocks overlap or that large-scale environmental processes influence these stocks similarly while they do not overlap. We also found stronger covariation among body length of stocks within regions (r from 0.4 to 0.7), indicating that unique regional-scale processes were also important. Mean age at maturity also showed positive covariation both among and within regions, but correlations were weaker than those for length. We also examined patterns of covariation between length and mean age at maturity and between these variables and survival rate. Although length and mean age at maturity were negatively correlated, there was little evidence of covariation between these variables and survival rate, suggesting that environmental processes that influence marine survival rates of sockeye salmon are largely different from those affecting size and age at maturity.

Variants of Lactate Dehydrogenase Isozymes in Sera of Sockeye Salmon (Oncorhynchus nerka)

1969 ◽  
Vol 26 (1) ◽  
pp. 15-19 ◽  
Author(s):  
H. O. Hodgins ◽  
W. E. Ames ◽  
F. M. Utter
Keyword(s):  
British Columbia ◽  
Lactate Dehydrogenase ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Gulf Of Alaska ◽  
Bristol Bay ◽  
Lactate Dehydrogenase Isozymes ◽  
Skeena River ◽  
Total Body ◽  
Ldh Isozymes

Three phenotypes of lactate dehydrogenase (LDH) isozymes were found in sera of sockeye salmon (Oncorhynchus nerka), presumably representing B′B′, B′B, and BB genotypes. No association was obvious between LDH phenotype of sera and sex or total body length.Of 1006 sera from Asian, Bristol Bay, and Gulf of Alaska stocks, 826 were B′B′ and 180 were B′B or BB. Of 591 sera from Washington and British Columbia stocks, 589 were B′B′ and 2 were B′B; both of the B-allele phenotypes were found in fish captured at the Skeena River in northern British Columbia. These findings suggested that LDH isozymes should be useful in studies on ocean distribution of sockeye salmon and in characterizing certain Asian and Alaskan sockeye salmon populations.

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

1986 ◽  
Vol 43 (8) ◽  
pp. 1643-1655 ◽  
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.

scholarly journals 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.

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.

Infectious agent detections in archived Sockeye salmon (Oncorhynchus nerka ) samples from British Columbia, Canada (1985-94)

2019 ◽  
Vol 42 (4) ◽  
pp. 533-547 ◽  
Author(s):  
Krishna K. Thakur ◽  
Raphaël Vanderstichel ◽  
Karia Kaukinen ◽  
Omid Nekouei ◽  
Emilie Laurin ◽  
...  
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Infectious Agent

Recent Colonization of a Major Salmon-Producing Lake in British Columbia by Pacific Lamprey (Lampetra tridentata)

1984 ◽  
Vol 41 (2) ◽  
pp. 278-285 ◽  
Author(s):  
Susan P. Farlinger ◽  
Richard J. Beamish
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Nursery Area ◽  
Commercial Fishery ◽  
Rock Slide ◽  
Pacific Lamprey ◽  
Natural Lake ◽  
Lampetra Tridentata

Pacific lamprey (Lampetra tridentata) were first observed in Babine Lake, the largest natural lake wholly contained in British Columbia, in 1963 and are currently found along approximately 15% of the length of the lake near the outlet. The number of spawning adults in 1982 was estimated to be 7281. Since Babine Lake is a major nursery area for sockeye salmon (Oncorhynchus nerka), the colonization of this lake by a parasitic lamprey is of concern, particularly if the species can become nonanadromous. The colonization may be beneficial if a commercial fishery can be sustained and if the species does not begin to feed in freshwater. The reason for the recent colonization is unknown but it coincides with increased human manipulation of fishes and habitat, including the removal of a major rock slide, 65 km downstream of the lake.

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