Patterns of covariation in survival rates of British Columbian and Alaskan sockeye salmon (Oncorhynchus nerka) stocks

1998 ◽  
Vol 55 (11) ◽  
pp. 2503-2517 ◽  
Author(s):  
Randall M Peterman ◽  
Brian J Pyper ◽  
Michael F Lapointe ◽  
Milo D Adkison ◽  
Carl J Walters
Keyword(s):  
Survival Rate ◽  
Sockeye Salmon ◽  
Spatial Scales ◽  
Oncorhynchus Nerka ◽  
Survival Rates ◽  
Ocean Basin ◽  
Similar Response ◽  
Fraser River ◽  
Bristol Bay ◽  
Basin Scale

We used a multi-stock comparison to identify spatial and temporal characteristics of environmentally driven sources of variability across four decades in the productivity of 29 sockeye salmon (Oncorhynchus nerka) stocks from British Columbia (B.C.) and Alaska. We examined patterns of covariation among indices of survival rate (residuals from the best-fit stock-recruitment curve) and found positive covariation among Fraser River sockeye stocks (southern B.C.) and, to a greater extent, among Bristol Bay stocks (western Alaska) but no evidence of covariation between these two regions or with stocks of other regions in B.C. and Alaska. This indicates that important environmental processes affecting variation in sockeye survival rate from spawners to recruits operate at regional spatial scales, rather than at the larger, ocean-basin scale. The observed covariation in survival rates of Bristol Bay stocks appears to be due to a combination of both freshwater and, to a greater degree, marine processes. Bristol Bay sockeye stocks showed a dramatic and persistent increase in survival rates coinciding with the abrupt changes in the North Pacific environment in the mid-1970s; however, there was little evidence of a similar response for Fraser River stocks.

A widespread decrease in productivity of sockeye salmon (Oncorhynchus nerka) populations in western North America

2012 ◽  
Vol 69 (8) ◽  
pp. 1255-1260 ◽  
Author(s):  
Randall M. Peterman ◽  
Brigitte Dorner
Keyword(s):  
Sockeye Salmon ◽  
Spatial Scales ◽  
Oncorhynchus Nerka ◽  
Geographic Area ◽  
Fraser River ◽  
Western North America ◽  
Southeast Alaska ◽  
The Past ◽  
Large Geographic Area ◽  
Marine Areas

We used data on 64 stocks of sockeye salmon ( Oncorhynchus nerka ) from British Columbia (B.C.), Washington, and Alaska to determine whether recent decreases in abundance and productivity observed for Fraser River, B.C., sockeye have occurred more widely. We found that decreasing time trends in productivity have occurred across a large geographic area ranging from Washington, B.C., southeast Alaska, and up through the Yakutat peninsula, Alaska, but not in central and western Alaska. Furthermore, a pattern of predominantly shared trends across southern stocks and opposite trends between them and stocks from western Alaska was present in the past (1950–1985), but correlations have intensified since then. The spatial extent of declining productivity of sockeye salmon has important implications for management as well as research into potential causes of the declines. Further research should focus on mechanisms that operate at large, multiregional spatial scales, and (or) in marine areas where numerous correlated sockeye stocks overlap.

Spatial covariation in survival rates of Northeast Pacific pink salmon (Oncorhynchus gorbuscha)

2001 ◽  
Vol 58 (8) ◽  
pp. 1501-1515 ◽  
Author(s):  
Brian J Pyper ◽  
Franz J Mueter ◽  
Randall M Peterman ◽  
David J Blackbourn ◽  
Chris C Wood
Keyword(s):  
Spatial Scales ◽  
Pink Salmon ◽  
Survival Rates ◽  
Ocean Basin ◽  
Oncorhynchus Gorbuscha ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Geographical Regions ◽  
Basin Scale ◽  
Stock Recruitment ◽  
Best Fit

We examined spatial patterns of covariation in indices of survival rate (residuals from the best-fit stock- recruitment curve) across four decades among 43 wild pink salmon (Oncorhynchus gorbuscha) stocks from 14 geographical regions in Washington, British Columbia, and Alaska. We found strong evidence of positive covariation among stocks within each region and between certain adjacent regions (e.g., correlations from 0.3 to 0.7) but no evidence of covariation between stocks of distant regions (e.g., separated by 1000 km or more). This suggests that important environmental processes affecting temporal variation in survival rates of pink salmon from spawners to recruits operate at regional spatial scales rather than at the larger ocean basin scale. Based on limited fry abundance data, we found that this covariation in spawner-to-recruit survival rates may be strongly influenced by marine processes.

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.

Retrospective analysis of harvest management performance for Bristol Bay and Fraser River sockeye salmon (Oncorhynchus nerka)

2008 ◽  
Vol 65 (3) ◽  
pp. 409-424 ◽  
Author(s):  
Steven J.D. Martell ◽  
Carl J Walters ◽  
Ray Hilborn
Keyword(s):  
Key Management ◽  
Sockeye Salmon ◽  
Current Knowledge ◽  
Oncorhynchus Nerka ◽  
Total Yield ◽  
Fraser River ◽  
Harvest Management ◽  
Bristol Bay ◽  
Stock Size ◽  
Spawning Stock

Given current knowledge of mean stock–recruitment relationships and variation in past recruitment, yield of sockeye salmon (Oncorhynchus nerka) in Bristol Bay, Alaska, and Fraser River, British Columbia, might have been at least 100%–300% larger since 1950 than was actually achieved. Most of these gains would have been due to knowledge of optimum mean spawning stock size rather than specific recruitment anomalies; knowing all future recruitment anomalies at the time of each spawning stock choice would have likely only added 2%–5% to total catches. For some stocks, delayed density dependence (cyclic dominance) might have resulted in somewhat lower yields, but under optimal management would still have been higher than were achieved. Even given only estimates of optimum spawning stock size each year based on data available as of that year, but following fixed escapement harvest policy rules, managers could likely have achieved 30%–40% higher total yield. Key management experiments for the future will involve testing for cyclic dominance effects on two major stocks (Kvichak, Late Shuswap) to determine whether stocks with strong, delayed, density-dependent survival effects should be deliberately managed through fallow rotation strategies for juvenile nursery lakes.

Freshwater and marine migration and survival of endangered Cultus Lake sockeye salmon (Oncorhynchus nerka) smolts using POST, a large-scale acoustic telemetry array

2009 ◽  
Vol 66 (5) ◽  
pp. 736-750 ◽  
Author(s):  
David W. Welch ◽  
Michael C. Melnychuk ◽  
Erin R. Rechisky ◽  
Aswea D. Porter ◽  
Melinda C. Jacobs ◽  
...  
Keyword(s):  
Sockeye Salmon ◽  
Large Scale ◽  
Oncorhynchus Nerka ◽  
Exit Time ◽  
Survival Rates ◽  
Release Site ◽  
Fraser River ◽  
Continental Scale ◽  
Marine Migration ◽  
Post Array

Freshwater and early marine migration and survival of endangered Cultus Lake sockeye ( Oncorhynchus nerka ) salmon were studied using the Pacific Ocean Shelf Tracking (POST) array. Smolts were acoustically tagged in 2004–2007, and their migration was recorded within the lower Fraser River and coastal southern British Columbia waters. Most smolts showed rapid directional movement (swimming speeds of ~15–30 km·day–1). Average exit time from the Fraser River was 4.0–5.6 days after release, and average residence time within the Strait of Georgia was 25.6–34.1 days. Most individuals migrated northward, generally close to the mainland coast. Survival rates, assessed using standard mark–recapture methods, were generally high during the downstream migration (50%–70%), except in 2005 when survival was <20%, possibly because of a late release. Marine survival rates were stable among years, between 10%–30% at a subarray sited 500 km away from the release site. Movement rates were similar to those of previously published work, but the POST array provided direct measurements of movement and estimates of survival and demonstrated the feasibility of establishing continental-scale acoustic arrays for management and conservation of marine species.

Biochemical Studies on Sockeye Salmon During Spawning Migration: XI. The Free Histidine Content of the Tissues

1960 ◽  
Vol 17 (3) ◽  
pp. 347-351 ◽  
Author(s):  
J. D. Wood ◽  
D. W. Duncan ◽  
M. Jackson
Keyword(s):  
Amino Acid ◽  
Sockeye Salmon ◽  
Alimentary Tract ◽  
Oncorhynchus Nerka ◽  
The Other ◽  
Spawning Migration ◽  
Fraser River ◽  
Initial Value ◽  
Spawning Grounds ◽  
Biochemical Studies

During the first 250 miles (400 km) of spawning migration of Fraser River sockeye salmon (Oncorhynchus nerka) the free histidine content of the muscle, alimentary tract, and head+skin+bones+tail decreased to a small fraction of the initial value. A further decrease occurred in the levels of this amino acid in the alimentary tract during the subsequent 415-mile (657-km) migration to the spawning grounds, no change being observed with the other tissues. Comparatively small changes in free histidine were found with heart, spleen, liver, kidney and gonads during migration.

Intact genetic structure and high levels of genetic diversity in bottlenecked sockeye salmon (Oncorhynchus nerka) populations of the Fraser River, British Columbia, Canada

2000 ◽  
Vol 57 (10) ◽  
pp. 1985-1998 ◽  
Author(s):  
Ruth E Withler ◽  
Khai D Le ◽  
R John Nelson ◽  
Kristina M Miller ◽  
Terry D Beacham
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Allelic Diversity ◽  
Lower Proportion ◽  
Fraser River ◽  
Rare Alleles ◽  
Genetic Bottlenecks

Analysis of six microsatellite loci in 5800 sockeye salmon (Oncorhynchus nerka) from 29 Fraser River populations provided little evidence of genetic bottlenecks or mass straying in upper Fraser sockeye salmon resulting from reduced abundances following 1913-1914 rockslides in the Fraser canyon and successive decades of high exploitation. Upper Fraser populations were not characterized by a paucity of rare alleles, a sensitive indicator of populations in which effective size has been recently reduced. Heterozygosity and allelic diversity did not differ consistently between lower and upper Fraser populations. Throughout the watershed, early-migrating populations had lower allelic diversity and a lower proportion of rare alleles than did late-migrating ones. Genetic differentiation between upper and lower Fraser populations and heterogeneity among lower Fraser populations supported the suggestion that Fraser sockeye salmon are descendants of at least two postglacial "races." Variation among lakes within regions was the strongest component of genetic structure, accounting for five times the variation among populations within lakes and more than two times the variation among regions. Extensive historical transplants of eggs and juveniles apparently resulted in lit tle gene flow among regions, but three populations were reestablished or rebuilt as the result of more recent transplants.

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