Comment on “Gene flow increases temporal stability of Chinook salmon (Oncorhynchus tshawytscha) populations in the Upper Fraser River, British Columbia, Canada”Appears in Can. J. Fish. Aquat. Sci. 66: 167–176.

2010 ◽  
Vol 67 (1) ◽  
pp. 202-205 ◽  
Author(s):  
Terry D. Beacham ◽  
Ruth E. Withler
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Pacific Salmon ◽  
Temporal Stability ◽  
Time Span ◽  
Population Variation ◽  
Stock Identification ◽  
Fraser River ◽  
Mixed Stock ◽  
Conservation And Management

Temporally stable genetic structure among salmonid populations has been reported in many studies, although the time span evaluated in most studies is limited to 10 years or less. This result has important implications in conservation and management of Pacific salmon ( Oncorhynchus spp.) and ramifications for the construction and application of genetic databases for stock identification of fish sampled from mixed-stock fisheries. Walter et al. (2009. Can. J. Fish. Aquat. Sci. 66: 167–176) failed to consider recent studies providing evidence that their conclusion “the overall magnitude of temporal within-population variation exceeding that of among-population variation” for the populations under study may be invalid for Fraser River Chinook salmon ( Oncorhynchus tshawytscha ) populations. Their estimation of rates and patterns of migration among Chinook salmon populations also provided results that are difficult to reconcile with published information. Evaluation of the experimental designed employed by Walter et al. (2009) indicates that their sample sizes were too small to estimate reliably genetic variation among or within populations. Extrapolation of their conclusions relating temporal instability of population structure to other Chinook salmon populations or indeed other salmonid species is unwarranted.

Individual variation in dispersal behaviour of newly emerged chinook salmon (Oncorhynchus tshawytscha) from the Upper Fraser River, British Columbia

1997 ◽  
Vol 54 (7) ◽  
pp. 1585-1592 ◽  
Author(s):  
M J Bradford ◽  
G C Taylor
Keyword(s):  
British Columbia ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Population Variation ◽  
Fraser River ◽  
Movement Behaviour ◽  
Spawning Areas ◽  
Dispersal Distances ◽  
Stream Type ◽  
Downstream Movement

Immediately after emergence from spawning gravels, fry of stream-type chinook salmon (Oncorhynchus tshawytscha) populations from tributaries of the upper Fraser River, British Columbia, distribute themselves downstream from the spawning areas, throughout the natal stream, and into the Fraser River. We tested the hypothesis that this range in dispersal distances is caused by innate differences in nocturnal migratory tendency among individuals. Using an experimental stream channel, we found repeatable differences in downstream movement behaviour among newly emerged chinook fry. Fish that moved downstream were larger than those that held position in the channel. However, the incidence of downstream movement behaviours decreased over the first 2 weeks after emergence. We propose that the variation among individuals in downstream movement behaviour we observed leads to the dispersal of newly emerged fry throughout all available rearing habitats. Thus, between- and within-population variation in the freshwater life history observed in these populations may be caused by small differences in the behaviour of individuals.

Multivariate Morphometric Variability in Pacific Salmon: Technical Demonstration

1984 ◽  
Vol 41 (8) ◽  
pp. 1150-1159 ◽  
Author(s):  
Gary A. Winans
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Pacific Salmon ◽  
Specific Information ◽  
Data Sets ◽  
Morphometric Data ◽  
Morphometric Characters ◽  
Hatchery Stock ◽  
Mixed Stock ◽  
And Storage

A computer oriented approach to the collection and analysis of morphometric characteristics in juvenile chinook salmon (Oncorhynchus tshawytscha) is described. A three-step data collection and storage method is used whereby X–Y coordinate data for relevant morphological features on a body form are collected with a digitizing pad and used to calculate morphometric characters. To test this method, I calculated two morphometric data sets, a conventional and a truss network, and compared them by multivariate analysis in a preliminary study of growth and development in one hatchery stock of fish, and in a survey of population differences in three naturally occurring populations of chinook salmon. Technical advantages of using a digitizing pad for collecting morphometric data are demonstrated. Hatchery-reared chinook salmon showed marked changes in body shape during the period of spring smoltification when marked changes in condition factor occurred. Multivariate differences were discerned among the three Oregon coastal stocks. Truss data provided more specific information concerning shape changes in the study of early development and produced greater between-group differences in the geographic survey. The results of these preliminary analyses can be applied to problems of identifying smolt status in hatchery fish and stock origin in mixed-stock fisheries.

Gene flow increases temporal stability of Chinook salmon (Oncorhynchus tshawytscha) populations in the Upper Fraser River, British Columbia, Canada

2009 ◽  
Vol 66 (2) ◽  
pp. 167-176 ◽  
Author(s):  
Ryan P. Walter ◽  
Tutku Aykanat ◽  
David W. Kelly ◽  
J. Mark Shrimpton ◽  
Daniel D. Heath
Keyword(s):  
British Columbia ◽  
Gene Flow ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Temporal Stability ◽  
Fraser River ◽  
Effective Population ◽  
Population Sizes ◽  
Low Levels ◽  
Management And Conservation

Temporal instability in population genetic structure has significant implications for management and conservation decisions. Here, we evaluate temporal stability in five populations of Chinook salmon ( Oncorhynchus tshawytscha ) from the Upper Fraser River, British Columbia, Canada, based on estimates of temporal allelic variance and effective population size (Ne) at 11 microsatellite loci. Significant temporal variation in allele frequencies was found within individual populations sampled at 5- to 12-year intervals. Removal of migrant fish or correcting for migrants resulted in higher allelic variance or reduced Ne. Populations with higher levels of temporally consistent gene flow show reduced temporal allelic variance (i.e., reduced genetic drift) and higher Ne. This study is an important empirical example of the effect of gene flow on genetic stability and Ne. In salmonids, low straying levels may have evolved to favor local adaptation; however, we show that even such low levels of gene flow can elevate effective population sizes and preserve genetic variability. This study highlights the importance of considering gene flow acting to temporally stabilize populations, particularly small ones, and should migration be interrupted, Ne levels may decline with no obvious change in census population sizes.

scholarly journals Evaluation of methods for spawner–recruit analysis in mixed-stock Pacific salmon fisheries

2020 ◽  
Vol 77 (7) ◽  
pp. 1149-1162 ◽  
Author(s):  
Benjamin A. Staton ◽  
Matthew J. Catalano ◽  
Brendan M. Connors ◽  
Lewis G. Coggins ◽  
Michael L. Jones ◽  
...  
Keyword(s):  
State Space ◽  
Oncorhynchus Tshawytscha ◽  
Pacific Salmon ◽  
State Space Model ◽  
Reference Points ◽  
State Space Models ◽  
Space Model ◽  
Trade Offs ◽  
Salmon Fisheries ◽  
Mixed Stock

Salmon populations harvested in mixed-stock fisheries can exhibit genotypic, behavioral, and life history diversity that can lead to heterogeneity in population productivity and size. Methods to quantify this heterogeneity among populations in mixed-stock fisheries are not well-established but are critical to assessing harvest–biodiversity trade-offs when setting harvest policies. We developed an integrated, age-structured, state-space model that allows for more complete use of available data and sharing of information than simpler methods. We compared a suite of state-space models of varying structural complexity to simpler regression-based approaches and, as an example case, fitted them to data from 13 Chinook salmon (Oncorhynchus tshawytscha) populations in the Kuskokwim drainage in western Alaska. We found biological and policy conclusions were largely consistent among state-space models but differed strongly from regression-based approaches. Simulation trials illustrated our state-space models were largely unbiased with respect to spawner–recruit parameters, abundance states, and derived biological reference points, whereas the regression-based approaches showed substantial bias. These findings suggest our state-space model shows promise for informing harvest policy evaluations of harvest–biodiversity trade-offs in mixed-stock salmon fisheries.

Changes in the Average Size and Average Age of Pacific Salmon

1981 ◽  
Vol 38 (12) ◽  
pp. 1636-1656 ◽  
Author(s):  
W. E. Ricker
Keyword(s):  
Growth Rate ◽  
Chinook Salmon ◽  
Sockeye Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Gill Nets ◽  
Growing Seasons ◽  
Mean Size ◽  
Average Size

Of the five species of Pacific salmon in British Columbia, chinook salmon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) are harvested during their growing seasons, while pink salmon (O. gorbuscha), chum salmon (O. keta), and sockeye salmon (O. nerka) are taken only after practically all of their growth is completed. The size of the fish caught, of all species, has decreased, but to different degrees and over different time periods, and for the most part this results from a size decrease in the population. These decreases do not exhibit significant correlations with available ocean temperature or salinity series, except that for sockeye lower temperature is associated with larger size. Chinook salmon have decreased greatly in both size and age since the 1920s, most importantly because nonmaturing individuals are taken by the troll fishery; hence individuals that mature at older ages are harvested more intensively, which decreases the percentage of older ones available both directly and cumulatively because the spawners include an excess of younger fish. Other species have decreased in size principally since 1950, when the change to payment by the pound rather than by the piece made it profitable for the gill-netters to harvest more of the larger fish. Cohos and pinks exhibit the greatest decreases, these being almost entirely a cumulative genetic effect caused by commercial trolls and gill nets removing fish of larger than average size. However, cohos reared in the Strait of Georgia have not decreased in size, possibly because sport trolling has different selection characteristics or because of the increase in the hatchery-reared component of the catch. The mean size of chum and sockeye salmon caught has changed much less than that of the other species. Chums have the additional peculiarity that gill nets tend to take smaller individuals than seines do and that their mean age has increased, at least between 1957 and 1972. That overall mean size has nevertheless decreased somewhat may be related to the fact that younger-maturing individuals grow much faster than older-maturing ones; hence excess removal of the smaller younger fish tends to depress growth rate. Among sockeye the decrease in size has apparently been retarded by an increase in growth rate related to the gradual cooling of the ocean since 1940. However, selection has had two important effects: an increase in the percentage of age-3 "jacks" in some stocks, these being little harvested, and an increase in the difference in size between sockeye having three and four ocean growing seasons, respectively.Key words: Pacific salmon, age changes, size changes, fishery, environment, selection, heritability

Production of germline transgenic Pacific salmonids with dramatically increased growth performance

1995 ◽  
Vol 52 (7) ◽  
pp. 1376-1384 ◽  
Author(s):  
Robert H. Devlin ◽  
Timothy Y. Yesaki ◽  
Edward M. Donaldson ◽  
Shao Jun Du ◽  
Choy-Leong Hew
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Cutthroat Trout ◽  
Transgenic Fish ◽  
Somatic Tissue ◽  
Growth Enhancement ◽  
Gene Construct ◽  
Average Size

Transgenic Pacific salmon have been produced by microinjection of a DNA construct consisting of chinook salmon (Oncorhynchus tshawytscha) growth hormone sequences driven by an ocean pout (Macrozoarces americanus) antifreeze protein promoter. This construct was retained in approximately 4% of fish derived from injected eggs, and resulted in dramatic enhancement of growth relative to controls. For coho salmon (O. kisutch) at 15 months of age, the average size of transgenic fish was more than 10-fold that of controls, with the largest fish more than 30-fold larger than nontransgenic siblings. Dramatic growth enhancement was also observed in transgenic rainbow trout (O. mykiss), cutthroat trout (O. clarki), and chinook salmon using this same gene construct. Transgenic coho salmon underwent precocious parr–smolt transformation during their first fall, approximately 6 months in advance of their nontransgenic siblings. At 2 years of age, five male transgenic coho salmon became sexually mature, and four of these transmitted the gene construct to sperm, the negative fish being transgenic in blood but not fin tissue. These results show that while some fish are mosaic for the gene construct in different tissues, most are transgenic in both germline and somatic tissue.

Separable Virtual Population Analysis of Pacific Salmon with Application to Marked Chinook Salmon, Oncorhynchus tshawytscha, from California's Central Valley

1987 ◽  
Vol 44 (6) ◽  
pp. 1213-1220 ◽  
Author(s):  
Robert G. Kope
Keyword(s):  
Chinook Salmon ◽  
Goodness Of Fit ◽  
Oncorhynchus Tshawytscha ◽  
Pacific Salmon ◽  
Population Analysis ◽  
Central Valley ◽  
Virtual Population Analysis ◽  
Virtual Population ◽  
California's Central Valley ◽  
California’S Central Valley

A separable virtual population analysis model is developed for Pacific salmon which utilizes aged catch and spawning escapement data. This model is applied to marked chinook salmon, Oncorhynchus tshawytscha, from California's Central Valley hatcheries using weighted least squares criteria for goodness of fit. Structural inadequacies of the model apparently produce discrepancies between predicted values and observed data that are of about the same magnitude as the observational errors in estimating the recoveries of marked fish. Some of the inadequacy of the model may be due to environmentally induced variability in population parameters, but for the marked fish used in this analysis, some of the variability is probably due to year-to-year variability in hatchery practices. From this analysis it appears that although nominal fishing effort has been relatively stable or even declining in recent years, fishing mortality has been increasing with the exception of 1983 and 1984.

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