Biochemical Genetic Comparison of Sockeye Salmon and Kokanee, the Anadromous and Nonanadromous forms of Oncorhynchus nerka

1989 ◽  
Vol 46 (1) ◽  
pp. 149-158 ◽  
Author(s):  
Chris J. Foote ◽  
Chris C. Wood ◽  
Ruth E. Withler
Keyword(s):  
Gene Flow ◽  
Genetic Similarity ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Genetic Lineages ◽  
Sympatric Forms ◽  
Biochemical Genetic ◽  
Lake Systems ◽  
Genetic Characters ◽  
Genetic Comparison

Twenty-three anadromous (sockeye salmon) and nonanadromous (kokanee) Oncorhynchus nerka populations were sampled from throughout British Columbia and examined electrophoretically at three to five polymorphic loci to test whether the forms represent distinct genetic lineages or whether they are polyphyletic. Sockeye and kokanee which spawn sympatrically in three different lake systems were also examined to determine whether the two forms belong to a single panmictic population. Our results support the hypothesis that sockeye and kokanee are polyphyletic. No genetic characters were found by which the forms could be separated consistently. Greater differences exist among O. nerka populations from different drainages than between sockeye and kokanee forms. Sympatric sockeye and kokanee were significantly different in all systems examined, demonstrating that genetic differences can persist in the absence of geographic barriers to gene flow. While sympatric sockeye and kokanee were genetically divergent, they showed greater genetic similarity to one another (in allele frequency and/or allele types) than they did to their own forms in neighbouring lakes. We argue that this genetic similarity between sympatric forms is the result of sympatric divergence of sockeye and kokanee.

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.

On the developmental pathway to nonanadromy in sockeye salmon, Oncorhynchus nerka

1994 ◽  
Vol 72 (3) ◽  
pp. 397-405 ◽  
Author(s):  
Chris J. Foote ◽  
Ian Mayer ◽  
Chris C. Wood ◽  
W. Craig Clarke ◽  
J. Blackburn
Keyword(s):  
Gene Flow ◽  
Seasonal Cycle ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Rapid Development ◽  
Inhibitory Effect ◽  
Developmental Pathway ◽  
Early Maturation ◽  
Recent Gene Flow ◽  
And Migration

The evolution of nonanadromous forms of salmonids has been linked to adaptive similarities between migration to the sea and migration to lakes, and to inhibition of smoltification by rapid development rates and early maturation. We examined the seasonal cycle of seawater adaptability in a landlocked (10 000 years) population of kokanee, Oncorhynchus nerka, to determine if the typical anadromous cycle persists in the absence of recent gene flow from sockeye salmon, as would be expected if components of smoltification are beneficial to a lacustrine existence. We also monitored the effects of maturation on seawater adaptability, to determine if they had an inhibitory effect on smoltification, as would be expected if a developmental conflict was responsible for the evolution of nonanadromous forms. Maturation was measured through the growth of gonadal tissue and the increase in circulating testosterone and 11-ketotestosterone. Landlocked kokanee showed the seawater adaptability cycle typical of sockeye salmon, and maturation had no inhibitory effect on seawater adaptability until near, or at, full maturity. We conclude that at least some components of smoltification must be beneficial to a life in lakes to account for the continued maintenance of the cycle. Further, rapid development and maturation on their own do not appear to account for the evolution of nonanadromous populations of O. nerka.

Rheotactic response of fry from beach-spawning populations of sockeye salmon: evolution after selection is relaxed

1998 ◽  
Vol 76 (12) ◽  
pp. 2186-2193 ◽  
Author(s):  
Jay E Hensleigh ◽  
Andrew P Hendry
Keyword(s):  
Gene Flow ◽  
Genetic Drift ◽  
Sockeye Salmon ◽  
Water Movement ◽  
Random Genetic Drift ◽  
River Population ◽  
Selection For ◽  
Behavioral Divergence ◽  
Lake Systems ◽  
Beach Environment

Rheotactic response was quantified for newly emerged sockeye salmon (Oncorhynchus nerka) fry from a beach population (Pleasure Point) and from an adjacent inlet population (Cedar River). The Pleasure Point population was small in number and had been established by straying from the much larger Cedar River population no more than 13 generations previously. When tested in laboratory raceways, fry from the Cedar River population were displaced downstream in the dark but not in the light. Such behavior is typical of inlet populations and presumably reflects selection for rapid movement to rearing lakes with minimal losses to predation. Fry from the Pleasure Point population showed greater downstream displacement than the Cedar River fry. Behavioral divergence of the Pleasure Point population could not be explained by selection, because water movement was absent from the beach environment. Genetic drift appeared to be a more plausible divergence mechanism. We suggest that the rheotactic response of beach populations should reflect the founding genotypes, gene flow from other populations, and random genetic drift. The results of previously published studies on the rheotactic response of beach fry in two other lake systems qualitatively support our hypothesis.

Use of Biochemical Genetic Variants for Identification of Sockeye Salmon (Oncorhynchus nerka) Stocks in Cook Inlet, Alaska

1980 ◽  
Vol 37 (8) ◽  
pp. 1236-1247 ◽  
Author(s):  
W. S. Grant ◽  
G. B. Milner ◽  
P. Krasnowski ◽  
F. M. Utter
Keyword(s):  
Genetic Variation ◽  
Genetic Variants ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Maximum Likelihood Estimates ◽  
Starch Gel Electrophoresis ◽  
Cook Inlet ◽  
Allelic Frequencies ◽  
Spawning Areas ◽  
Biochemical Genetic

We used the geographic distributions of biochemical genetic variants in sockeye salmon (Oncorhynchus nerka) to describe features of its population structure and to identify stocks in commercial catches from the central fishing district of Cook Inlet, Alaska. Allelic frequencies for 6 polymorphic loci were determined for samples of 13 spawning areas using starch gel electrophoresis and were used as the basis of stock classification. The level of genetic variation, estimated by average heterozygosity, was 4.6%. Likelihood ratio tests for heterogeneity among allelic frequencies indicated a significant degree of heterogeneity among spawning areas within the Susitna and Kenai rivers, but not among the spawning areas within the Kasilof River. These tests also indicated that for the Kasilof River, where multi-year samples were taken, allelic frequencies were not significantly different for two consecutive years. Cluster analysis of genetic similarities between samples indicated that the samples from the Kasilof River were distinct from samples of the Kenai and Susitna rivers, but that Kenai and Susitna River samples were not distinct from one another. Maximum likelihood estimates of the stock composition of samples collected from the set- and drift-gillnet fisheries were made on a weekly basis during the commercial fishing season. These estimates indicated that Susitna River fish predominated in the 1976 run into Cook Inlet.Key words: sockeye salmon, Oncorhynchus nerka; stock identification, biochemical genetic variation, population genetics, Cook Inlet, electrophoresis

Genetic Differentiation of Subpopulations of Sockeye Salmon (Oncorhynchus nerka) Within Lakes of Alaska, British Columbia, and Kamchatka, Russia

1994 ◽  
Vol 51 (S1) ◽  
pp. 147-157 ◽  
Author(s):  
Nataly V. Varnavskaya ◽  
Chris C. Wood ◽  
Rebecca J. Everett ◽  
Richard L. Wilmot ◽  
Vladimir S. Varnavsky ◽  
...  
Keyword(s):  
Genetic Differentiation ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
The United States ◽  
Allelic Frequency ◽  
Significant Heterogeneity ◽  
Frequency Data ◽  
Spawning Habitat ◽  
Lake Systems ◽  
Spawning Sites

Genetic differentiation among subpopulations of sockeye salmon (Oncorhynchus nerka) was investigated within nine intensively sampled lake systems located throughout the species' range using allozyme allelic frequency data collected by researchers in Canada, Russia, and the United States. Allelic frequencies at up to nine highly polymorphic loci were used to examine genetic diversity among 163 samples collected from 68 distinct spawning sites and to identify subpopulation structure within lakes. Significant heterogeneity was detected among sites within all lakes. The greatest differentiation was evident among subpopulations exhibiting different run timing (earlier vs. later) or utilizing different spawning habitat (tributary vs. littoral). These findings indicate that sockeye home precisely to natal streams, not just to lake systems, and underscore the importance of conserving individual spawning sites within sockeye populations.

scholarly journals Genetic variation in the feral horses of the Namib Desert, Namibia

2001 ◽  
Vol 72 (1) ◽  
Author(s):  
E.G. Cothran ◽  
E. Van Dyk ◽  
F.J. Van der Merwe
Keyword(s):  
Genetic Variation ◽  
Population Size ◽  
Genetic Similarity ◽  
Small Population ◽  
Domestic Horse ◽  
Namib Desert ◽  
Feral Horses ◽  
Founding Population ◽  
Biochemical Genetic ◽  
Genetic Comparison

Genetic variation at 7 blood-group and 10 biochemical genetic loci was examined in 30 horses from a feral herd from the Namib Desert of Namibia, Africa. The observed genetic variability was extremely low compared with that found in domestic horse breeds. The low variation was most probably a result of recent small population size and a small founding population size. Genetic comparison of the Namib horses, which were of unknown origins, to domestic horse breeds, showed that the Namib horses had the highest genetic similarity to Arabian type horses, although they did not closely resemble this type of horse in conformation.

Resumption of anadromy or straying? Origins of Sockeye Salmon Oncorhynchus nerka in the Elwha River

2021 ◽  
Author(s):  
Thomas P. Quinn ◽  
George R. Pess ◽  
Ben J.G. Sutherland ◽  
Samuel J. Brenkman ◽  
Ruth E. Withler ◽  
...  
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Elwha River

Alternative Recruitment Models of Adams River Sockeye Salmon, Oncorhynchus nerka

1987 ◽  
Vol 44 (9) ◽  
pp. 1551-1561 ◽  
Author(s):  
Jeremy S. Collie ◽  
Carl J. Walters
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Status Quo ◽  
Management Policy ◽  
Best Management ◽  
Interaction Terms ◽  
Ricker Model ◽  
The Status ◽  
Stock Recruitment ◽  
High Yields

Despite evidence of depensatory interactions among year-classes of Adams River sockeye salmon (Oncorhynchus nerka), the best management policy is one of equal escapement for all year-classes. We fit alternative models (Ricker model and Larkin model) to 32 yr of stock–recruitment data and checked, using simulation tests, that the significant interaction terms in the Larkin model are not caused by biases in estimating the parameters. We identified a parameter set (Rationalizer model) for which the status quo cyclic escapement policy is optimal, but this set fits the observed data very poorly. Thus it is quite unlikely that the Rationalizer model is correct or that the status quo escapement policy is optimal. Using the fitted stock–recruitment parameters, we simulated the sockeye population under several management policies. The escapement policy optimal under the Ricker model is best overall because of the high yields if it should be correct. If the three stock–recruitment models are equally likely to be correct, the simulations predict that adopting a constant-escapement policy would increase long-term yield 30% over the current policy and that an additional 15% increase in yield could be obtained if the policy were actively adaptive.

Reduced growth in wild juvenile sockeye salmon Oncorhynchus nerka infected with sea lice

2017 ◽  
Vol 91 (1) ◽  
pp. 41-57 ◽  
Author(s):  
S. C. Godwin ◽  
L. M. Dill ◽  
M. Krkošek ◽  
M. H. H. Price ◽  
J. D. Reynolds
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Sea Lice
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