Exceptions to semelparity: postmaturation survival, morphology, and energetics of male chinook salmon (Oncorhynchus tshawytscha)

Between 2.1 and 6.8% of fall-run male chinook salmon (Oncorhynchus tshawytscha) reared in two New Zealand hatcheries matured as yearling parr, of similar size to immature siblings. The incidence of mature parr in 58 half-sib families ranged from 0 to 69% of the available males. Although chinook salmon are normally semelparous, about 80% of mature parr survived to mature again at age 2, and all fish held for another year matured again at age 3. All three ages produced milt that successfully fertilized eggs. Morphological development in mature parr and repeat-maturing males was consistent with that of older, first time maturing males. The gonadosomatic index for mature age-2 males was 11.7, 7.2, and 5.4% for repeat-maturing males, freshwater-reared males, and sea-run males, respectively. Muscle energy density for repeat-maturing males (4.45 kJ/g) was lower than for normal males (5.20-5.45 kJ/g) and negatively correlated with the gonadosomatic index. Although we think it unlikely that repeat maturation occurs regularly in the wild, our results indicate that under favorable conditions, chinook salmon can exhibit some iteroparous traits. We hypothesize an evolutionary continuum between semelparity and iteroparity in salmonids, primarily characterized by modifications in a few key energetic and physiological thresholds.

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Within-river straying: sex and size influence recovery location of hatchery Chinook salmon (Oncorhynchus tshawytscha)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2018-0384 ◽

2020 ◽

Vol 77 (2) ◽

pp. 226-235 ◽

Cited By ~ 1

Author(s):

Amanda M.M. Pollock ◽

Maryam Kamran ◽

Andrew H. Dittman ◽

Marc A. Johnson ◽

David L.G. Noakes

Keyword(s):

River Basin ◽

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Classification Tree ◽

River System ◽

Classification Tree Analysis ◽

Spawning Grounds ◽

Natural Origin ◽

Elk River ◽

In The Wild

Salmon straying is often defined as the failure of adults to return to their natal river system. However, straying within a river basin can be problematic if hatchery salmon do not return to their hatchery of origin and subsequently spawn in the wild with natural-origin salmon. We examined within-river straying patterns from 34 years of coded-wire tag data, representing 29 941 hatchery fall Chinook salmon (Oncorhynchus tshawytscha) in the Elk River, Oregon, USA. Using classification tree analysis, we found that females and larger salmon were more likely to be recovered on the spawning grounds than males and smaller fish. Females larger than 980 mm had a 51.6% likelihood of recovery on the spawning grounds rather than at the Elk River Hatchery. Our findings raise questions about the behavior of straying adults and implications for management of these stocks, with a focus on methods to reduce within-river straying. We recommend further studies to determine whether carcass recoveries are fully representative of hatchery salmon that stray within the Elk River basin.

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Differences in egg quantity and quality among hatchery- and wild-origin Chinook salmon (Oncorhynchus tshawytscha)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2015-0083 ◽

2016 ◽

Vol 73 (5) ◽

pp. 737-746 ◽

Cited By ~ 3

Author(s):

Michaela W. Haring ◽

Tom A. Johnston ◽

Murray D. Wiegand ◽

Aaron T. Fisk ◽

Trevor E. Pitcher

Keyword(s):

Stable Isotopes ◽

Adult Development ◽

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Neutral Lipids ◽

Fatty Acid Content ◽

Reproductive Investment ◽

Gonadal Development ◽

Gonad Mass ◽

In The Wild

Each year, millions of hatchery-raised juvenile salmon are released into the wild to help bolster salmon populations all over North America. These fish often differ from their wild-origin conspecifics in terms of survival and reproductive success after release, but our understanding of their reproductive investment is limited. We examined differences in egg number (gonad mass and fecundity) and quality (mass, lipids, fatty acids) between spawning hatchery- and wild-origin Chinook salmon (Oncorhynchus tshawytscha) from Lake Ontario. Hatchery-origin females were found to not differ significantly in body size, age, egg total lipids, and fatty acid content of eggs relative to wild-origin females, but hatchery-origin females allocated significantly less body mass and neutral lipids into egg and gonadal development compared with wild-origin females. We also examined diets of both groups of females using stable isotopes and found that carbon and nitrogen stable isotopes suggested limited differences in the diet between hatchery- and wild-origin adult females. The results from the present study provide evidence that the differing environmental conditions and associated selection pressures of captive environments during early life in hatchery settings can alter certain life-history traits later in adult development, namely gonad mass and egg size, and could contribute to differences in their performance in the wild.

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Egg size, fecundity, and development rate of two introduced New Zealand chinook salmon (Oncorhynchus tshawytscha) populations

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f98-074 ◽

1998 ◽

Vol 55 (8) ◽

pp. 1946-1953 ◽

Cited By ~ 50

Author(s):

Michael T Kinnison ◽

Martin J Unwin ◽

William K Hershberger ◽

Thomas P Quinn

Keyword(s):

New Zealand ◽

Chinook Salmon ◽

Egg Size ◽

Oncorhynchus Tshawytscha ◽

Gonadosomatic Index ◽

Phenotypic Traits ◽

Egg Weight ◽

Phenotypic Differences ◽

Development Rates ◽

Temperature Records

Interpopulation differences in several adult phenotypic traits suggest that New Zealand (NZ) chinook salmon (Oncorhynchus tshawytscha) are evolving into distinct populations. To further investigate this hypothesis, we compared egg sizes, fecundities, and early development rates of chinook from two NZ streams. The two NZ study populations differed in size-adjusted egg weight and gonadosomatic index, but not in size-adjusted fecundity. Egg weight, fecundity, and gonadosomatic index values for both NZ populations were different than values for chinook from Battle Creek, California, the population regarded as the ancestral NZ stock. In contrast, there was little evidence of divergence in juvenile development. Time to hatching did not differ between the two NZ study populations and heritability estimates were small with large standard errors. Evidence of a small difference in alevin growth rate may have represented an effect of yolk conversion mechanics related to egg size. Despite the similarity in development rates under shared conditions, modeling based on temperature records suggests that emergence dates in the two NZ streams may differ by 4-6 weeks, yielding significant phenotypic differences.

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Identifying the contribution of wild and hatchery Chinook salmon (Oncorhynchus tshawytscha) to the ocean fishery using otolith microstructure as natural tags

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f07-129 ◽

2007 ◽

Vol 64 (12) ◽

pp. 1683-1692 ◽

Cited By ~ 44

Author(s):

Rachel Barnett-Johnson ◽

Churchill B Grimes ◽

Chantell F Royer ◽

Christopher J Donohoe

Keyword(s):

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Wild Fish ◽

Otolith Microstructure ◽

Exogenous Feeding ◽

Daily Growth ◽

Wild Salmon ◽

Growth Increments ◽

In The Wild ◽

Mixed Stock

Quantifying the contribution of wild (naturally spawned) and hatchery Chinook salmon (Oncorhynchus tshawytscha) to the mixed-stock ocean fishery is critical to understanding their relative importance to the persistence of salmon stocks. The inability to distinguish hatchery and wild salmon has inhibited the detection of declines or recoveries for many wild populations. By using Chinook salmon of known hatchery and wild origin, we established a baseline for separating these two sources using otolith microstructure. Otoliths of wild salmon contained a distinct exogenous feeding check likely reflecting an abrupt transition in food resources from maternal yolk not experienced by fish reared in hatcheries. Daily growth increments in otoliths from hatchery salmon immediately after the onset of exogenous feeding were wider and more uniform in width than those in wild fish. The discriminant function that we used to distinguish individuals reared in hatcheries or in the wild was robust between years (1999 and 2002), life history stages (juveniles and adults), and geographic regions (California, British Columbia, and Alaska) and classified fish with ~91% accuracy. Results from our mixed-stock model estimated that the contribution of wild fish was 10% ± 6%, indicating hatchery supplementation may be playing a larger role in supporting the central California coastal fishery than previously assumed.

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Chemical alarm signals and complex hatchery rearing habitats affect antipredator behavior and survival of chinook salmon (Oncorhynchus tshawytscha) juveniles

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f99-010 ◽

1999 ◽

Vol 56 (5) ◽

pp. 830-838 ◽

Cited By ~ 107

Author(s):

Barry A Berejikian ◽

R Jan F. Smith ◽

E Paul Tezak ◽

Steven L Schroder ◽

Curtis M Knudsen

Keyword(s):

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Antipredator Behavior ◽

Cutthroat Trout ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Negative Effect ◽

In The Wild ◽

Antipredator Behaviors ◽

Chemical Stimuli ◽

Predator Odour

The present study examined the effects of chemical antipredator conditioning on antipredator behavior and the relative effects of antipredator conditioning and seminatural rearing environments on postrelease survival of chinook salmon (Onocrhynchus tshawytscha). Hatchery-reared juvenile chinook salmon were exposed to extracts from conspecific tissue or to comparable stimuli from green swordtail (Xiphophorus helleri). These "injured fish" stimuli were paired with water that contained the odour of predatory cutthroat trout (Oncorhynchus clarki). Chinook salmon receiving conspecific stimuli showed higher levels of several antipredator behaviors compared with chinook salmon receiving green swordtail extracts. When the two groups of chinook salmon were tested 2 days later with cutthroat trout stimulus alone, the chinook salmon that had originally received injured conspecific stimuli paired with cutthroat trout odour spent more time motionless than chinook salmon that had received green swordtail stimuli and cutthroat trout odour. In another experiment, complex rearing treatments had a negative effect on instream survival (contrary to previous studies) that was compensated for by the application of the chinook salmon extract and cutthroat trout odour prior to release. Chinook salmon, like rainbow trout (Oncorhynchus mykiss), show antipredator behavior in response to chemical stimuli from injured conspecifics and learn predator recognition when such stimuli are paired with predator odour, improving survival in the wild.

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Variation of Y-chromosome DNA markers in Chinook salmon (Oncorhynchus tshawytscha) populations

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f05-048 ◽

2005 ◽

Vol 62 (6) ◽

pp. 1386-1399 ◽

Cited By ~ 24

Author(s):

R H Devlin ◽

L Park ◽

D M Sakhrani ◽

J D Baker ◽

A R Marshall ◽

...

Keyword(s):

Y Chromosome ◽

Chinook Salmon ◽

Dna Markers ◽

Oncorhynchus Tshawytscha ◽

Chromosome Structure ◽

Single Copy ◽

Structural Variants ◽

Sex Marker ◽

High Incidence ◽

Normal Males

Two Y-chromosome DNA markers (a repetitive sequence, OtY1, and a single-copy marker, GH-Y) tightly linked to the sex-determination locus have been examined for their association with sexual development among 55 populations of Chinook salmon (Oncorhynchus tshawytscha) from the Yukon, British Columbia, Washington, Oregon, and Idaho. Normal linkage has been observed in 96.7% of 2478 individuals examined. Only five males (0.44%) were found lacking both markers (none from Canadian systems), and 14 females (1.04%) from US populations and two females (0.15%) from Canadian populations were found to possess both markers. Variants identified included weakly amplifying alleles for GH-Y and OtY1 and structural variants identified by Southern-blot analysis. The frequency of variants in males was more than 2-fold that in females, and males deficient in GH-Y were more common (3.6%) than males deficient in the repetitive OtY1 sequence (0.7%). Some individuals (of both sexes) possessed fewer copies of the OtY1 repeat than normal males, revealing molecular dynamics that alter Y-chromosome structure within and among populations. A population (Hanford Reach) previously reported as having a high incidence of females possessing the OtY1 marker, and suspected of being sex-reversed, was found to have normal sex-marker genotypes in the present study.

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Relationships between heterozygosity, allelic distance (d2), and reproductive traits in chinook salmon, Oncorhynchus tshawytscha

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f01-192 ◽

2002 ◽

Vol 59 (1) ◽

pp. 77-84 ◽

Cited By ~ 40

Author(s):

Daniel D Heath ◽

Colleen A Bryden ◽

J Mark Shrimpton ◽

George K Iwama ◽

Joanne Kelly ◽

...

Keyword(s):

Genetic Variation ◽

Chinook Salmon ◽

Regression Models ◽

Oncorhynchus Tshawytscha ◽

Gonadosomatic Index ◽

Reproductive Traits ◽

Reproductive Fitness ◽

Egg Survival ◽

Allele Size ◽

Multivariate Relationships

Correlations of various measures of individual genetic variation with fitness have been reported in a number of taxa; however, the genetic nature of such correlations remains uncertain. To explore this, we mated 100 male and 100 female chinook salmon (Oncorhynchus tshawytscha) in a one-to-one breeding design and quantified reproductive fitness and allocation (male gonadosomatic index, GSI; female fecundity; egg size; egg survival). Each fish was scored for allele size at seven microsatellite loci. We applied univariate and multivariate regression models incorporating two genetic variation statistics (microsatellite heterozygosity and squared allelic distance, d2) with reproductive parameters. The majority of the relationships were found to be nonsignificant; however, we found significant, positive, univariate relationships for fecundity and GSI (25% of tests) and significant, multivariate relationships at individual loci for all four traits (13% of tests). One microsatellite locus, Omy207, appeared to be closely associated with reproductive fitness in female chinook salmon (but not male), based on the multivariate analysis. Although direct tests for overdominance versus inbreeding effects proved inconclusive, our data are consistent with the presence of both inbreeding (general) and overdominance (local) effects on reproductive traits in chinook salmon.

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