Unnatural random mating policies select for younger age at maturity in hatchery Chinook salmon (Oncorhynchus tshawytscha) populations

2009 ◽  
Vol 66 (9) ◽  
pp. 1505-1521 ◽  
Author(s):  
David G. Hankin ◽  
Jacqueline Fitzgibbons ◽  
Yaming Chen
Keyword(s):  
Chinook Salmon ◽  
Large Scale ◽  
Oncorhynchus Tshawytscha ◽  
Random Mating ◽  
Age At Maturity ◽  
Natural Spawning ◽  
Younger Age ◽  
Selection For ◽  
Age And Sex

We explored the long-term consequences of three mating regimes ((1) completely random, (2) completely random but excluding jacks (age 2 males), and (3) male length ≥ female length) on age and sex structure of wild and hatchery populations of Chinook salmon ( Oncorhynchus tshawytscha ). Regimes similar to regimes 1 or 2 are used at most salmon hatcheries, whereas regime 3 emulates the outcomes of natural spawning behaviors that favor larger males. Inheritance of age at maturity is captured in age- and sex-structured models via matrices of age- and sex-specific conditional maturation probabilities that depend on age and sex of parents. In unexploited populations, regime 1 leads to substantial long-term selection for younger age at maturity, an effect that is somewhat reduced by regime 2, but greatly reduced under regime 3. Equilibrium age and sex structures for wild and hatchery populations under regime 3 are similar to those of natural populations, whereas mating regime 1 generates age structure that is greatly shifted toward younger ages and jacks. To prevent unintentional selection for younger age at maturity, we recommend that large-scale hatcheries replace unnatural completely random mating regimes with mating regimes that emulate the outcomes of natural spawning behaviors.

scholarly journals Phenotypic integration of behavioural and physiological traits is related to variation in growth among stocks of Chinook salmon

2018 ◽  
Vol 75 (12) ◽  
pp. 2271-2279 ◽  
Author(s):  
Mitchel G.E. Dender ◽  
Pauline M. Capelle ◽  
Oliver P. Love ◽  
Daniel D. Heath ◽  
John W. Heath ◽  
...  
Keyword(s):  
Chinook Salmon ◽  
Large Scale ◽  
Oncorhynchus Tshawytscha ◽  
Fish Growth ◽  
Life History Stage ◽  
Diel Variation ◽  
Level Variation ◽  
Stock Level ◽  
Performance Metric ◽  
Selection For

The selection for a single organismal trait like growth in breeding programs of farmed aquaculture species can counterintuitively lead to lowered harvestable biomass. We outbred a domesticated aquaculture stock of Chinook salmon (Oncorhynchus tshawytscha (Walbaum in Artedi, 1792)) with seven wild stocks from British Columbia, Canada. We then examined how functionally related traits underlying energy management – diel variation in cortisol and foraging, social, and movement behaviours — predicted stock-level variation in growth during the freshwater life history stage, which is a performance metric under aquaculture selection. Outbreeding generated significant variation in diel cortisol secretion and behaviours across stocks, and these traits co-varied, suggesting tight integration despite hybridization. The coupling of nighttime cortisol exposure with the daytime behavioural phenotype was the strongest predictor of stock-level variation in body mass. Our results suggest that selection for an integrated phenotype rather than on a single mechanistic trait alone can generate the greatest effect on aquaculture fish growth under outbreeding practices. Furthermore, selecting for these traits at the stock level may increase efficiency of farming methods designed to consistently maximize fish performance on a large scale.

Temporal variation in synchrony among chinook salmon (Oncorhynchus tshawytscha) redd counts from a wilderness area in central Idaho

2003 ◽  
Vol 60 (7) ◽  
pp. 840-848 ◽  
Author(s):  
Daniel J Isaak ◽  
Russell F Thurow ◽  
Bruce E Rieman ◽  
Jason B Dunham
Keyword(s):  
Chinook Salmon ◽  
Large Scale ◽  
Oncorhynchus Tshawytscha ◽  
Structured Populations ◽  
Strongly Correlated ◽  
Wilderness Area ◽  
Large Scale Disturbance ◽  
Stochastic Events ◽  
Central Idaho

Metapopulation dynamics have emerged as a key consideration in conservation planning for salmonid fishes. Implicit to many models of spatially structured populations is a degree of synchrony, or correlation, among populations. We used a spatially and temporally extensive database of chinook salmon (Oncorhynchus tshawytscha) redd counts from a wilderness area in central Idaho to examine patterns in synchrony as these fish underwent a sixfold decrease in abundance. Our results suggested that populations became strongly synchronous as abundances decreased and that the range, or diversity of correlations, exhibited among populations also decreased. These changes indicate that the likelihood of simultaneous extirpations has increased, which could have long-term detrimental consequences for metapopulation persistence. Implications for management are that the resilience of many metapopulations to large-scale disturbance and anthropogenic suppression may not depend solely on attempts to maintain large and productive component populations, but also on efforts to desynchronize populations that have become strongly correlated. Such efforts could entail promoting the existence of a broad distribution and diversity of habitats that support a wide array of life-history forms and ensuring that some habitats are sufficiently spatially disjunct so that risks from catastrophic stochastic events are minimized.

In a warming river, natural-origin Chinook salmon spawn later but hatchery-origin conspecifics do not

2021 ◽  
Vol 78 (1) ◽  
pp. 68-77
Author(s):  
Catherine S. Austin ◽  
Timothy E. Essington ◽  
Thomas P. Quinn
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
River System ◽  
Local Environment ◽  
Washington State ◽  
Human Intervention ◽  
Timing Of Reproduction ◽  
Natural Origin ◽  
Skagit River

Median timing of reproduction in salmonid populations is generally consistent among years, reflecting long-term patterns of natural selection from characteristics of the local environment. However, altered selection from factors related to climate change or human intervention might shift timing over generations, with implications for the population’s persistence. To study these processes, we modeled median timing of redd (nest) counts as an index of spawning timing by natural-origin Chinook salmon (Oncorhynchus tshawytscha) in the Skagit River system in Washington State, USA. Over the last 2–6 decades, natural-origin salmon have been spawning later by 0.03–0.52 days·year–1, while a naturally spawning group that is influenced by strays from a hatchery has been spawning earlier by 0.19 days·year–1. Trends in the spawning timing of hatchery-origin strays may reflect opposing selection from the hatchery, where egg take for propagation has become earlier by 0.58 days·year–1. As mean August river temperatures have risen over the period of record, hatchery timing trends may be moving in the opposite direction from the plastic or adaptive patterns expressed by natural-origin fish.

Analysis of microsatellite DNA resolves genetic structure and diversity of chinook salmon (Oncorhynchus tshawytscha) in California’s Central Valley

2000 ◽  
Vol 57 (5) ◽  
pp. 915-927 ◽  
Author(s):  
Michael A Banks ◽  
Vanessa K Rashbrook ◽  
Marco J Calavetta ◽  
Cheryl A Dean ◽  
Dennis Hedgecock
Keyword(s):  
Genetic Structure ◽  
Chinook Salmon ◽  
Microsatellite Dna ◽  
Life Histories ◽  
Oncorhynchus Tshawytscha ◽  
Random Mating ◽  
Central Valley ◽  
Microsatellite Dna Markers ◽  
Maximum Likelihood Methods ◽  
Genetic Structure And Diversity

We use 10 microsatellite DNA markers to assess genetic diversity within and among the four runs (winter, spring, fall, and late fall) of chinook salmon (Oncorhynchus tshawytscha) in California's Central Valley. Forty-one population samples are studied, comprising naturally spawning and hatchery stocks collected from 1991 through 1997. Maximum likelihood methods are used to correct for kinship in juvenile samples and run admixture in adult samples. Through simulation, we determine the relationship between sample size and number of alleles observed at polymorphic microsatellite markers. Most samples have random-mating equilibrium proportions of single and multilocus genotypes. Temporal and spatial genetic heterogeneity is minimal among samples within subpopulations. An FST of 0.082 among subpopulations, however, indicates substantial divergence among runs. Thus, with the exception of our discovery of two distinct lineages of spring run, genetic structure accords with the diverse chinook life histories seen in the Central Valley and provides a means for discrimination of protected populations.

scholarly journals Evaluation of Long-Term Mark-Recapture Data for Estimating Abundance of Juvenile Fall-Run Chinook Salmon on the Stanislaus River from 1996 to 2017

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Tyler Pilger ◽  
Matthew Peterson ◽  
Dana Lee ◽  
Andrea Fuller ◽  
Doug Demko
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Estimation Method ◽  
Central Valley ◽  
Mark Recapture ◽  
Important Species ◽  
Trap Efficiency ◽  
Monitoring Programs ◽  
Abundance Estimates

Conservation and management of culturally and economically important species rely on monitoring programs to provide accurate and robust estimates of population size. Rotary screw traps (RSTs) are often used to monitor populations of anadromous fish, including fall-run Chinook Salmon (Oncorhynchus tshawytscha) in California’s Central Valley. Abundance estimates from RST data depend on estimating a trap's efficiency via mark-recapture releases. Because efficiency estimates are highly variable and influenced by many factors, abundance estimates can be highly uncertain. An additional complication is the multiple accepted methods for how to apply a limited number of trap efficiency estimates, each from discrete time-periods, to a population’s downstream migration, which can span months. Yet, few studies have evaluated these different methods, particularly with long-term monitoring programs. We used 21 years of mark-recapture data and RST catch of juvenile fall-run Chinook Salmon on the Stanislaus River, California, to investigate factors associated with trap efficiency variability across years and mark-recapture releases. We compared annual abundance estimates across five methods that differed in treatment of trap efficiency (stratified versus modeled) and statistical approach (frequentist versus Bayesian) to assess the variability of estimates across methods, and to evaluate whether method affected trends in estimated abundance. Consistent with short-term studies, we observed negative associations between estimated trap efficiency and river discharge as well as fish size. Abundance estimates were robust across all methods, frequently having overlapping confidence intervals. Abundance trends, for the number of increases and decreases from year to year, did not differ across methods. Estimated juvenile abundances were significantly related to adult escapement counts, and the relationship did not depend on estimation method. Understanding the sources of uncertainty related to abundance estimates is necessary to ensure that high-quality estimates are used in life cycle and stock-recruitment modeling.

Changes in life history parameters in a naturally spawning population of chinook salmon (Oncorhynchus tshawytscha) associated with releases of hatchery-reared fish

1997 ◽  
Vol 54 (6) ◽  
pp. 1235-1245 ◽  
Author(s):  
M J Unwin ◽  
G J Glova
Keyword(s):  
Life History ◽  
New Zealand ◽  
Chinook Salmon ◽  
Life History Traits ◽  
Oncorhynchus Tshawytscha ◽  
Fork Length ◽  
Age At Maturity ◽  
Natural Origin ◽  
Parent Stock ◽  
Stream Type

Chinook salmon (Oncorhynchus tshawytscha) spawning runs in Glenariffe Stream, New Zealand, exhibited significant changes in life history traits following supplementation releases of hatchery-reared juveniles. Total run strength did not change but the proportion of naturally produced fish declined to 34%. Attempts to separate spawners of natural and hatchery origin were unsuccessful, and 31-48% of natural spawners are now of hatchery origin. Hatchery males were smaller at age 2 and 3 than males of natural origin, and more often matured as jacks, producing an 86-mm decrease in mean fork length over 28 years. There was no change in length at age or age at maturity for female spawners. The proportion of jacks entering Glenariffe Stream each year was positively correlated with the proportion of jacks in the ensuing cohort. Most differences between fish of natural and hatchery origin were related to hatchery rearing practices, but the decline in age at maturity among naturally produced males appears to reflect traits inherited from parent stock of hatchery origin. Hatchery releases may also favour the survival of ocean-type fry over stream-type fry, possibly reversing a tendency for stream-type behaviour to evolve in response to the lack of estuaries on most New Zealand chinook salmon rivers.

Dependence of Exploitation Rates for Maximum Yield and Stock Collapse on Age and Sex Structure of Chinook Salmon (Oncorhynchus tshawytscha) Stocks

1986 ◽  
Vol 43 (9) ◽  
pp. 1746-1759 ◽  
Author(s):  
David G. Hankin ◽  
M. C. Healey
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Maximum Yield ◽  
Complex Nature ◽  
Sex Structure ◽  
Early Maturing ◽  
Stock Recruitment ◽  
Mixed Stock ◽  
Age And Sex ◽  
Stock Collapse

In this paper we investigate the equilibrium behavior of an age- and sex-structured version of the Ricker stock–recruitment model specifically tailored to the complex nature of chinook salmon (Oncorhynchus tshawytscha) biology and fisheries. Conclusions from our analysis include the following. (1) Exploitation rates for maximum yield (umsy) and stock collapse (umax) depend strongly on a stock's maturity schedule, being lowest for a late-maturing stock and greatest for an early maturing stock. (2) Values of exploitation rates for umax overlap considerably with those for umsy, emphasizing the probability of stock collapse in fully exploited mixed stock fisheries. (3) Values of umsy and umax are independent of the value of the Ricker β parameter but depend directly on the Ricker α parameter, indicating that management research should focus on obtaining better estimates of α, contrary to recent suggestions in the literature. (4) Because they mature at older ages, female chinook suffer greater cumulative fishery removal rates than males and decline in abundance more rapidly as exploitation increases. Consequently, the use of sex-independent maturity schedules can give misleading estimates for umsy and umax. (5) Maximum changes in mean age of stocks that can be attributed to fishing up effects ranged from 0.32 to 0.81 yr. Many stocks appear already to have declined in mean age by this amount, further emphasizing the probability of impending collapse of some stocks.

Homing and Straying Patterns of Chinook Salmon (Oncorhynchus tshawytscha) from a New Zealand Hatchery: Spatial Distribution of Strays and Effects of Release Date

1993 ◽  
Vol 50 (6) ◽  
pp. 1168-1175 ◽  
Author(s):  
Martin J. Unwin ◽  
Thomas P. Quinn
Keyword(s):  
Spatial Distribution ◽  
New Zealand ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Complex Interaction ◽  
Research Station ◽  
Age At Maturity ◽  
Release Date

Homing and straying patterns of fall chinook salmon (Oncorhynchus tshawytscha) released from the Glenariffe Salmon Research Station on the Rakaia River, New Zealand, are reported, based on coded-wire tag recoveries from the 1978–84 brood years. Of 17 671 tagged adults recovered, 87.9% returned to the Rakaia, and the rest were recovered from 12 other catchments up to 500 km away. The number of strays entering a given river increased with discharge and with proximity to the Rakaia, but most strays were recorded in catchments north of the Rakaia. A higher proportion of salmon released in winter, when the downriver migration of naturally produced chinook is a minimum, strayed to other catchments (14.9–20.6%) than did those released at other times of the year (3.6–7.6%). However, straying within the Rakaia catchment was largely unaffected by release date, suggesting that imprinting by fry to the natal tributary is separate from imprinting by smolts to the mainstem river. There was a complex interaction between age at maturity, release date, and straying rates; straying of 4-yr-old fish was more strongly influenced by release date than straying of younger fish. Notwithstanding this interaction, straying was more prevalent among older fish.

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