Estimating Salmon Spawning Escapement Using Capture–Recapture Methods

1993 ◽  
Vol 50 (6) ◽  
pp. 1181-1197 ◽  
Author(s):  
Carl J. Schwarz ◽  
Richard E. Bailey ◽  
James R. Irvine ◽  
Frank C. Dalziel
Keyword(s):  
Maximum Likelihood ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Maximum Likelihood Estimators ◽  
Small River ◽  
Standard Errors ◽  
Capture Recapture ◽  
Simulation Results ◽  
Biased Estimators

We describe a method of estimating the spawning escapement of coho salmon (Oncorhynchus kisutch) from capture–recapture data. Traditional capture–recapture analyses do not directly provide estimates of escapements; however, we show how simple modifications to the Jolly–Seber method can estimate the total number of fish returning to a river including those that enter and die between sampling occasions. Spawning runs of Pacific salmon were simulated and their escapements estimated using capture–recapture. The performance of the maximum likelihood estimators (MLEs), the censored MLEs, the constrained MLEs, and less-biased estimators in estimating the run sizes and providing estimates of precision were evaluated. Simulation results indicated that constrained MLEs provided the most appropriate estimates of escapement and that standard errors be computed using the large-sample variance formulae evaluated at these estimates. These methods were used to estimate the escapements of coho salmon to a small river on Vancouver Island in 1989 and 1990.

Estimates of stream residence time and escapement based on capture-recapture data

2000 ◽  
Vol 57 (1) ◽  
pp. 241-246 ◽  
Author(s):  
Micheline Manske ◽  
Carl J Schwarz
Keyword(s):  
Residence Time ◽  
Coho Salmon ◽  
Area Under The Curve ◽  
Oncorhynchus Kisutch ◽  
Accurate Estimate ◽  
Small River ◽  
Entire Population ◽  
Residence Times ◽  
Capture Recapture ◽  
Curve Method

The area-under-the-curve method is a widely used method for estimating salmon escapement. The method depends on obtaining an accurate estimate of stream residence time, or stream life. This paper develops an estimator of stream residence time based on capture-recapture data. If the capture-recapture experiment is performed on the entire population, the escapement can also be estimated using the area-under-the-curve method. Simulations showed that the stream residence estimator and the area-under-the-curve estimator provide precise estimates of stream residence and escapement, respectively. These methods were used to estimate the stream residence times and escapements of coho salmon (Oncorhynchus kisutch) in a small river on Vancouver Island in 1989 and 1990.

scholarly journals Evidence for Freshwater Residualism in Coho Salmon, Oncorhynchus kisutch, From a Watershed on the North Coast of British Columbia

2017 ◽  
Vol 130 (4) ◽  
pp. 336 ◽  
Author(s):  
Eric A Parkinson ◽  
Chris J Perrin ◽  
Daniel Ramos-Espinoza ◽  
Eric B Taylor
Keyword(s):  
British Columbia ◽  
Fresh Water ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Water Levels ◽  
North Coast ◽  
The North ◽  
Seaward Migration ◽  
Mature Fish

The Coho Salmon, Oncorhynchus kisutch, is one of seven species of Pacific salmon and trout native to northeastern Pacific Ocean watersheds. The species is typically anadromous; adults reproduce in fresh water where juveniles reside for 1–2 years before seaward migration after which the majority of growth occurs in the ocean before maturation at 2–4 years old when adults return to fresh water to spawn. Here, we report maturation of Coho Salmon in two freshwater lakes on the north coast of British Columbia apparently without their being to sea. A total of 15 mature fish (11 males and four females) were collected in two lakes across two years. The mature fish were all at least 29 cm in total length and ranged in age from three to five years old. The occurrence of Coho Salmon that have matured in fresh water without first going to sea is exceedingly rare in their natural range, especially for females. Such mature Coho Salmon may represent residual and distinct breeding populations from those in adjacent streams. Alternatively, they may result from the ephemeral restriction in the opportunity to migrate seaward owing to low water levels in the spring when Coho Salmon typically migrate to sea after 1–2 years in fresh water. Regardless of their origin, the ability to mature in fresh water without seaward migration may represent important adaptive life history plasticity in response to variable environments.

A preliminary study of insulin participation in the growth regulation of coho salmon (Oncorhynchus kisutch)

1977 ◽  
Vol 55 (10) ◽  
pp. 1756-1758 ◽  
Author(s):  
Bryan Ludwig ◽  
David A. Higgs ◽  
Ulf H. M. Fagerlund ◽  
Jack R. McBride
Keyword(s):  
Body Weight ◽  
Growth Regulation ◽  
Specific Growth ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Growth Promoter ◽  
Pancreatic B Cells ◽  
Preliminary Study ◽  
Specific Growth Rates

As part of an ongoing survey to identify hormones capable of stimulating growth in Pacific salmon, groups of underyearling coho salmon were injected with bovine (Ultralente) insulin (0.32, 1.0, 3.2, or 10 IU/kg body weight) into the peritoneal cavity either once or twice weekly for 70 days.All doses of insulin, when injected twice weekly, increased the values for specific growth rates and decreased those for food–gain ratios relative to solvent-injected controls, but the differences were not statistically significant. All doses of insulin caused a marked increase in the granulation of the pancreatic B cells. Plasma glucose concentrations in starved coho injected with 10 IU insulin/kg body weight were significantly lower than in solvent-injected controls 4 h after injection.It is concluded that proper evaluation of the effectiveness of insulin as a growth promoter for salmon requires further studies preferably using insulin preparations specific to teleosts.

Fecundity of Coho Salmon (Oncorhynchus kisutch) from the Great Lakes and a Comparison with Ocean Salmon

1976 ◽  
Vol 33 (5) ◽  
pp. 1150-1155 ◽  
Author(s):  
Thomas M. Stauffer
Keyword(s):  
Great Lakes ◽  
Early Life ◽  
First Generation ◽  
Lake Michigan ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Lake Superior ◽  
Oncorhynchus Kisutch ◽  
Early Life History ◽  
Freshwater Salmon

I measured fecundity of coho salmon (Oncorhynchus kisutch) that matured in the Great Lakes to make comparisons with Pacific Ocean coho salmon and among groups of Great Lakes salmon. Numbers of eggs produced (1600–3500) by Great Lakes salmon were comparable to production (1500–3300) by Pacific salmon of similar size. Average egg diameters of Lake Michigan (7.1–7.4 mm) and Pacific salmon (6.1–7.4 mm) were also comparable but Lake Superior eggs were smaller (5.1–5.4 mm). Fecundity of second generation freshwater salmon which originated from Lake Michigan eggs was similar to that of the first generation which originated from Pacific eggs because the average numbers (2938–3243) and diameters (7.1–7.4 mm) of eggs produced were about the same. On the average, Lake Michigan salmon contained more (2938) and larger (7.1-mm diam) eggs than did Lake Superior salmon (2150 and 5.1-mm diam) of the same year-class and early life history.

Metrics and sampling designs for detecting trends in the distribution of spawning Pacific salmon (Oncorhynchus spp.)

2012 ◽  
Vol 69 (4) ◽  
pp. 681-694 ◽  
Author(s):  
Stephanie J. Peacock ◽  
Carrie A. Holt
Keyword(s):  
Population Dynamics ◽  
Environmental Variability ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Sensitivity Analyses ◽  
Observation Error ◽  
Simulated Population ◽  
Age At Maturity ◽  
Status Assessment

The distribution of individuals among populations and in space may contribute to their resilience under environmental variability. Changes in distribution may indicate the loss of genetically distinct subpopulations, the deterioration of habitat capacity, or both. The distribution of Pacific salmon ( Oncorhynchus  spp.) among spawning locations has recently been recognized as an important component of status assessment by USA and Canadian management agencies, but metrics of spawning distribution have not been rigorously evaluated. We evaluated three metrics of spawning distribution and four sampling designs for their ability to detect simulated contractions in the production of coho salmon ( Oncorhynchus kisutch ). We simulated population dynamics at 100 sites using a spawner–recruit model that incorporated natural variability in recruitment, age-at-maturity, dispersal, and measurement error in observations of abundance. Sensitivity analyses revealed that high observation error and straying of spawners from their natal streams may mask changes in distribution. Furthermore, monitoring only sites with high spawner abundance, as is often practiced, failed to capture the simulated contraction of production, emphasizing the importance of matching monitoring programs with assessment objectives.

Two generations of outbreeding in coho salmon (Oncorhynchus kisutch): effects on size and growth

2005 ◽  
Vol 62 (11) ◽  
pp. 2538-2547 ◽  
Author(s):  
Erin K McClelland ◽  
James M Myers ◽  
Jeffrey J Hard ◽  
Linda K Park ◽  
Kerry A Naish
Keyword(s):  
Growth Rates ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Late Summer ◽  
Early Life History ◽  
Lower Growth ◽  
Freshwater Aquaculture ◽  
In Captivity ◽  
Two Generations

Outbreeding is a potential genetic risk in Pacific salmon (Oncorhynchus spp.) when aquaculture practices introduce nonnative domesticated fish to wild environments, making interbreeding with wild populations possible. In this study, F1 and F2 hybrid families of coho salmon (Oncorhynchus kisutch) were created using a captive freshwater aquaculture strain and a locally derived hatchery population that is integrated with naturally spawning fish. Intermediate growth was detected in F1 and F2 hybrids from crosses reared in captivity; both generations had mean weight and length values between those of the parent populations after their first year (p < 0.05). In the early life history stages, maternal effects increased alevin growth in progeny of hatchery dams relative to those of captive dams (p < 0.001). Aquaculture control families showed greater growth rates than hybrids in late summer of their 1st year and in the following spring (p < 0.05), while the hatchery controls had lower growth rates during the first summer (p < 0.05). Line cross analysis indicated that changes in additive and dominance interactions, but not unfavorable epistatic interactions, likely explain the differences in weight, length, and growth rate observed in hybrids of these stocks of coho salmon.

Selection for Adult Size in Female Coho Salmon (Oncorhynchus kisutch)

1986 ◽  
Vol 43 (10) ◽  
pp. 1946-1959 ◽  
Author(s):  
L B. Holtby ◽  
M. C. Healey
Keyword(s):  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Selective Advantage ◽  
Evolutionary Stable Strategy ◽  
Relative Fitness ◽  
Female Size ◽  
Adult Size ◽  
Stable Strategy ◽  
Wide Range

Several recent studies have presented evidence that large size confers a selective advantage to female Pacific salmon. Nevertheless, a wide range of female sizes is normally present in any spawning population. Two possible explanations exist for the observed range in female size. First, average female size might be determined by an optimizing process with variation around the optimum size due to individual differences in success at obtaining food. Second, various sizes of females might coexist as a mixed evolutionary stable strategy. Under the first explanation, females of sizes other than the optimum would display lower fitness whereas, under the second explanation, females of all sizes would be equally fit. We investigated factors affecting survival of eggs, fry, and smolts of coho salmon (Oncorhynchus kisutch) in Carnation Creek on Vancouver Island with a view to determining the relative fitness of different sized females. Egg-to-fry mortality was best explained by a model that included only the effects of stream bed scour and gravel quality. Including an effect of female size, expressed through depth of egg burying, worsened the model's predictive capability. We could find no evidence that the eggs of large females consistently survived better during incubation than those of small females. In fact, we observed three instances in which it appeared that the eggs of small females survived better. In Carnation Creek, large 1- and 2-yr-old smolts did not consistently survive better in the marine environment than small smolts. Thus, we were unable to demonstrate that the reproductive success of large females was consistently higher than that of small females, contrary to the hypothesis that female size is the result of an optimizing process. In Carnation Creek the observed range of female sizes probably represents an evolutionary stable strategy in which all sizes have equal fitness. We propose a model that predicts female size and variance in size based on the conflicting selective effects of gravel quality, scour, and competition for nest sites.

Movements of adult coho salmon (Oncorhynchus kisutch) during colonization of newly accessible habitat

2007 ◽  
Vol 64 (8) ◽  
pp. 1143-1154 ◽  
Author(s):  
Joseph H Anderson ◽  
Thomas P Quinn
Keyword(s):  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Conservation Strategy ◽  
Breeding Behavior ◽  
Spawning Site ◽  
Radio Transmitters ◽  
Accessible Habitat ◽  
Initial Process ◽  
Spawning Sites

Pacific salmon (Oncorhynchus spp.) have repeatedly exploited new habitat following glacial recession and some artificial introductions, yet the initial process of colonization is poorly understood. Landsburg Diversion Dam on the Cedar River, Washington, excluded salmon from 33 km of habitat for over a century until it was modified to allow passage in 2003. Adult coho salmon (Oncorhynchus kisutch) were sampled as they entered the newly accessible habitat in the first 3 years and a subset received radio transmitters to assess spawning site selection and movement. Annual counts of coho colonists increased over time, and in 2 of 3 years, daily dam passage was positively correlated with river discharge. Contrary to our prediction that coho would spawn in tributaries, all identified spawning sites were in the mainstem Cedar River, though 38% of radio-tagged salmon entered a tributary at least temporarily. Females moved little within the new habitat (average = 5.8 km), whereas males moved extensively (average = 34.8 km), especially when females were scarce. The immediate use of the new habitat by colonists and their widespread movements suggest that exploration is an innate component of salmon breeding behavior, and restoring access to lost habitat merits prioritization as a conservation strategy.

scholarly journals Scalable Bias-corrected Linkage Disequilibrium Estimation Under Genotype Uncertainty

2021 ◽  
Author(s):  
David Gerard
Keyword(s):  
Linkage Disequilibrium ◽  
Maximum Likelihood ◽  
Maximum Likelihood Estimation ◽  
Maximum Likelihood Estimators ◽  
Likelihood Estimation ◽  
Real Data ◽  
Standard Errors ◽  
Posterior Distributions ◽  
Posterior Mean ◽  
Genome Wide

AbstractLinkage disequilibrium (LD) estimates are often calculated genome-wide for use in many tasks, such as SNP pruning and LD decay estimation. However, in the presence of genotype uncertainty, naive approaches to calculating LD have extreme attenuation biases, incorrectly suggesting that SNPs are less dependent than in reality. These biases are particularly strong in polyploid organisms, which often exhibit greater levels of genotype uncertainty than diploids. A principled approach using maximum likelihood estimation with genotype likelihoods can reduce this bias, but is prohibitively slow for genome-wide applications. Here, we present scalable moment-based adjustments to LD estimates based on the marginal posterior distributions of the genotypes. We demonstrate, on both simulated and real data, that these moment-based estimators are as accurate as maximum likelihood estimators, and are almost as fast as naive approaches based only on posterior mean genotypes. This opens up bias-corrected LD estimation to genome-wide applications. Additionally, we provide standard errors for these moment-based estimators. All methods are implemented in the ldsep package on the Comprehensive R Archive Network https://cran.r-project.org/package=ldsep.

Precocious Induction of Oocyte Maturation and Ovulation in Coho Salmon, Oncorhynchus kisutch

1978 ◽  
Vol 35 (11) ◽  
pp. 1423-1429 ◽  
Author(s):  
Bernard Jalabert ◽  
Frederick W. Goetz ◽  
Bernard Breton ◽  
Alexis Fostier ◽  
Edward M. Donaldson
Keyword(s):  
Key Words ◽  
Oocyte Maturation ◽  
Negative Feedback ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Induced Ovulation ◽  
Final Oocyte Maturation ◽  
Final Maturation

Coho salmon (Oncorhynchus kisutch) were induced to ovulate 3–5 wk ahead of the normal time using partially purified salmon gonadotropin (SG-G100) alone or in combination with 17αhydroxy 20β dihydroprogesterone (17α-20βP). Treatment with 17α-20βP alone induced final oocyte maturation but not ovulation and was associated with a negative feedback upon endogenous gonadotropin. The most successful treatments consisted of a "priming" injection of 0.1 mg/kg SG-G100 followed within 2–3 d by an injection of either 1 mg/kg SG-G100 or 3 mg/kg 17α-20βP. Ova from the ovulated fish were successfully fertilized. This is the first occasion in which the time of spawning has been controlled in adult migrant Pacific salmon. Key words: coho salmon, Oncorhynchus kisutch, induced ovulation, final maturation, SG-G100, gonadotropin, 17α-20β dihydroprogesterone

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