The effects of adult length and arrival date on individual reproductive success in wild steelhead trout (Oncorhynchus mykiss)

2004 ◽  
Vol 61 (2) ◽  
pp. 193-204 ◽  
Author(s):  
Todd R Seamons ◽  
Paul Bentzen ◽  
Thomas P Quinn
Keyword(s):  
Reproductive Success ◽  
Oncorhynchus Mykiss ◽  
General Trend ◽  
Offspring Size ◽  
Natural Setting ◽  
Adult Size ◽  
Steelhead Trout ◽  
Arrival Date ◽  
Affected Offspring ◽  
Genetically Determined

To determine the relative importance of adult size and arrival date for reproductive success in a natural setting, we first genetically determined relationships between all spawning adult steelhead (Oncorhynchus mykiss) and juvenile offspring in four brood years and then tested hypothesized relationships between parents' phenotypes and the number and size of their juvenile offspring. Patterns of reproductive success varied among years, but in all cases, a few adults of each sex produced most of the offspring. The number of offspring showed a weak, positive relationship to the mother's size but not to her arrival date. Paternal reproductive success varied considerably but was only weakly associated with size in 1998 and weakly related to arrival date in 2000. In 1997, 1998, and 1999, the offspring of early-spawning females were larger at the end of their first and second summers in the stream; however, in 2000, both arrival date and length were positively related to offspring size. There was no general trend in offspring size in relation to paternal size or arrival date; however, paternal length affected offspring size in 1998 and male arrival date affected offspring size in 2000.

Bias and significance of relative reproductive success estimates based on steelhead trout (Oncorhynchus mykiss) data: a Bayesian meta-analysis

2011 ◽  
Vol 68 (10) ◽  
pp. 1827-1835 ◽  
Author(s):  
Shuichi Kitada ◽  
Hirohisa Kishino ◽  
Katsuyuki Hamasaki
Keyword(s):  
Reproductive Success ◽  
Oncorhynchus Mykiss ◽  
Meta Analysis ◽  
Wild Fish ◽  
Steelhead Trout ◽  
Bayesian Hierarchical ◽  
Hatchery Fish ◽  
In The Wild ◽  
The Mean ◽  
Log Normal

The evaluation of the reproductive success (RS) of hatchery fish in the wild is one of the most important issues in hatchery supplementation, aquaculture, and conservation. Estimates of the relative reproductive success (RRS) have been used to evaluate RS. Because RRS may vary greatly depending on cross, years of release, and environmental conditions, we introduced a log-normal distribution to quantify the variation. The classical estimator of RRS based on multiple measurements is contrasted with the mean of this distribution. We derived the mean, variance, and relative bias and applied our Bayesian hierarchical model to 42 empirical RRS estimates of steelhead trout ( Oncorhynchus mykiss ) in the Hood River, Oregon, USA. The RRS estimate generally had an upward bias. Although the average level of RRS implied the reproductive decline of hatchery fish and wild-born hatchery descendants, we could not reject the null hypothesis that hatchery fish and their descendants have the same chance of having smaller RS than wild fish as they do of having larger RS than wild fish.

Differential reproductive success of sympatric, naturally spawning hatchery and wild steelhead trout (Oncorhynchus mykiss) through the adult stage

2003 ◽  
Vol 60 (4) ◽  
pp. 433-440 ◽  
Author(s):  
Jennifer E McLean ◽  
Paul Bentzen ◽  
Thomas P Quinn
Keyword(s):  
Reproductive Success ◽  
Oncorhynchus Mykiss ◽  
Adult Stage ◽  
Poor Performance ◽  
Adult Offspring ◽  
Steelhead Trout ◽  
Freshwater Environment ◽  
Domestication Selection ◽  
In The Wild ◽  
Differential Reproductive Success

We used multilocus microsatellite analysis to compare the reproductive success of naturally spawning wild steelhead trout (Oncorhynchus mykiss) with a newly established sympatric hatchery population in Forks Creek, Washington, U.S.A. Hatchery steelhead spawning in the wild had markedly lower reproductive success than native wild steelhead. Wild females that spawned in 1996 produced 9 times as many adult offspring per capita as did hatchery females that spawned in the wild. Wild females that spawned in 1997 produced 42 times as many adult offspring as hatchery females. The wild steelhead population more than met replacement requirements (approximately 3.7–6.7 adult offspring were produced per female), but the hatchery steelhead were far below replacement requirements (<0.5 adults per female). The survival differential was greatest in the freshwater environment (i.e., production of seaward-migrating juveniles), but survival at sea favored the hatchery population in 1 year and the wild population in the next. The poor performance of the hatchery population may be a consequence of spawning too early in the winter, generations of inadvertent domestication selection, or a combination of these two.

Riverine characteristics and adult demography influence female lake sturgeon (Acipenser fulvescens) spawning behavior, reproductive success, and ovarian quality

2019 ◽  
Vol 76 (7) ◽  
pp. 1147-1160 ◽  
Author(s):  
Kari J. Dammerman ◽  
Molly A.H. Webb ◽  
Kim T. Scribner
Keyword(s):  
Reproductive Success ◽  
Behavioral Plasticity ◽  
Lake Sturgeon ◽  
Operational Sex Ratio ◽  
Plasma Testosterone ◽  
Acipenser Fulvescens ◽  
Reproductive Costs ◽  
Arrival Date ◽  
Factors Influencing ◽  
Yearly Means

Abiotic conditions and demographic factors can influence the timing of spawning. Behavioral plasticity allows females to select spawning conditions that are conducive to offspring development; however, reproductive costs associated with delaying spawning are not well understood. In this study, factors influencing timing of female spawning, residence time (RT), and reproductive success (RS) during two seasons were determined, and plasma testosterone concentrations were used to quantify atretic rates in a wild, lake sturgeon (Acipenser fulvescens) population. For the 123 females monitored, RT ranged from 1 to 23 days and was influenced by arrival date, temperature, discharge, and male number, with the latter having the largest influence. RS varied due to arrival date, temperature, discharge, male number, male length, and operational sex ratio. Two females had testosterone levels indicative of atresia and RS estimates lower than yearly means; however, most females had normal ovaries, suggesting little reproductive costs of plasticity in spawning ground residency time. Results demonstrate the multitude of factors influencing female reproductive behavior and RS, highlighting the importance of abiotic and demographic conditions to recruitment in wild populations.

scholarly journals Reproductive Success of American Kestrels: The Role of Prey Abundance and Weather

The Condor ◽  
2000 ◽  
Vol 102 (4) ◽  
pp. 814-822 ◽  
Author(s):  
Russell D. Dawson ◽  
Gary R. Bortolotti
Keyword(s):  
Reproductive Success ◽  
Natural Variation ◽  
Weather Conditions ◽  
Prey Abundance ◽  
Offspring Size ◽  
Minimum Threshold ◽  
Provisioning Behavior ◽  
American Kestrels ◽  
Parental Provisioning

Abstract We investigated how natural variation in abundance and availability of the main prey of American Kestrels (Falco sparverius), small mammals, influenced provisioning rates by parents, and offspring size and survival. Provisioning behavior of kestrels was not constrained by the abundance of food in the environment; however, the availability of food, mediated through variation in weather, appeared to significantly influence parental provisioning behavior. Moreover, variation in weather had clear effects on reproductive success because nestlings exposed to inclement weather were smaller and lighter at fledging, and less likely to survive to fledging, compared to nestlings raised during good weather conditions. Prey abundance was not related to offspring size or survival. Our results suggest American Kestrels are limited by the availability, as opposed to abundance, of food on territories. It is likely that during our study, prey abundance was above some minimum threshold necessary to support successful reproduction, and so variation in weather affected reproduction more than variation in prey abundance.

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