scholarly journals Offspring of first-generation hatchery steelhead trout (Oncorhynchus mykiss) grow faster in the hatchery than offspring of wild fish, but survive worse in the wild: Possible mechanisms for inadvertent domestication and fitness loss in hatchery salmon

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0257407
Author(s):  
Michael S. Blouin ◽  
Madeleine C. Wrey ◽  
Stephanie R. Bollmann ◽  
James C. Skaar ◽  
Ronald G. Twibell ◽  
...  
Keyword(s):  
Body Size ◽  
Oncorhynchus Mykiss ◽  
First Generation ◽  
Fat Content ◽  
Wild Fish ◽  
Steelhead Trout ◽  
Final Size ◽  
Lower Survival ◽  
Low Fat Diet ◽  
In The Wild

Salmonid fish raised in hatcheries often have lower fitness (number of returning adult offspring) than wild fish when both spawn in the wild. Body size at release from hatcheries is positively correlated with survival at sea. So one explanation for reduced fitness is that hatcheries inadvertently select for trait values that enhance growth rate under the unnatural environment of a hatchery, but that are maladaptive in the wild environment. A simple prediction of this hypothesis is that juveniles of hatchery origin should grow more quickly than fish of wild origin under hatchery conditions, but should have lower survival under wild conditions. We tested that hypothesis using multiple full sibling families of steelhead (Oncorhynchus mykiss) that were spawned using either two wild parents (WxW) or two first-generation hatchery (HxH) parents. Offspring from all the families were grown together under hatchery conditions and under semi-natural conditions in artificial streams. HxH families grew significantly faster in the hatchery, but had significantly lower survival in the streams. That we see this tradeoff after only a single generation of selection suggests that the traits involved are under very strong selection. We also considered one possible alteration to the hatchery environment that might reduce the intensity of selection among families in size at release. Here we tested whether reducing the fat content of hatchery feed would reduce the variance among families in body size. Although fish raised under a low-fat diet were slightly smaller, the variation among families in final size was unchanged. Thus, there is no evidence that reducing the fat content of hatchery feed would reduce the opportunity for selection among families on size at release.

scholarly journals Offspring of first-generation hatchery steelhead trout (Oncorhynchus mykiss) grow faster in the hatchery than offspring of wild fish, but survive worse in the wild: possible mechanisms for inadvertent domestication and fitness loss in hatchery salmon

2021 ◽  
Author(s):  
Michael Blouin ◽  
Madeleine C Wrey ◽  
Stephanie R Bollmann ◽  
James C Skaar ◽  
Ronald G Twibell ◽  
...  
Keyword(s):  
Body Size ◽  
Oncorhynchus Mykiss ◽  
First Generation ◽  
Fat Content ◽  
Wild Fish ◽  
Steelhead Trout ◽  
Final Size ◽  
Lower Survival ◽  
Low Fat Diet ◽  
In The Wild

Salmonid fish raised in hatcheries often have lower fitness (number of returning adult offspring) than wild fish when both spawn in the wild. Body size at release from hatcheries is positively correlated with survival at sea.  So one explanation for reduced fitness is that hatcheries inadvertently select for trait values that enhance growth rate under the unnatural environment of a hatchery, but that are maladaptive in the wild environment.  A simple prediction of this hypothesis is that juveniles of hatchery origin should grow more quickly than fish of wild origin under hatchery conditions, but should have lower survival under wild conditions.  We tested that hypothesis using multiple full sibling families of steelhead ( Oncorhynchus mykiss ) that were spawned using either two wild parents (WxW) or two first-generation hatchery (HxH) parents.  Offspring from all the families were grown together under hatchery conditions and under semi-natural conditions in artificial streams.  HxH families grew significantly faster in the hatchery, but had significantly lower survival in the streams.  That we see this tradeoff after only a single generation of selection suggests that the traits involved are under very strong selection.  We also considered one possible alteration to the hatchery environment that might reduce the intensity of selection among families in size at release. Here we tested whether reducing the fat content of hatchery feed would reduce the variance among families in body size. Although fish raised under a low-fat diet were slightly smaller, the variation among families in final size was unchanged.  Thus, there is no evidence that reducing the fat content of hatchery feed would reduce the opportunity for selection among families on size at release.

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.

Comparisons between hatchery and wild steelhead trout (Oncorhynchus mykiss) smolts: physiology and habitat use

2006 ◽  
Vol 63 (7) ◽  
pp. 1627-1638 ◽  
Author(s):  
Megan S Hill ◽  
Gayle Barbin Zydlewski ◽  
William L Gale
Keyword(s):  
Habitat Use ◽  
Atpase Activity ◽  
Oncorhynchus Mykiss ◽  
Plasma Osmolality ◽  
Wild Fish ◽  
Microhabitat Use ◽  
Steelhead Trout ◽  
Hatchery Fish ◽  
Before And After ◽  
Seawater Challenge

Hatchery steelhead trout (Oncorhynchus mykiss) smolts, progeny of a newly founded native origin broodstock, were released into Abernathy Creek, Washington, in 2003 and 2004. After release, saltwater tolerance, gill Na+,K+-ATPase activity, and habitat use were compared. A subsample of hatchery and wild steelhead trout were implanted with 23 mm passive integrated transponder (PIT) tags each year. PIT-tagged migrants were used for physiological comparisons. Hatchery fish were significantly larger than wild fish. Hatchery migrants expressed significantly lower levels of gill Na+,K+-ATPase activity than wild migrants. After a 24 h seawater challenge, hatchery migrants had significantly higher plasma osmolality and [Na+] than wild migrants. Microhabitat use of PIT-tagged hatchery and wild individuals in a control (wild fish only) and effect (hatchery and wild fish) site were compared before and after the introduction of hatchery fish. No difference was detected in hatchery and wild smolt habitat use. Wild fish did not change their habitat use after the introduction of hatchery fish. Although hatchery and wild fish differed in smolt physiology, differences in short-term use of freshwater habitat were not detected, and hatchery fish did not appear to displace wild fish.

scholarly journals Rearing strategies alter patterns of size-selective mortality and heritable size variation in steelhead trout (Oncorhynchus mykiss)

2017 ◽  
Vol 74 (2) ◽  
pp. 273-283 ◽  
Author(s):  
Barry A. Berejikian ◽  
Jeffrey J. Hard ◽  
Christopher P. Tatara ◽  
Donald M. Van Doornik ◽  
Penny Swanson ◽  
...  
Keyword(s):  
Body Size ◽  
Oncorhynchus Mykiss ◽  
Size Variation ◽  
Fork Length ◽  
Steelhead Trout ◽  
Selective Mortality ◽  
Food Ration ◽  
Family Effects ◽  
Growth Opportunity ◽  
Seawater Challenge

Steelhead trout (Oncorhynchus mykiss) reared under two different regimes: high food ration for 1 year (S1; typical strategy) or low ration for 2 years (S2) were subjected to a seawater challenge during the corresponding spring outmigration period. The S1 smolts were smaller and suffered greater seawater challenge mortality (23.9% compared with 0.7% for the S2 smolts) that was significantly and negatively related to body size. Heritability of body size was similar for the two treatments during the parr stage (fork length: S1 = 0.181, S2 = 0.245; mass: S1 = 0.372; S2 = 0.447), but higher for the S1 treatment during the smolt stage for length (S1 = 0.212, S2 = 0.002) and body mass (S1 = 0.145, S2 = 0.015). Strong family effects for both traits and significant family by environment interactions for parr mass and smolt length indicated significant phenotypic plasticity. A genetic response to size-selective mortality caused by insufficient growth opportunity in the S1 treatment is plausible and may affect fitness in the natural environment through effects on correlated traits.

Interbreeding with Domestic Strain Increases Foraging under Threat of Predation in Juvenile Steelhead Trout (Oncorhynchus mykiss): An Experimental Study

1991 ◽  
Vol 48 (2) ◽  
pp. 243-247 ◽  
Author(s):  
Jörgen I. Johnsson ◽  
Mark V. Abrahams
Keyword(s):  
Experimental Study ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Foraging Behaviour ◽  
Wild Population ◽  
Mortality Rates ◽  
Wild Fish ◽  
Risk Exposure ◽  
Steelhead Trout ◽  
Safe Area

The foraging behaviour of laboratory-reared juvenile steelhead trout (Oncorhynchus mykiss) and steelhead/domesticated rainbow trout hybrids were compared. In 10 replicate experiments, 10 fish from each strain were allowed to choose between foraging in a safe area or an area containing a predator. The hybrid trout were significantly more willing to risk exposure to the predator than were the steelhead. It was possible that differences in the relative willingness to risk exposure may have reflected differences in their susceptibility to predation. A second experiment measured the susceptibility of these two strains to the predator by simulating standardized encounters between predator and prey. Both strains suffered identical mortality rates and therefore were considered to be equally susceptible to the predator. This experiment confirmed that the hybrid trout were significantly more willing to take risks than the wild steelhead. These results indicate that interbreeding between escaped hatchery and wild fish may have a potentially damaging effect on the wild population.

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.

Food Abundance, Intruder Pressure, and Body Size as Determinants of Territory Size in Juvenile Steelhead Trout (Oncorhynchus Mykiss)

Behaviour ◽  
1998 ◽  
Vol 135 (1) ◽  
pp. 65-82 ◽  
Author(s):  
◽  
Keyword(s):  
British Columbia ◽  
Body Size ◽  
Atlantic Salmon ◽  
Oncorhynchus Mykiss ◽  
Food Abundance ◽  
Territory Size ◽  
Invertebrate Drift ◽  
Steelhead Trout ◽  
Daily Ration ◽  
Fish Size

AbstractWe observed the behaviour of juvenile steelhead trout (Oncorhynchus mykiss) in two rivers in British Columbia, Canada, to determine the importance of invertebrate drift abundance, intruder pressure, and body size of territory holders as correlates of territory size. Territory size increased with increasing fish size, but fish smaller than 5 cm had relatively large territories for their body size, in comparison to fish that were larger than 5 cm in length. After statistically controlling for the effect of body size, territory size was inversely related to the abundance of drifting invertebrates. Territory size was not related to the number of intrusions observed on a territory per hour, but was inversely related to local fish density, a second measure of intruder pressure. Steelhead trout appear to defend territory areas that are most similar in size to juvenile Atlantic salmon. This study provides evidence that stream-dwelling salmonids scale territory size to body size in a manner that allows them to capture a maximum daily ration of food on their territories.

Non-Fasting Factor VII Coagulant Activity (FVII:C) Increased by High-Fat Diet

1994 ◽  
Vol 71 (06) ◽  
pp. 755-758 ◽  
Author(s):  
E M Bladbjerg ◽  
P Marckmann ◽  
B Sandström ◽  
J Jespersen
Keyword(s):  
High Fat Diet ◽  
Fat Content ◽  
Factor Vii ◽  
Amidolytic Activity ◽  
High Fat ◽  
Low Fat Diet ◽  
Increased Risk ◽  
Coagulant Activity ◽  
High Fat Diets ◽  
Fat Diets

SummaryPreliminary observations have suggested that non-fasting factor VII coagulant activity (FVII:C) may be related to the dietary fat content. To confirm this, we performed a randomised cross-over study. Seventeen young volunteers were served 2 controlled isoenergetic diets differing in fat content (20% or 50% of energy). The 2 diets were served on 2 consecutive days. Blood samples were collected at 8.00 h, 16.30 h and 19.30 h, and analysed for triglycerides, FVII coagulant activity using human (FVII:C) or bovine thromboplastin (FVII:Bt), and FVII amidolytic activity (FVIPAm). The ratio FVII:Bt/FVII:Am (a measure of FVII activation) increased from fasting levels on both diets, but most markedly on the high-fat diet. In contrast, FVII: Am (a measure of FVII protein) tended to decrease from fasting levels on both diets. FVII:C rose from fasting levels on the high-fat diet, but not on the low-fat diet. The findings suggest that high-fat diets increase non-fasting FVII:C, and consequently may be associated with increased risk of thrombosis.

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