Relationship between smolt gill Na+, K+ ATPase activity and migration timing to avian predation risk of steelhead trout (Oncorhynchus mykiss) in a large estuary

We examined avian predation risk of juvenile steelhead trout (Oncorhynchus mykiss) migrating through the Columbia River Estuary in relation to their osmoregulatory physiology, body length, rearing conditions (hatchery or wild), migration timing, and migration year. From 2003 to 2006, mean gill Na+, K+ ATPase activity of migrating wild steelhead was greater than hatchery steelhead. Hatchery steelhead were always longer than wild steelhead. Wild steelhead never had higher plasma [Na+] or osmolality levels than hatchery fish after seawater challenge trials conducted in 2004, 2005, and 2006. More passive integrated transponder (PIT) tags from hatchery fish (19%; 126 of 678 fish) were detected on East Sand Island among bird nesting colonies than PIT tags of wild fish (14%; 70 of 509 fish), presumably consumed by birds. As gill Na+, K+ ATPase activity and migration date within a year increased, the probability of an individual fish being eaten by an avian predator decreased. Length, rear type, and year were not related to predation risk. These results show that physiology and migration timing of juvenile steelhead play an important role in a migrants risk to avian predation within an estuary.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f06-061 ◽

2006 ◽

Vol 63 (7) ◽

pp. 1627-1638 ◽

Cited By ~ 28

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.

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Rearing in a distorted magnetic field disrupts the ‘map sense’ of juvenile steelhead trout

Biology Letters ◽

10.1098/rsbl.2014.0169 ◽

2014 ◽

Vol 10 (6) ◽

pp. 20140169 ◽

Cited By ~ 29

Author(s):

Nathan F. Putman ◽

Amanda M. Meinke ◽

David L. G. Noakes

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Oncorhynchus Mykiss ◽

Uniform Field ◽

Steelhead Trout ◽

Hatchery Fish ◽

Test Orientation ◽

Marine Survival

We used simulated magnetic displacements to test orientation preferences of juvenile steelhead trout ( Oncorhynchus mykiss ) exposed to magnetic fields existing at the northernmost and southernmost boundaries of their oceanic range. Fish reared in natural magnetic conditions distinguished between these two fields by orienting in opposite directions, with headings that would lead fish towards marine foraging grounds. However, fish reared in a spatially distorted magnetic field failed to distinguish between the experimental fields and were randomly oriented. The non-uniform field in which fish were reared is probably typical of fields that many hatchery fish encounter due to magnetic distortions associated with the infrastructure of aquaculture. Given that the reduced navigational abilities we observed could negatively influence marine survival, homing ability and hatchery efficiency, we recommend further study on the implications of rearing salmonids in unnatural magnetic fields.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2016-0175 ◽

2017 ◽

Vol 74 (2) ◽

pp. 273-283 ◽

Cited By ~ 9

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.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f2011-087 ◽

2011 ◽

Vol 68 (10) ◽

pp. 1827-1835 ◽

Cited By ~ 11

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.

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