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Physiological and endocrine changes in Atlantic salmon smolts during hatchery rearing, downstream migration and ocean entry

Canadian Journal of Fisheries and Aquatic Sciences

By:
, , , , , ,
DOI: 10.1139/cjfas-2012-0151

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Abstract

Billions of hatchery salmon smolts are released annually in an attempt to mitigate anthropogenic impacts on freshwater habitats, often with limited success. Mortality of wild and hatchery fish is high during downstream and early ocean migration. To understand changes that occur during migration, we examined physiological and endocrine changes in Atlantic salmon (Salmo salar) smolts during hatchery rearing, downstream migration, and early ocean entry in two successive years. Gill Na+/K+-ATPase activity increased in the hatchery during spring, increased further after river release, and was slightly lower after recapture in the ocean. Plasma growth hormone levels increased in the hatchery, were higher in the river, and increased further in the ocean. Plasma IGF-I remained relatively constant in the hatchery, increased in the river, then decreased in the ocean. Plasma thyroid hormones were variable in the hatchery, but increased in both river- and ocean-captured smolts. Naturally reared fish had lower condition factor, gill NKA activity, and plasma thyroxine than hatchery fish in the river but were similar in the ocean. This novel data set provides a vital first step in understanding the role and norms of endocrine function in smolts and the metrics of successful marine entry.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Physiological and endocrine changes in Atlantic salmon smolts during hatchery rearing, downstream migration and ocean entry
Series title:
Canadian Journal of Fisheries and Aquatic Sciences
DOI:
10.1139/cjfas-2012-0151
Volume
70
Issue:
1
Year Published:
2013
Language:
English
Publisher:
NRC Research Press
Contributing office(s):
Leetown Science Center
Description:
14 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Canadian Journal of Fisheries and Aquatic Sciences
First page:
105
Last page:
118
Country:
United States
State:
Maine