Physiological and hormonal differences among Atlantic salmon parr and smolts reared in the wild, and hatchery smolts

Aquaculture
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Abstract

Atlantic salmon which had been released as fry in tributaries of the Connecticut River (Northeastern USA) were captured during the migratory period (9 May to 6 June) 1 to 2 years later. Migrants (smolts) were captured above a dam on the main-stem; non-migrants (parr) were captured in two tributaries. Migrants were significantly larger than non-migrants (16.9 and 13.0 cm, respectively), but had a 20% lower condition factor. Relative to non-migrants, migrants had significantly higher gill Na+, K+-ATPase activity (5-fold), plasma glucose (1.8-fold), plasma thyroxine (8-fold), plasma cortisol (5-fold) and plasma growth hormone (100-fold). There were no significant differences in plasma [Na+], [K+] and [Ca2+] between migrants and non-migrants. Most of the differences seen between non-migrants and migrants were similar to those that occurred seasonally in a captive (hatchery) population of the same stock of Atlantic salmon. However, hatchery smolts had lower levels of plasma thyroxine and exhibited no significant change in plasma growth hormone from February to June. The large differences between migrants and non-migrants may be related to both the parr-smolt transformation and migration.

Publication type Article
Publication Subtype Journal Article
Title Physiological and hormonal differences among Atlantic salmon parr and smolts reared in the wild, and hatchery smolts
Series title Aquaculture
DOI 10.1016/0044-8486(94)90023-X
Volume 121
Issue 1-3
Year Published 1994
Language English
Publisher Elsevier
Contributing office(s) Leetown Science Center
Description 10 p.
First page 235
Last page 244
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