Effect of parental mate choice and semi-natural early rearing environment on the growth performance and seawater tolerance of Chinook salmon Oncorhynchus tshawytscha

Document Type

Article

Publication Date

2013

Publication Title

Journal of Fish Biology

Volume

82

Issue

2

First Page

618

Last Page

636

Abstract

To assess whether parental mate choice and early rearing in a semi-natural spawning channel may benefit the culture of Chinook salmon Oncorhynchus tshawytscha, 90day growth trials were conducted using hatchery O. tshawytscha (hatchery), mate choice O. tshawytscha (i.e. the offspring of parents allowed to choose their own mate) that spent 6months in a spawning channel prior to hatchery rearing (channel) and mate choice O. tshawytscha transferred to the hatchery as fertilized eggs (transfer). During the growth trials, all O. tshawytscha stocks were reared separately or in either mixed channel and hatchery or transfer and hatchery groups for comparison of performance to traditional practices. After 60days in fresh water, all O. tshawytscha were transferred to seawater for an additional 30days. Reared separately, all stocks grew c. 4 center dot 5 fold over 90days but specific growth rate (G) and food conversion efficiency were higher in fresh water than after seawater transfer on day 60. In contrast, hatchery O. tshawytscha from mixed hatchery and channel and hatchery and transfer growth trials had a larger mass and length gain than their counterparts on day 60, but reduced G in seawater. In general, plasma levels of growth hormone, insulin-like growth factor I and cortisol did not differ among any O. tshawytscha groups in either the separate or mixed growth trials. Despite some differences in gill Na+,K+-ATPase activity, all O. tshawytscha had a high degree of seawater tolerance and experienced virtually no perturbation in plasma chloride following seawater transfer. Overall, all O. tshawytscha exhibited similar growth and seawater performance under traditional hatchery conditions and any benefit derived from either parental mate choice or semi-natural early rearing environment was only observed in the presence of mutual competition with hatchery O. tshawytscha.

DOI

10.1111/jfb.12018

Comments

This is an accepted manuscript version of an article whose version of record was published in:Journal of Fish Biology: http://dx.doi.org/10.1111/jfb.12018

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