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A decrease in photoperiod shortly after first feeding influences the development of Atlantic salmon (Salmo salar)

Citation

Berrill, IK and Smart, A and Porter, MJR and Bromage, NR, A decrease in photoperiod shortly after first feeding influences the development of Atlantic salmon (Salmo salar), Aquaculture, 254, (1-4) pp. 625-636. ISSN 0044-8486 (2006) [Refereed Article]

DOI: doi:10.1016/j.aquaculture.2005.10.036

Abstract

Four groups of Atlantic salmon fry (n = 2000) were exposed to continuous light (LD24 : 0) from first feeding on 18th April 2001, after which they were exposed to either an 8 or 12 week period of short days (LD10 : 14) starting on either the 21st May or the 18th June. Each group was then returned to LD24 : 0 until the conclusion of the experiment the following March. In August 200 fish per treatment were individually PIT tagged. All groups were maintained under an ambient temperature regime. The highest levels of sexual maturation in 0+ male parr were recorded in the 12 week/May group (> 11% of the entire male and female population), with the lowest levels (< 1%) in the 12 week/June treatment and intermediate levels (> 6%) in the 8 week/May and 8 week/June groups (P < 0.05). Between mid August and late October mature parr were heavier than their immature counterparts, but subsequently both cohorts maintained similar sizes. Fish showing signs of silvering were found from mid October onwards. However, it was only in the 12 week/June group that silvered fish had a significantly reduced condition factor and an increased gill Na+, K+-ATPase activity, indicative of smoltification. At the conclusion of the experiment, fish showing signs of silvering were most prevalent (30%) in the 12 week/June group. It is concluded that the initiation of maturation can be influenced by an 8 or 12 week period of short days (LD10 : 14) applied from mid May or mid June in the first growing season. The duration and timing of a stimulatory short day photoperiod during early development may also influence whether a fish undergoes smoltification in the coming year or whether it delays the parr-smolt transformation for at least a further year. © 2005 Elsevier B.V. All rights reserved.

Item Details

Item Type:Refereed Article
Research Division:Agricultural and Veterinary Sciences
Research Group:Fisheries Sciences
Research Field:Aquaculture
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - Aquaculture
Objective Field:Fisheries - Aquaculture not elsewhere classified
Author:Porter, MJR (Dr Mark Porter)
ID Code:42026
Year Published:2006
Web of Science® Times Cited:6
Deposited By:TAFI - Aquaculture
Deposited On:2006-08-01
Last Modified:2011-09-20
Downloads:0

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