The effect of low temperatures and photoperiods on growth and vertebra morphometry in Atlantic salmon
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The aim of this study was to reveal possible interactive effects of temperature and photoperiod on somatic and skeletal growth, feed conversion, organ indexes and blood chemistry in Atlantic salmon postsmolts. A total of 1140 (initial mean weight 96.0 g ± 3.1 SEM) juvenile Atlantic salmon reared in seawater were in duplicates exposed to six different combinations of temperatures (4.3, 6.5 or 9.3 °C) and photoperiods (continuous light, LL or simulated natural photoperiod (69ºN), LDN) for 124 days. An interactive effect of photoperiod and temperature on somatic growth was found as the fish exposed to low temperature and continuous light regime (4LL) had a significantly higher growth (30 % gain in overall SGR) than the 4LDN group, corresponding to the effect of approx. 1.2 °C temperature increase. Fish in the 6 and 9 °C groups did not show any significant growth benefit of continuous light. Compared to the 4LDN group, the 4LL group showed higher total feed conversion efficiency, lower levels of blood Na+ and lower hepato-somatic and cardio-somatic indexes. In the skeleton, cervical vertebra were largest in the 4LL group, while the length of the head was largest in the 4LDN group, continuous light promotes growth at lower temperatures while supporting a normal development. It is suggested that a considerable growth benefit may be achieved by exposing juvenile Atlantic salmon to continuous light when reared at low (in this trial 4.3 °C) water temperature during winter.
KeywordsSalmon Temperature Photoperiod Growth Vertebra morphology
Analysis of variance
Simulated natural photoperiod
Specific growth rate
Financial support was given by the Research Council of Norway (RFFNord, Contract: 226059 NORDLYS).
- Aas Ø, Klemetsen A, Einum S, Skurdal J (2011) Atlantic salmon ecology. Wiley-Blackwell, West SussexGoogle Scholar
- Fjelldal PG, Hansen T, Breck O, Sandvik R, Waagbø R, Berg A, Ørnsrud R (2009) Supplementation of dietary minerals during the early seawater phase increase vertebral strength and reduce the prevalence of vertebral deformities in fast growing under-yearling Atlantic salmon (Salmo salar L.) smolt. Aquac Nutr 15:366–378CrossRefGoogle Scholar
- Houde ED, Schekter RC (1981) Growth rates, rations and cohort consumption of marine fish larvae in relation to prey concentrations. Rapp Proc-verb Réun Con inter l’Explor Mer 178:441–453Google Scholar
- Hovland E, Møller D (2010) Åkeren kan òg være blå. Et riss av havbruksnæringens utvikling i Norge (The field can also be blue. The history of aquaculture in Norway). Norwegian Directory of Fisheries, Bergen, Norway, ISBN 978-82-93011-06-4Google Scholar
- Kacem A, Meunier FJ, Bagliniere JL (1998) A quantitative study of morphological and histological changes in the skeleton of Salmo salar during its anadromous migration. J Fish Biol 53:1096–1109Google Scholar
- Pettersen JM, Bracke MBM, Midtlyng PJ, Folkedal O, Stien LH, Steffenak H, Kristiansen TS (2014) Salmon welfare index model 2.0: an extended model for overall welfare assessment of caged Atlantic salmon, based on a review of selected welfare indicators and intended for fish health professionals. Rev Aquac 6:162–179. doi:10.1111/raq.12039 CrossRefGoogle Scholar
- Roth B, Johansen SJS, Suontama J, Kiessling A, Leknes O, Guldberg B, Handeland S (2005) Seasonal variation in flesh quality, comparison between large and small Atlantic salmon (Salmo salar) transferred into seawater as 0+ or 1+ smolts. Aquaculture 250:830–840. doi:10.1016/j.aquaculture.2005.05.009 CrossRefGoogle Scholar
- Zar JH (1996) Biostatistical analysis, 3rd edn. Prentice-Hall, Englewood CliffsGoogle Scholar