GEOGRAPHIC VARIATION IN GROWTH AND FOOD CONVERSION EFFICIENCY OF JUVENILE ATLANTIC HALIBUT RELATED TO LATITUDE

T.M. Jonassen,  A.K. Imsland,  R. Fitzgerald,  S.W. Bonga,  E.V. Ham,  G. Naevdal,  M.Ö. Stefánsson,  S.O. Stefansson-2000
Journal of Fish Biology, 56 (2): 279-294

Abstract:
Higher growth capacity and food conversion efficiency was observed in populations of juvenile halibut from high Hippoglossus hippoglossus compared lower latitudes. In addition, temperature adaptation shown by the lower temperature optimum for growth in the Norwegian population (mean +/- s.e. 12.9+/-0.1 C) compared with the Icelandic and Canadian populatins (14.2+/-0.2 and 13.9+/-0.3 C respectively), seems to occur. Overall the data support the hypothesis of countergradient variation in growth. These results have implications firstly for selection focusing on growth performance in halibut culture; and secondly, for safe prediction of growth, since if countergradient variation in growth performance occurs one cannot assume automatically that a species will respond to the same set of physiological parameters in the same way throughout its range. (Aquaculture Development Centre, Department of Zoology and Animal Ecology, National University of Ireland, Cork, Lee Maltings, Prospect Row, Cork, Ireland, tel.: +47 55 58 4471, fax: +47 55 58 4450, e-mail:albert.imsland@ifm.uib.no)

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