Countergradient variation in growth and food conversion efficiency of juvenile turbot

• Published in: Journal of Fish Biology
• Main Authors: Imsland, A. K., Foss, A., Névdal, G., Cross, T., Bonga, S. W., Ham, E. A., Stefansson, S. O.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2000
• Subjects: Norway; Scophthalmus maximus; Turbot
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.2000.tb00482.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.2000.tb00482.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.2000.tb00482.x

Growth performance of a high latitude (Norway) population of juvenile turbot Scophthalmus maximus , was superior to that of two other lower latitude populations (Scotland, France) especially at 18° and 22° C. Overall these results lend some support to the hypothesis of countergradient variation in growth. The Norwegian population had the highest estimated temperature optimum for growth ( T opt.G , ±S.E.) (23·0±0·9°C) and food conversion efficiency ( T opt.Ec ) (17·5±0·3), followed by the French ( T opt.G 21·1±1·0; T opt.Ec , 16·7±0·1) population, whereas the Scottish population had the lowest optimum ( T opt.G , 19·6±0·6; T opt Ec , 16·5±0·1°C). These results have two major implications: firstly, for turbot culture, particularly in selection work focusing on growth performance; secondly, if countergradient variation in growth performance takes place within a species one cannot assume automatically that one set of physiological parameters, in this case growth‐related parameters, is satisfactory to predict growth for a species throughout its range as different populations might show a difference in response towards different physiological parameters.