Growth of northeast arctic cod in relation to ambient temperature

In the present study temperature related changes in horizontal distribution are described and the influence of temperature on the growth of Northeast Arctic cod is interpreted. Data from acoustic-and bottom trawl surveys in the Barents Sea each February 1988-1995 has been used to relate mean length at age to the ambient winter temperature. Mean lengths at age increased with increasing temperature for ages greater than 2 years. Individual mean growth between age 1 and age 4 was significantly higher for yearclasses (cohorts) experiencing higher temperatures than for yearclasses inhabiting colder waters. Our use of estimates of ambient temperature in February instead of annual mean values probably introduces an underestimation of the temperature effect on growth. Increased abundance of young cod is associated with an extension of the distribution area towards east and north into colder water. Hence a growth temperature relation may wrongly be interpreted as a growth-density (abundance) dependency if ambient temperature is not included in the analysis