ABSTRACT
1. Relative body condition (the quantity of stored energy) is an important tool in understanding demographic variation and the ability of a population to respond to environmental stressors, varying food availability and competition. 2. A high-resolution database was used to examine causes of variation in the condition of north-east Arctic cod (Gadus morhua L.) for the period 1967-2004, over annual and monthly timescales. Community dynamics and climate variation were also tested as potential causes. 3. Temperature was shown to have a positive impact on condition at both inter- and intra-annual timescales. Inter-annually, temperature may affect stock distribution, in particular its overlap with the capelin stock. At shorter timescales it is likely that temperature directly affects the metabolism of the cod. 4. Intra-annually, the quantity of capelin in cod stomachs positively affected cod condition in the current and the preceding month for all lengths of cod. This indicated a time lag between a change in food consumption and a subsequent change in condition, or 'latency'. 5. Our study has shown that variation in temperature is a vital determinant of changes in condition, both at inter- and intra-annual timescales. Furthermore, the principle of latency has been demonstrated at the population level. Indirect effects of competition for energy-rich resources have been shown to have a negative effect on condition. This study supplements our knowledge of the implications for condition of changes in climate and in potential food resources.
