title: Factors contributing to inter- and intra-annual variation in condition of cod Gadus morhua in the Barents Sea.
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.
authors.affiliation: University of Aberdeen, School of Biological Sciences, Zoology Building, Tillydrone Avenue, Aberdeen AB24 2TZ, Scotland, UK. l.sandeman@abdn.ac.uk
authors.forename: L R
authors.initials: LR
authors.lastname: Sandeman
authors.forename: N A
authors.initials: NA
authors.lastname: Yaragina
authors.forename: C T
authors.initials: CT
authors.lastname: Marshall
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D002980:Climate; D003710:Demography; D017753:Ecosystem; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D020387:Food Chain; D005523:Food Supply; D048389:Gadus morhua / Q000254:growth & development / Q000502:physiology*; D008297:Male; D009792:Oceans and Seas; D011157:Population Dynamics; D011158:Population Growth