The consumption rate of northeast Arctic cod - A comparison of gastric evacuation models

Abstract

The consumption rates in fish are important but also often weak points in multispecies models. In the Barents Sea multispecies model (MULTSPEC), as in many other models, quantitative stomach content data are combined with gastric evacuation data or models to produce consumption rates of important prey species. To evaluate the evacuation model presently used for cod in the Barents Sea and the derived consumption rates, we have combined stomach data from 1984 with five other evacuation models for cod. The results are compared and judged against data on prey stock sizes, individual cod growth, daily rations and food conversion efficiency. The rations derived from the different models ranged from 0.5 to 1.2% of the BW daily on average for all agegroups of cod or from 2.1 to 4.4 times the biomass of the total cod stock annually. Food conversion efficiency varied between 6 and 59% for the different models and agegroups.