An analysis of over 10 000 cod stomachs from fish collected off the coast of Newfoundland and Labrador in Canada over several years and at different times of the year led to the conclusion that the consumption of prey by spawning cod of both sexes was equal to or greater than that of non-spawning cod.
There were, however, clear differences between the diet of the two groups: spawning cod consumed more lipid-rich prey (especially capelin), whilst non-spawning cod consumed more crab and sand lance. These differences could relate to spawning behaviour or physiological demand.
Regional differences were also evident: cod from more northerly locations fed more but on fewer types of prey (almost all shrimp), whereas cod from more southerly locations fed less but had a more diverse diet rich in pelagic fishes. These dietary contrasts likely contribute to well-known differences in both the growth and the condition of cod from these regions.
The observations reported through the investigation and in the paper provide important input to bioenergetic, migration, and ecosystem models in which cod are a component.
Kyle Krumsick and George Rose identifying a toad crab found in the stomach of a spawning Atlantic cod.