Cannibalism and year-class strength in Atlantic cod (Gadus morhua L.) in Arcto-boreal ecosystems (Barents Sea, Iceland, and eastern Newfoundland)

Stomach content data collected from cod caught during offshore resource assessment surveys in three Arcto-boreal ecosystems were examined to determine the prevalence of cannibalism, and to identify possible factors associated with variability in prevalence.

Abstract

Stomach content data collected from cod caught during offshore resource assessment\nsurveys in three Arcto-boreal ecosystems (the Barents Sea and the shelves off Iceland\nand eastern Newfoundland) were examined to determine the prevalence of cannibalism,\nand to identify possible factors associated with variability in prevalence. Cannibalism\nprovides a minor source of food, except for the largest predators. Cannibalism\nIncreases with predator length. Most prey are less than 40 cm In length and less than 3\nyears old. In each region, cannibalism occurs over most of the area surveyed, but is\nmost prevalent where the smallest cod have been found in bottom trawl surveys. The\nfrequency of occurrence of cannibalism recorded in recent years (late 1970s to the\npresent) has usually been low (