Laboratory observations on the foraging behavior of the Japanese common squid, Todarodes pacificus

Abstract:

Squid is a marine animal with extremely ferocious feeding. The foraging behavior of captive Japanese common squid, Todarodes pacificus, was filmed in a circular tank and analyzed. Three shoal sizes (3, 7-12, and 44 individuals) were examined. Squid attacking on prey fish were observed, and the angle ranges for prey detection and attack were found wide and narrow, respectively. The mean mantle length of the squid was 20 cm, and most attacks on prey began when the squid were 1 to 6 mantle lengths away. Squids displayed dark patterns during the attack phases, which could have been a sign of intra-specific communication. In the large shoal size, squid chased bigger prey, and several squid sometimes fed together on a single prey. This might be an alternative strategy when food was scarce.