Food of the squid Nototodarus gouldi in Bass Strait

Abstract

A study was carried out on the food of the squid N. gouldi, based on 1277 individuals collected by Japanese vessels jigging in Bass Strait from November 1979 to April 1980. Most of the food consisted of crustaceans, fish and cephalopods, with crustaceans being more common in smaller animals and cephalopods in larger ones. The crustaceans, which included several benthic species, were more common in the diet at night than by day. Cannibalism by N. gouldi did not appear to increase appreciably after the animals were brought aboard and laid together in the collecting troughs. By frequency of occurrence, the contributions to the diet, averaged over all sizes sampled, were fish 37%, crustaceans 36%, and squid 26%; but in terms of biomass fish contributed more. From the size of the beaks of squid taken, it could be shown that the mantle length of these prey was usually not more than half that of the predator. N. gouldi feeds primarily at night, probably moving up from the bottom into the water column. Larger specimens, both male and female, were less likely to contain food in the stomach than smaller ones, and possible explanations are considered. There are some indications about the timing of spawning in 1979-1980, from records of the size and sexual maturation of the animals sampled.