Population structure and growth of the squid Illex illecebrosus (Cephalopoda: Ommastrephidae) off Nova Scotia, north-west Atlantic

Abstract

Population structure of the short-finned squid Illex illecebrosus (Ommastrephidae) was studied on the Nova Scotian shelf between July–September 1984. It was characterized by a prevalence of winter-hatched squid in summer–early autumn, their short (three months of the summer) occurrence on the shelf, and a predominance of females in sex ratios during the feeding period. Ages of squid were estimated by statolith increment counts and ranged from 128 to 201 d. Growth in length was described by linear model with daily growth rates of 0.99 mm/d−1. Adding the length-at-age data from juveniles caught in 1979 to the 1984 data set enabled to construct an ontogenetic growth curve for the winter-hatched squid which was best approximated by the Gompertz growth function.