Life history of Patagonian squid Loligo gahi and growth parameter estimates using least-squares fits to linear and von Bertalanffy models

Abstract

Size and sexual maturity of a large number of Loligo gahi Orbigny 1835 from commercial trawler catches around the Falkland Islands were recorded. Data are explained by proposing that the squid have a 1 yr lifespan and that the population consists of 2 stocks, one spring-spawning and one autumn-spawning. Degree of mixlng between the stocks was not assessed. Lnear and von Bertalanffy equations are used to model the growth of the spring-spawning stock. Both models fit the data nearly equally well, the linear fit yielding slope = 0.0237 for males (0.0199 for females) cm dorsal mantle length d-' growth rate and the von Bertalanffy fit yielding K = 0.00304 (0.00308) d-l, L , = 19.6 (17.8) cm, to = -101.4 (-113.6) d from 1 Jan. This growth rate is surprisingly fast given the cold water temperatures around the Falklands, and suggests that food was plentiful for this species.