Dynamics of maturation, seasonality of reproduction and spawning grounds of the jumbo squid Dosidicus gigas (Cephalopoda: Ommastrephidae) in Peruvianwaters

In Peru, the giant squid Dosidicus gigas (D'Orbigny, 1835) is the most impo rtant cephalopod resource. The objective of the present paper is to analyse the reproductive cycle, and to determine the locations and potential of th e spawning of D. gigas off the Peruvian coast between 1991 and 1995. The si ze of the first stage of maturity was estimated at 240-320 mm for females. Mature individuals were observed throughout the entire study period, althou gh the main peak in spawning occurred between October and January with a se condary peak between July and August. An analysis of the seasonal cycle in spawning using maturity indices gave similar results and indicated the pres ence of two size groups with different maturity stages. Females were always more numerous than males during the study period and showed the highest in cidence of mating in spring (September-November). Spawning took place along the entire coast of Peru with the greatest numbers spawning in the norther n zone between 3 degreesS and 8 degreesS and the central zone between 12 de greesS and 17 degreesS. During 1993, there was an exceptional spawning grou nd in the southern zone during January and March. (C) 2001 Published by Els evier Science B.V.