Contribution to understanding the population structure and maturation of Illex argentinus (Castellanos, 1960): the case of the inner-shelf spawning groups in San Matias Gulf (Patagonia, Argentina)

CRESPI ABRIL, CÉSAR A.; MORSÁN, ENRIQUE M.; BARÓN, PEDRO J.

JOURNAL OF SHELLFISH RESEARCH

National Shellfisheries Association

Lugar: Grotton, Connecticut; Año: 2008 vol. 27 p. 1225 - 1231

0730-8000

Illex argentinus is known for spatiotemporally segregating into reproductive aggregations on the mid continental shelf and slope of southern South America. In this study we found that the species also mates and spwans in San Matías Gulf, a coastal basin off northeastern Patagonia. Basing on the analysis of size and maturity structure of squids caught over a twenty eight-month period in waters of the gulf, distinct demographic pulses were identified in the samples each year. Two of them were more consistent, one comprising small-sized individuals reaching full maturity in January-February (summer) and the other including larger individuals maturing between September and October/December (spring). Also, a less conspicuous group of mature individuals was observed in June/July (winter) of the last sampling year. So far, differences in the parameters of the size-at-maturity curves of these population components allow considering at least two stocks for management of I. argentinus in the gulf.