Identificación de las primeras marcas de crecimiento en los otolitos de juveniles de castañeta Cheilodactylus bergi (Pisces:Cheilodactylidae).

Abstract

Hyaline or slow growth rings were identified in juvenile castañeta otoliths Cheilodactylus bergi, with the aim of establishing an objective criteria for age determination in this life stage.Samples were obtained from four research cruises carried out between 1988 and 1991 in the north-patagonian continental shelf and Argentine-Uruguayan Common Fishing Zone (CFZ)(SW Atlantic, between 34° and 47°S). Through measurement of sagitta otoliths, the existence of three hyaline rings was determined. The one closer to the nucleusis formed during the first winter in the fish life or when larval metamorphosis occurs (1-2 months after spawning peak). The second ring was related to the transitional period between postlarvae and juvenile. This involves a habitat change, from pelagic to demersal life. It would be formed in the warm season at a fish age of 8-10 months. The third hyaline ring is related to the first regular annual ring, which is formed during winter at an approximate age of 16-19 months.