Spatial variations of the Argentine hake (Merluccius hubbsi) spawning shoals in the Patagonian area during a reproductive season

MACCHI, G.J.; PÁJARO, M.; DATO, C.

Revista de Biología Marina y Oceanografía

Instituto de Oceanología, Universidad de Valparaíso

Lugar: Valparaíso; Año: 2007 vol. 42 p. 345 - 356

0080-2115

Displacements of Argentine hake Merluccius hubbsi shoals in the spawning area of Patagonia before and during a reproductive season were analyzed. In particular, monthly changes in fish density, sex composition, size structure and spawning location were described for this stock. During October-November hake shoals moved from deeper waters to the coast at about 44°S, where spawning took place in December. During January the main reproductive aggregations stayed near the coast (50 m depth) but displaced to the southern area (45°S); in February spawning activity diminished and spent females began to return to deeper waters. In general, this process was first completed by young spawners (35-45 cm TL), which have a breeding season shorter than the old females. We observed that males arrived at the spawning area first and remained there for a longer period than females. During the reproductive period skewed sex ratios in different sampling sites were observed. These differences in sex composition were attributable to: 1) local segregation produced by the reproductive behavior of hake, in which males form groups with a single female, and 2) migration of spent females to deeper waters, which causes male-biased samplings in coastal areas.