Volumen 42 - Número 3: 345-356 | 2007
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Spatial variations of the Argentine hake (Merluccius hubbsi (Marini, 1933)) spawning shoals in the Patagonian area during a reproductive season  

Gustavo J. Macchi^1,2*, Marcelo Pájaro² and Claudia Dato²

¹Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rivadavia 1917 (1033), Buenos Aires, Argentina
²Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), Paseo Victoria Ocampo N° 1, CC. 175, Mar del Plata (7600), Argentina

*This email address is being protected from spambots. You need JavaScript enabled to view it. 

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.

Key words: Merlucciidae, southwest Atlantic Ocean, reproduction, migration