Vertical distribution of hake Merluccius hubbsi in spawning aggregations in north Patagonian waters of the Southwest Atlantic

EHRLICH, M.; MACCHI, G. J.; MADIROLAS , A.; MACHINANDIARENA, L.

FISHERIES RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 138 p. 89 - 98

0165-7836

Argentine hake (Merluccius hubbsi) inhabit waters of the Southwest Atlantic Ocean between 34º and 54 º S, at depth ranging from 50 to 800 m. Two stocks have been identified in the Argentine shelf, the northern stock between 34º and 41º S and the southern one between 41º and 54º S. During cruises carried out in December 1996, 1998 and 2000 in the main spawning area of the southern stock, series of bottom and mid water trawls were conducted during daylight and darkness to assess vertical migration during spawning activity. In each haul hydroacustical data were recorded and a sample of ovaries was taken for maturity stages determination by histological analysis. In the 1998 and 2000 cruises, male segregation in hours of darkness was observed. Lack of actively spawning females at mid-water levels during darkness hours may be partly due to a reproductive courtship in which females could abandon the shoals during egg fertilization. Considering this behavior, we conclude that hake carried out diel reproductive vertical migrations.