What makes the Southwest Atlantic hake (Merluccius hubbsi) so resilient?

EHRLICH, M.; MACCHI, G. J.; PÁJARO, M.; MACHINANDIARENA, L.; BROWN, D.; BETTI, P.

Vancouver

Congreso; International Congress on the Biology of Fish; 2006

University of Newfoundland

Argentine hake is the most important demersal species in the SWA and is heavily fished with cleare signs of overfishing as catches are sustained by decreasing spawning biomass and a few age groups. However stock remains, and annually a mean catch (1992-2002) of 423,586 t was landed. There are two identified fishing stocks, limited by the 41º S parallel. There are some features corresponding to reproduction and early life history which can explain this hight resilience. Hake has many spawning grounds in the Argentine shelfand an extended reproductive season from december to march in the south stock and from march to june in the north stock. Hight batch fecundity ranging from 100,000 to 2,300,000 hydrated oocytes, and a spawning frequency from 7 to 10 days. Total egg production ranged between 855 x 1012 eggs in the peak of southern stock spawning season to 39 x 1012 eggs at the end .There are noticeable differences in larval growth between both stocks. The larval development is very fast and a larvae of 29 mm total lenght has completed the definitive fin structure and a functional wide mouth is acquired at 3 mm. At 20 mm the larvae starts settlement and daily vertical migration sharing a pelagic and bottom food and protection environment. All this features accounts that hake is a r strategist which can find favorable conditions for survive and growth.