Alimentación de Merluccius hubbsi e impacto del canibalismo en la región comprendida entre 34°50'-47°s del Atlántico Sudoccidental.

Abstract

Feeding of Argentine hake during winter 1994, between 50 and 370 m of depth, in the studied area (34°50'-47°S), is based on the consumption of zooplanktonic crustaceans, fishes and cephalopods. Maximum feeding incidence is found at 36°-40°S (51. ), in sea layer of 80-130 m deep (62. ) and between 8:00-10:00 hours (36,6. ). Cluster analysis shows five spatial groups, with similar length distributions and characteristic principal prey items combination. The males of all sizes show a trend to feed on euphausids and hiperiids amphipods. The females eat more quantities of hake, short fin squid and other fishes. There is a change in diet related with predator size, from 47 cm TL onwards for males, and from 53 cm TL for females. This change consists in a decrease of macrozooplanktonic crustacean consumption and an increase of fish in diet. There is a decrease in the predation of all preys, with the increase of the depth, except for mictophids fishes, which prevail from 130 m onwards. During the morning hours, all prey items show maximum values in stomach contents. The midday feeding is related with the water layer close to the bottom layer, when hake principally consumes bentic macrocrustacean. Southerly of 44°S the intake of fishes and cephalopods increases. From total hake cannibalized number, 95,7. corresponds to those hakes smaller than 24 cm TL (ages 0 to 2), which were predated by hake group among 35-. 49 cm TL (ages 2 to 7). Cannibals size is between 15 and 81 cm TL (ages 0 to 10)and 47. of them belonged to ages 0 to 2. Cannibalism was greater between 34°-39°S, at depth less than 100 m of depth, where bigger juvenile stocks are concentrated.