ANALYSIS ON BIOLOGICAL CHARACTERISTICS OF THE CATCH OF SQUID JIGGING IN THE SOUTHWEST ATLANTIC

Based on the surveys of squid jig operation in the Southwest Atlantic in 2000, an analysis on biological characteristics of the catch - Illex argentinus is reported in the paper. The results show that 1) The ratio between males and females, the sexual maturity and the mantle length at maturity of females of the catches are quite different around March on high sea fishing ground, So it is suggested that the catch around March are composed of two stocks on high sea fishing ground in which the catch in Jan. and Feb. is mainly composed of summer- spawning stock(SSS), and the catch after Mar is replaced by south Patagonic stock(SPS). The ratio between males and females, the sexual maturity and the mantle length at maturity of females of the catches show that the catch in Falklands waters and the catch in high sea after Mar. are all composed of SPS; 2) The mantle length of the catch grows larger with time goes by and consequently the size of hooks and lines should be adjusted in accordance with different fishing seasons; 3) Illex argnetinus mainly feed at night, especially at nightfal and before dawn, and such time may be the best time for fishing.