INIDEP Informe Técnico, 51: 121p

INIDEP Informe Técnico, 51: 121p

Tringali, L.S.; Bezzi, S.I. eds. 2003. Aportes para la evaluación del recurso merluza (Merluccius hubbsi) al sur de los 41° S. Año 1999.

Contributions to evaluate the hake resource (Merluccius hubbsi) south of 41º S. Year 1999. Hake fecundity was estimated with the gravimetric method using ovaries, with hydrated oocytes without post-ovulatory follicles, of specimens obtained during time which coincides with the most important reproductive activity (December) in 1993, 1994 and 1996. Indices of prerecruits CPUE were obtained during April 1997 and 1998. Comparison of CPUEs indices showed that 1998 values were lower than those of 1997, which indicates there was no sign of stock recovery. Length‑weight and length-age relations at first sexual maturity were estimated, per sex. Length at first maturity at 50% was 33.79 cm and 35.38 cm for males and females respectively and age at first maturity was estimated in 2.61 and 2.67 years. Abundance indices of hake individuals age 2 was estimated in 1995-1998 period with data derived from research surveys programmed to that end. The spatial distribution of CPUE of age groups 1 and 2 in the area surveyed, total length distribution per survey and the corresponding age composition were presented. Hake age and sex structure of catches landed during the 1986-1998 and population for the 1993-1998 period were analyzed and a change in the exploitation pattern and the trend towards catching young individuals was observed. The activity of fishing fleets was described and density indices derived from research cruises and ice-chilling fleets were related and group between 1,400-1,800 HP related better to the abundance trend. A total CPUE for the region, which showed a declining trend during the period 1991-1997, was calculated. Discards of the commercial fleet directed to hake were estimated in weight and number of individuals. The dynamics of the ice-chilling and freezer fleets per area and quarter and processes of discarding were analyzed. Discards represented between 30% and 50% in weight and 11%-24% in number of catches. The status of hake (Merluccius hubbsi) resource was evaluated with the Biomass Dynamics Model of Pella and Tomlinson. Results indicate that the population was overexploited and in a low biological production level and catches always exceeded the surplus production corresponding to each year and the maximum sustainable yield. This was estimated at 244,773 t and the replacement catch at 147,389 t.