Aplicación del método de producción de huevos para estimar la biomasa desovante de la población patagónica de anchoíta (Engraulis anchoita) en la primavera de 1998.

PÁJARO, M; SANCHEZ, R P; MACCHI,; ALEMANI, E; MICHAT,M; MILITELLI, M I

Trujillo

Congreso; VIII Congreso Latinoamericano sobre Ciencias del Mar.; 1999

The application of the daily egg production method to the assessment of the Patagonian anchovy population (Engraulis anchoita), in spring of 1998. Results are presented as a biomass estimate of the patagonian spawning stock of Engraulis anchoita, in 1998. An exploratory cruise was carried out in December, for the assessment of the Patagonian stock, by means of acoustics and the daily egg production method (DEPM). The study area extended from 41°S to 45°S. The spawn ground comprised about 60,000 km2. In this area the reproductive activity is dependent on the formation of tidal fronts. 68 PAIROVET samples were analyzed to estimate daily egg production. Adult parameters, spawning fraction and fecundity, were based on the analysis of samples obtained on the cruise. Mean egg production was 160 eggs/day/m2, relative batch fecundity was 426.1 eggs/g and spawning frequency was 0.16. DEPM estimate of spawning biomass was 298,332 t. This estimate was the lowest value obtained for the last 6 years. This result could be consequence of a migration of the spawning schools out of the study area, and an evident increment of the gelatinous zooplankton that could predate the anchovy eggs.