INIDEP Informe Técnico Nº 8 – 1996

INIDEP Informe Técnico Nº 8 – 1996

Evaluación del efectivo bonaerense de anchoíta (Engraulis anchoita) entre las latitudes de 34° y 38° S en el otoño de 1994.

Autores: Jorge E. Hansen, Adrián O. Madirolas y Ricardo G. Perrotta.
Contribución INIDEP 956


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Citar como:
Hansen, J.E.; Madirolas, A.O.; Perrotta, R.G. 1996. Evaluación del efectivo bonaerense de anchoíta (Engraulis anchoita) entre las latitudes de 34° y 38° S en el otoño de 1994. INIDEP Informe Técnico 8, 45 p. Disponible en: http://hdl.handle.net/1834/7038.

Summary

Bonaerensis anchovy (Engraulis anchoita) stock assessment between the latitudes 34° and 38°S carried out during the autumn 1994. A pre-stratified acoustic sampling of the area between 34°- 38°S, at depth 10-100 m was performed during May 1994 to assess anchovy (Engraulis anchoita) biomass. A SIMRAD EK-500 system operating with a split-beam 38 KHz transducer was used. A Mid Water Trawl net (Nichimo net: 30.8 m headrope, 10 mm meshed at the inner cover of the codend) was employed to identify echotraces and to collect anchovy samples. Anchovy biomass was evaluated to be about 2.06 millon tons. About 50 o/o of that figure correspondend to either juveniles or pre-adult fish (up to 105 mm total length), which widely dominated in number of individuals, mainly in shallower waters. Adults fish were more abundant within the strata 3 and 4, as noticed during a survey carried out in May 1983. Other biological estimates, such as size-at-50 o/o maturity (about 11 cm total length), and both natural and total mortality rates (M=0.81; Z=1.09) were also found to be in agreement with previous studies on the same population.