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Veuillez utiliser cette adresse pour citer ce document : http://hdl.handle.net/1834/2529

Titre: La caballa (Scomber japonicus) y las condiciones ambientales en el area bonaerense de El Rincón (39°- 40°30' S), agosto 1996.
Autre(s) titre(s): Mackerel (Scomber japonicus) and the environmental conditions in the Buenos Aires shelf area of "El Rincón" (39°- 40° 30' S)
Auteur(s): Perrotta, R.G.
Madirolas, A.
Viñas, M.D.
Akselman, R.
Guerrero, R.A.
Sánchez, M.F.
López, F.
Castro Machado, F.
Macchi, G.J.
mot-clé ASFA: Abundance
Biomass
Population structure
Zooplankton
Environmental conditions
Echo surveys
Date de publication: 1999
Editeur: Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero
Référence bibliographique: INIDEP informe técnico, 26. p. 1-29
Résumé: In August 1996 acoustic methods were employed to estimate mackerel (Scomber japonicus) abundance in the Buenos Aires, Argentina shelf area of "El Rincón" (4,287 mn2), located between 39°- 40° 30' S. Results showed a biomass estimate of 77,260 t. ASIMRAD EK-500 equipment operated with a 38 KHz split-beam transducer was used. Midwater fishing trawls were employed to identify echotraces and to collect mackerel samples.Trawls 4 and 5 were the most successful. Samples included only adult fish (310-470 mm Lt and ages ranging 2-11). Length and weight growth parameters and mortality rates were estimated. Analysis of the stomach contents revealed that mackerel was feeding exclusively on zooplankters over 2 mmlength. The analysis of the characteristics (dimensions and density) of the mackerel shoals allowed to detect two areas of concentration above and below 40°S latitude. The northern area was characterized by relatively small schools of medium density similar to those of the Mar del Plata area. In the southern zone, large schools of high density that account for almost 92 of the total biomass were found.Differences between both areas were also detected when plankton distribution was analyzed. Higher abundances of the dinoflagellate Alexandrium tamarense corresponded to the southern area. On the contrary, higher zooplankton biomass was detected northerly of 40°S. From an oceanographic standpoint, the presence of mackerel was associated to relatively higher salinity values. As a result of the different data analyzed it is suggested that,during this time of the year, the species shows a migratory pattern from the intermediate shelf to coastal areas.
URI/URL: http://hdl.handle.net/1834/2529
ISSN: 0327-9642
Collection(s) :2. INIDEP Informe Técnico

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