2009 - INIDEP Informe Técnico Nro 68-77

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Browsing 2009 - INIDEP Informe Técnico Nro 68-77 by Subject "Biomass"

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    Estimaciones de la biomasa de merluza (Merluccius hubbsi) en los sectores argentino y uruguayo de la Zona Común de pesca argentino-uruguaya (34º 00º S-39º 30º S) Y en el área que se extiende hasta 41º S (ZEE Argentina) en 1994, 1996-2001 y 2003
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 2009) Bezzi, S.I.; Ibáñez, P.M.
    Hake (Merluccius hubbsi) biomass in the Argentine and Uruguayan sectors of the Argentine-Uruguayan Common Fishing Zone (AUCFZ) and in the area that extends from the limit of the shared zone to 41° S was estimated (SW Atlantic Ocean). The contribution to the strata total biomass in each sector was analyzed and complemented with observations on the structure of the population. The basic data to estimate biomass derived from the evaluation surveys of the Hake Project carried out in winter or spring 1994, 1996-2001 and 2003. In 1999 biomass north of 41° S decreased to 30. (112,280 t) of the estimates made for 1994. In 2000 it increased to 165,000 t and in 2003 it was estimated at 156,407 t. A remarkable decrease of the AUCFZ percentage of contribution to the total biomass north of 41° S was registered. The result was an increase of the contribution corresponding to the intermediate zone that in 2003 contributed 54. of the total biomass. The modal class was equal to or smaller than 25 cm in the Uruguayan sector, between 13-37 cm in the Argentine sector and smaller than 35 cm in the intermediate zone where it reached 22 cm in 2000 and 27 cm in 2001. The rest of the years it varied between 38-41 cm. In the intermediate zone the average length and the modal class were larger than in the AUCFZ sectors.
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    Muestreo de desembarque de caballa (Scomber japonicus) en el puerto de Mar del Plata, período noviembre 2003-diciembre 2004 y resultados de la campaña de estimación de la biomasa de diciembre de 2004
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 2009) Perrotta, Ricardo G.; Garciarena, A. David; Madirolas, A.; Cabreira, Ariel G.
    Chub mackerel (Scomber japonicus) landings corresponding to November 2003-January 2004 and November 2004-January 2005 fishing seasons were analyzed at the Mar del Plata port (Argentina, SW Atlantic). Fourty one samples were taken to measure total length exclusively and 4 sub-samples to record individual data (total length, weight, sex, sexual stage, age according to otoliths reading). Total length ranged 20-50 cm (1 and 8 years old). The most abundant sizes, between 32-37 cm, corresponded to ages 3 and 4, respectively. Most of the fish caught were adult (95%) and mature (85%) specimens. Length-weight, length-age relations were calculated and length-growth, weight-growth parameters estimated. The catch per unit of effort, of high variability (0-2,455 kg h-1), decreased as sea surface temperature increased. To estimate the species biomass in the fishing area a research cruise was carried out between 17-20 December 2004. Measurements, obtained with acoustic methods, reached a total of 11,678 t. The highest concentrations were found at a temperature of around 17.4 ºC and salinity of 33.62 psu. During the acoustic tracking, unusual concentrations of anchovy for the season were detected.