2009 - INIDEP Informe Técnico Nro 68-77

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

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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.
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    Pesca comercial y captura por unidad de esfuerzo de la merluza (Merluccius hubbsi) entre 34º S-41º S durante el período 1986-2005 y evidencias sobre cambios en la distribución y composición por tallas del recurso
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 2009) Irusta, G.; Castrucci, R.; Simonazzi, M.
    The activity of the hake (Merluccius hubbsi) commercial offshore ice chilling fleet and its relation to concentration, distribution and population areas of the stock distributed between 34ºS - 41ºS is described. The catch per unit of effort (CPUE) for the 1986-2005 period was estimated applying the General Linear Model. Data derived from the offshore fishing logs provided by the Argentine Secretary of Agriculture, Farming, Fishing and Food Administration and the information obtained in research cruises carried out in 1994, 1996-2001, 2003-2005 to evaluate the resource population abundance. During the main fishing time in the sector (quarter 2) and up until 1991 the fleet scattered within the Argentine-Uruguayan Common Fishing Zone (SW Atlantic). Later on the activity concentrated south of 39ºS where catches and the nominal effort reached their maximum value to decrease northerly as a result of the depletion of stock concentration and the development of the hake fishery in the Patagonian area. The zone south of 39º S is a sector of low concentrations where adult individuals prevail and a transfer zone of the fleet towards Patagonian fishing grounds (41ºS - 48ºS). The annual CPUE estimated with the General Linear Model decreased by 49% in the study period. As of 2000 the fishery became variable as regards catches, fishing effort and operation areas and more dependent on important recruitments as a consequence of the marked decrease of adults population abundance.