Browsing by Author "Irusta, G."

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    Aplicación de un modelo dinámico de biomasa para evaluar el efectivo sur de merluza. Período 1986-1998
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 2003) Irusta, G.; Hernández, Daniel R.
    The status of hake (Merluccius hubbsi) resource south of 41°S in the Argentine Sea was evaluated with the Biomass Dynamic Model of Pella and Tomlinson. Results indicate that the population was overexploited and in a low biological production level (B99 BMSY1 because, as of 1998, catches always exceeded the surplus production corresponding to each year and the (MSY) Maximum Sustainable Yield. In 1993 increase of landings accelerated declination of biomass. For 1999 the MSY was estimated at 244,773 t and the replacement catch at 147,389 t. Landings corresponding to 1998 surpassed the MSY in 145,000 t and the replacement catch in 242,611 t.
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    Pesca comercial de merluza al sur de 41°S y estimación de índices de abundancia derivados de la flota pesquera
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 2003) Irusta, G.; Pérez, M.; Renzi, M.A.; Castrucci, R.
    The activity of fishing fleets for hake Merluccius hubbsi south of 41°S Argentine Sea, SW Atlantic, is described. In order to establish the standard group of vessels, density indices derived from research cruises and ice-chilling fleets were related. Group four 1,400-1,800 HP related better to the abundance trend. Also, two series of indices associated to different fractions of the population were estimated: juveniles age 2) and adults age 3-5. Finally, a total catch per unit effort CPUE for the region south of 41°S, which showed a declining trend during the period considered 1991-1997, was calculated.
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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.