RESUMEN.En el golfo San Jorge se desarrollan varias actividades económicas de relevancia, entre ellas dos pesquerías industriales: la pesquería de merluza común (Merluccius hubbsi Marini, 1933) y la pesquería de langostino patagónico (Pleoticus muelleri Bate, 1888), ambas se solapan espacial y temporalmente. En la pesquería de merluza del golfo San Jorge opera una flota fresquera de altura, compuesta por unas 20 embarcaciones, y una flota costera, compuesta por unas 30 embarcaciones. En esta pesquería se pesca alrededor del 10% de lo capturado en el stock sur de merluza. En la pesquería de langostino del golfo San Jorge opera una flota congeladora tangonera compuesta por 80 embarcaciones, responsable de más del 75% de los desembarques de langostino realizados en la República Argentina. Ambas pesquerías tienen como principal problema la captura incidental de merluza, en una de sus principales áreas de cría. En el presente trabajo se describe el manejo actual en las pesquerías del golfo San Jorge, el cual consiste principalmente en cierres espaciales y temporales para la pesca de langostino, y zonificaciones por estrato de flota para la merluza. En ninguna de las dos pesquerías descriptas se han tomado medidas que reduzcan eficazmente la captura incidental. Palabras clave: pesquerías, merluza común, langostino patagónico, descarte, golfo San Jorge, Argentina. Characterization of the main fisheries in San Jorge Gulf, Patagonia, ArgentinaABSTRACT. In San Jorge Gulf, several important economic activities are developed, including two industrial fisheries: hake (Merluccius hubbsi Marini, 1933) and Argentine red shrimp (Pleoticus muelleri Bate, 1888). Both overlap spatially and temporally. The San Jorge Gulf hake fishery consists of a high-seas ice trawler fleet (n = 20 fishing vessels) and a coastal fleet (n = 30 fishing vessels). These fisheries capture about 10% of the catch of the southern hake stock. The Argentine red shrimp fishery consists of a double-beam trawler fleet with 80 freezer vessels, responsible for more than 75% of shrimp landings in Argentina. The main problem of both fisheries is the bycatch of hake in one of its principle nursery areas. The present work describes the current management of the fisheries of San Jorge Gulf, which consists primarily of spatial and temporal closures for the Argentine red shrimp and zoning by stratum of the fleet for hake. Neither of these two fisheries has taken measures that effectively reduce bycatch.

The relationship of body weight and total length (L T ) of Mustelus schmitti in southern Patagonia was different between sexes. Changes in maturity stages in males appear at larger sizes in Ría Deseado specimens than in the Mar del Plata area. Mature females ranged from 795 to 913 mm while all male specimens >759 mm L T were mature. The data suggest that mating occurs before parturition, with simultaneous ovulation. The diet of adult M. schmitti was mainly carcinophage and the diet of young-of-the-year and adults differed. The youngof-the-year use the Ría Deseado as a pupping area. 2000 The Fisheries Society of the British Isles

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. University of California Press and CooperOrnithological Society are collaborating with JSTOR to digitize, preserve and extend access to The Condor. Abstract. We analyzed the effect of the shrimp fishery on Magellanic Penguins (Spheniscus magellanicus) in two ways: (1) we determined whether penguins were incidentally killed and the magnitude of incidental take, and (2) estimated the overlap between penguin diet and fish by-catch of the shrimp fishery (total capture excluding shrimp and seabirds). We worked with the fishing fleet operating at Golfo San Jorge with onboard observers over 200 days in 1995-1997, sampling fishery by-catch and entangled birds. Penguins were affected during the austral summer. Estimations of mortality rates showed 0.33% of the breeding population at Golfo San Jorge is incidentally killed by the shrimp fishery every summer. By-catch in shrimp fishery nets was composed of species important as penguin prey (anchovy and hake) in higher proportions during summer. The daily by-catch of these species was higher than the total calculated daily intake for all penguins breeding in the Golfo San Jorge. This could have a significant effect on birds. We recommend that an observer program be implemented to monitor seabird mortality and that fishing gear should be improved to reduce the indirect effect of the fish by-catch on penguins.

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This work recorded discards of by-catch (mainly Argentine hake Merluccius hubbsi) from the Patagonian red shrimp (Pleoticus muelleri) fishery in San Jorge Gulf, Patagonia, Argentina, and evaluated the effectiveness of a shrimp-selectivity device. By-catch species are listed, together with percentages of biomass per species and frequencies of occurrences in tows. Biomass ratios of total by- catch:shrimp and hake:shrimp caught were calculated by area and by season. In experimental tows comparing the effects of grids in the codends of the nets, two grids per codend (bar spacing 47 mm and 25 mm) excluded part of the by-catch, but captures of shrimps were also lower than with a single grid (47 mm bar spacing) per codend. Resumen. En el presente trabajo, se evalúa la composición específica y la biomasa de fauna acompañante de la pesca del langostino patagónico Pleoticus muelleri del Golfo San Jorge (Patagonia, Argentina). Los datos fueron obtenidos por medio de muestreos llevados a cabo por observadores a bordo entre 1995 y 1997. Se presenta una lista de especies acompañantes, junto con los porcentajes de biomasa por especie y frecuencia de aparición en los lances. Para cada área y estación se calcularon las tasas de fauna acompañante total y de merluza común (Merluccius hubbsi) por kg de langostino obtenido. La merluza común es la especie de mayor presencia en los lances. Se efectuaron experimentos en base a modificaciones del arte de pesca normal, comparándolo con el DISELA II (INIDEP), con dos grillas, y con un arte de una sola grilla. El DISELA II excluye parte de la fauna acompañante, pero afecta al volumen de langostino capturado. El arte de una grilla excluye menos langostino, pero también menos fauna acompañante.