Browsing by Author "Giussi, A.R."

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    Evaluación de merluza de cola (Macruronus magellanicus) en el Atlántico Sudoccidental. Período 1985-2001
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 2007) Wöhler, O.C.; Hansen, J.E.; Giussi, A.R.; Cordo, H.D.
    Period 1985-2001. A stock assessment of Patagonian hoki of the Southwest Atlantic was carried out by using data from the years 1985-2001. A cohort analysis, fitted with some survey abundance indices was used in an adaptive conceptual framework. Simulation trials were performed to project the evolution of the fishery, to evaluate the risk of over-fish the stock under different exploitation levels, and to estimate Biologically Acceptable Catches (BAC). Both total biomass and spawning stock biomass showed increasing trends resulting from four strong year classes (1993, 1995, 1996 and 1998). Total biomass at the beginning of 2001 was estimated to be 2.5 million tons, and spawning stock biomass at the spawning time (August) was estimated to be around 1.28 million tons. The exploitation rate was low (0.19) and showed a decreasing trend in relation to previous years. The fishing mortality rate producing sustainable total catches in the long term, i.e., BAC corresponded to yields between 160 and 306 thousand tons during 2002, depending on future levels of recruitment
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    Grenadiers (Pisces, Macrouridae) of the southwest Atlantic ocean: biologic and fishery aspects
    (Mar del Plata : Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 2010) Giussi, A.R.; Sánchez, F.; Wohler, O.C.; Bernardele, J.C.
    Several grenadier species distribute in the SW Atlantic Ocean. Macrourus carinatus and Caelorinchus fasciatus are more frequently identified in commercial catches and during research cruises. Those benthopelagic fishes, related to subantarctic waters, inhabit at depths beyond 200 m and in high seas, between 36º S-59º S. During the surveys carried out on board of Argentinean research vessels, M. carinatus was present in 4% of the trawls performed. The highest densities (>17 t nm-2), obtained between 360-380 m depth, at 39º S, decreased significantly southwards. C. fasciatus was caught in 6% of the total trawls and the highest densities (15-35 t nm-2) were found at depths beyond 200 m, south of 52º S. Due to the difficulty encountered to identify them, in fishing statistics they are grouped as ‘Grenadiers’. Nevertheless, in many cases, the correct identification by scientific observers on board of commercial vessels provides useful information to support the data gathered. Grenadiers are caught as by-catch in important fisheries that have the main fishing grounds south of 52º S. Historically, different countries participated in the fishery that shows two evolution periods. In the first, exploitation carried out mainly by vessels from the former USSR reached a maximum of 31,000 t in 1984. In the second, the Argentine fleet caught up to 10,000 t in 2000. At present, freezer and factory trawlers obtain 88% of the catches and longliners 10% of the total.