Browsing by Author "Bezzi, S.I."

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    Análisis y diagnóstico del diseño de muestreo de las campañas de evaluación de merluza (Merluccius hubbsi) al norte y al sur de los 41°S (Zona Comun de Pesca Argentino-Uruguaya y Mar Argentino). Años 1996-1999
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 2003) Hernández, Daniel R.; Bezzi, S.I.; Ibañez, P.M.
    Gain contribution by stratification in hake (Merluccius hubbsi) biomass estimation with respect to a simple random sampling based on the same sample size is analyzed. Considering as objective hake biomass assessment, curves which relate precision reached in estimations to the sample size are established. Data were from total hake biomass surveys carried out from 1996 through 1999 hake management units distributed North and South of 41°S Argentine Sea are analyzed separately. Stratification used at present allows to obtain very variable gains in precision associated to biomass with estimations, in the North management unit, with a maximun of 88 in 1996 and no gain in 1997. The South management unit presents also variable results but always with important gains. The applied sampling effort levels allow to obtain biomass estimation relative errors no higher than 29 in the assessment corresponding to the North management unit and 14 in the assessment relative to the South management unit. These values may be considered as very satisfactory. In the event of further diminishing estimation errors to obtain minimum gains it will be necessary to increase the sampling effort to levels which are inadmissible from a practical point of view. It does not seem feasible to diminish the present error of biomass estimation in both management units.
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    Aspectos biológico-pesqueros de la merluza de cola del Atlántico Sudoccidental
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1984) Bezzi, S.I.
    The distribution areas and population structure of the long-tailed hake are analized. Data come from fisheries research cruises carried out by RV Walther Herwig and Shinkai Maru in the Argentine Sea in 1978/79. Macruronus magellanicus is a typical cold waters species of the Southwest Atlantic and Southeast Pacific Oceans. Maximum concentrations were found in the southern Patagonian shelf, in coastal waters and in depths below 200 m. Spawning individuals were observed on the continental slope in the southern extreme of the Patagonian shelf (54°). The distribution area extend to 93,439 n mi² in spring and to 12,368 n mi² in summer.
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    Conocimiento biológico pesquero del recurso merluza (Merluccius hubbsi) y su pesquería en la República Argentina.
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 1995) Bezzi, S.I.; Dato, C.V.
    This paper summarizes the present knowledge on Merluccius hubbsi and its fishery in Argentina, based on the model proposed by the Technical Secretary of Comisión Técnica Mixta del Frente Marítimo, in 1990. It includes the taxonomic location of the species, its geographical distribution, stock unity, structure and population dynamics. It describes the fishing gear and fishing operations and presents the available information on selectivity and discards. The paper shows the data landings separated by fleet. Exploitation regulatory measures in force are included.
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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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    Report of the INIDEP working group on assessment of hake (Merluccius hubbsi) north of 48° S (Southwest Atlantic Ocean)
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 1994) Bezzi, S.I.; Cañete, G.R.; Pérez, M.; Renzi, M.A.; Lassen, H.
    The assessment covers hake between 34° and 48°S (Argentina and Uruguay), excluding Golfo San Matías. Total international landings and Argentine catch-at-age and effort data available for the 1983-1991 period allowed an analytical assessment. Tunning of the VPA was made using Laurec-Shepherd analysis and Extended Survivor analysis. The results of these analysis are congruent with the information about the state of the stock. VPA biomass estimates are aound 2.1 and 2.7 mill. Tonnes, which are similar to those calculated through surveys. The Spawning Stock Biomass estimated for 1991 is considered to be within limits where the stock shows stable recruitment. At the present effort level, yield and Spawning Stock Biomass appear to remain stable. Management measures are also discussed.