Browsing by Author "Renzi, M.A."

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    Aspectos biológico-pesqueros del abadejo (Genypterus blacodes)
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1986) Renzi, M.A.
    The kingklip is one of the species that has been traditionally exploited in the Argentine Sea. Although captures were not very important, they have been increased in the last years. In this paper, the structure of the concentration areas of summer, spring and winter distribution and other biological aspects were analyzed, on the basis of the data collected during cruises carried out by R/V "Walther Herwig" and R/V"Shinkai Maru" in Argentine waters during 1978/79. The trophic spectrum of the kingklip comprises mainly food species of the Classes Pisces and Crustacea as well as other complementary groups like Mollusca, Brachiopoda and haliacea.
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    Crecimiento de la merluza (Merluccius hubbsi) del Atlántico sudoccidental entre 1993-2003 al norte y sur de 41º S
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 2009) Renzi, M.A.; Santos, B.A.; Abachian, Viviana
    The reading of otoliths sagittae collected during the INIDEP (National Institute for Fisheries Research and Development, Argentina) assessment cruises carried out in the 1993-2003 period allowed to estimate length and weight growth parameters and the condition factor of hake (Merluccius hubbsi) and to prospect the two management units of the species north and south of 41ºS (Argentine Sea, SW Atlantic). A great variability in total length and weight in each age group was observed; nevertheless, stable mean length and weight values per age group were observed in the period analyzed. Besides, the values estimated to determine possible growth variations in each and between both management units north and south of 41ºS were compared. The comparison of growth curves of males and females in each area showed highly significant differences. When each sex between stocks was compared, some years those differences were observed for growth as a whole and only for some parameters in others.
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    Estructura por edad y sexo de la captura de merluza desembarcada. Período 1986-1998
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 2003) Renzi, M.A.
    During the 1986-1998 period the hake (Merluccius hubbsi) fishery in the Argentine Sea (SW Atlantic) turned from moderate to intense exploitation. Age and sex structure analysis showed a change in the exploitation pattern. During the three periods defined 1986-1989, 1990-1992 and 1993-1998 a trend towards catching young individuals and a predominance of females age 3 and older was observed. An increase of total mortality was also detected. As a consequence of the establishment of a closed area in mid 1997 ice-chilling and freezer fleets changed operation areas which brought about differences in the catch structure. Freezers showed higher percentages of older ages. An average decrease of 30 in yield number of individuals per unit effort for all ages was also observed.
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    Estructura por edad y sexo de la población de merluza
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 2003) Renzi, M.A.; Santos, B.A.; Simonazzi, M.
    Hake Merluccius hubbsi population structure in 1993, 1994, 1996, 1997 and 1998 and age and sex distribution during 1997 are analyzed. Data were obtained in research surveys. At the end of winter 1997 concentrations of juveniles were found in the San Jorge Gulf Argentine Sea, SW Atlantic, with maximum yields of 10,000 individuals per trawl hour for age 1 and 2,500 individuals per trawl hour for age 2. The highest concentrations of adults were found in the Gulf and South of 47°S, between the 100 and 200 m isobath, maximum yields of up to 1,700 individuals per trawl hour for age 3 and up to 90 individuals per trawl hour for age 7 and older. In spite of the decrease in population abundance, the basic age structure juveniles, young adults and old adults was stable in the period studied. Sex ratio of total population was approximately 1:1. Nevertheless, when sex and age proportion was estimated it was observed that, as of age 3, females were more abundant than males. The highest mortality rates for both sexes in the 1996-1997 period were observed in ages 3 and 4in 1997-1998 they corresponded to ages 6 and 7.
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    Growth in the 0-group of Argentine hake (Merluccius hubbsi) from the Argentine-Uruguayan Common Fishing Zone
    (Mar del Plata : Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 2006) Santos, B.A.; Renzi, M.A.
    Growth of hake (Merluccius hubbsi) in the 0-group from the Argentine-Uruguayan Common Fishing Zone was studied and spawning data were back-calculated by identifying daily growth rings in otoliths of specimens caught during research cruises performed in May 1997, May 1998 and June 1999. Total length (TL) range was 14-69 mm. Increments were read under microscope using an otolith daily ring measurement system (RATOC). Changes in the increment width data present a pattern that seemed to be similar, and independent from birth date of individuals. Data observed and back-calculated showed good accordance with the Laird-Gompertz model. Significant differences between coefficients were found in all comparisons of growth curves for observed and retrocalculated data. Growth rates estimated from observed data showed maximum values (ca. 0.54 mm d-1) at the stage of late larvae and minimum values at the stage of large early juveniles (ca. 0.25 mm d-1). For each year back-calculated hatching dates corresponded to the scarce mid-summer reproductive activity.
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    Índice de abundancia del grupo merluza de edad 2 en el área de cría patagónica. Período 1995-1998
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 2003) Castrucci, R.; Aubone, Aníbal; Pérez, M.; Renzi, M.A.
    An abundance index of hake Merluccius hubbsi individuals age 2 was estimated in the nursery area south of 41°S Argentine Sea, SW Atlantic. The analysis comprised the 1995-1998 period and was made with data derived from research surveys programmed to that end. A mean value estimator of CPUE catch in number of individuals per trawl hour based on delta distribution was used. The spatial distribution of CPUE of age groups 1 and 2 in the area surveyed, total length distribution per survey and the corresponding age composition are presented. The declining trend of abundance index of hake age 2 observed during the four year period amounted to 52.9.
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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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    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.