Browsing by Author "Perrotta, R.G."

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    Algunas características de la estructura y del comportamiento migratorio de los cardúmenes de caballa (Scomber japonicus marplatensis) en la plataforma bonaerense (Mar Argentino) : período 1965-1984
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1987) Cousseau, M.B.; Angelescu, Víctor; Perrotta, R.G.
    Three periods were distinguished during the analyzed years: the first one (1965-1975) may be defined as "normal fishing seasons" occurring from October to March, with catches between 8,000 and 14,000 tons.
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    Comparación mediante el empleo de los caracteres merísticos y el crecimiento de caballas originarias de varias regiones geográficas (Cataluña, Islas Canarias y Sudamerica)
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 1993) Perrotta, R.G.
    Mackerel from SW Atlantic (22° -39°S) and the coast of Cataluña (42° 30'N) were compared by analizing both morphometric and meristic characters. A multivariate analysis, i.e. principal components was used. The growth curves corresponding to mackerels from different regions (Canarias, North of Chile, Mar del Plata and Rincón in Argentine) were also compared, as well as the mean length at ages 1 and 2 (Mar del Plata- Cataluña, Rincón- Cataluña). Significant differences in the growth were found between two groups. The first group was integrated by three SW Atlantic population (Brasil, Mar del Plata, Rincón), which possible conform a subspecies of Scomber japonicus. The second one was represented by the coastal mackerel off Cataluña.
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    Distribución y estructura poblacional de la polaca (Micromesistius australis)
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1982) Perrotta, R.G.
    The polaca (Micromesistius australis)is a typical fish from the cold Malvinas current (temperatures between 3° and 10°C). The species is found in depths between 90 and 800 m and in latitudes from 37°40' to 50° S during winter and spring and from 42°S to 55°S during summer time, over the patagonian shelf and Burdwood Bank. One part of the stock reaches the southern region of the Scotia Sea, the western South Georgias and eastern South Shetland Islands. The dominant food species are Euphausia spp. The polaca is mainly a carcinophagous fish and may be found in a 3-4 trophic level, being one of the main food sources for primary and secondary ichthyophagous fishes.
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    Evolución reciente de la captura por unidad de esfuerzo (1993-2004) y de las tallas medias (1993-2005) del pez palo (Percophis brasiliensis) en el litoral marítimo entre 34º S y 42º S
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 2009) Rico, María Rita; Perrotta, R.G.
    Brazilian flathead (Percophis brasiliensis), of wide latitudinal distribution (23° S-47° S), is caught in Argentina in two coastal areas north and south of the Province of Buenos Aires delimited by the 39° S latitude. The species shows the highest abundance and catch yield percentages ( 5. ) of all coastal fish groups. The importance of the species makes it necessary to analyze mean lengths and define an annual abundance index that would allow to diagnose the state of the stock. To calculate the index the General Linear Model was adjusted. The factors used were Year, Quarter and 4 sub-areas, all statistically significant. The problem generated by the presence in the model of first order interactions that include the Year factor is discussed. It is concluded that the catch per unit of effort series did not represent changes in the resource abundance. Results suggest that caution should be taken when using the values normally considered to diagnose the state of the stock and implement management measures. Based on catch and effort values, the most important sub-areas were the mouth of the Río de la Plata river (1) and the Mar del Plata adjacent areas (3). A decreasing trend of the mean length throughout the study period was also observed.
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    Resultados de una campaña de investigación sobre la anchoíta (Engraulis anchoita) del sector bonaerense en el otoño de 1983. Distribución, abundancia y algunos aspectos biológico-pesqueros
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1986) Hansen, J.E.; Gru, D.L.; Perrotta, R.G.
    An extensive area of the continental shelf -between 37°20' and 34°40'S - was reviewed through hidroacoustical methods in order to evaluate the anchovy biomass. Within the area of highest concentration, further data on anchovy abundance were recorded, and fish samples were taken. Large anchovy shoals were located at about 170 nm from Mar del Plata, mainly in zones with sharp changes in oceanographic conditions. The distribution of the species was not uniform, but "contagious", and the log-normal distribution provided the best fit for the echo-integrator recorded data. The biomass was estimated at 1,061,727 tons (Confidence limits in between 921,010 and 1,223,930 tons). Some parameters of the population were estimated, such as: lenght-weight relationship, von Bertalanffy growth curve constants, sex ratio, maturity, and age composition. Taking into account a calculated naturaly mortality rate of M= 0.85, a Maximum Sustainable Yield at about 451,000 tons was estimated (Confidence limits at about 520,000 and 390,000 tons).
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    Sobre la dinámica poblacional de la caballa en la pesquería de Mar del Plata. Período 1980-1990
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero, 1993) Perrotta, R.G.; Pertierra, J.P.
    This species is a principal basic product of the local canned industry. The results show that the biomass and capture were variable for the studied period as a consequence of change in the capturability, and the fishstock is underexploited. Also was estimated the contribution of recruitment, growth and mortality in the total biomass.