Revista de Investigación y Desarrollo Pesquero 1986 Nro 5

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Browsing Revista de Investigación y Desarrollo Pesquero 1986 Nro 5 by Subject "Anchoíta"

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    Distribución del plancton a mesoescala en un área de reproducción de la anchoíta en la plataforma bonaerense
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1986) Akselman, Rut; Carreto, J.I.; Ramirez, F.C.
    In order to determine the distribution patterns of phytoplanktonic and zooplanktonic species that constitute the main food of the argentine anchovy (Engraulis anchoita), a study was made within a coastal spawning area on meso-scaled space (approximately 7 miles between stations). It was observed the predominacne of the copepod Oithona helgolandica and copepodites stages of other small-sized species, thus inferring the preponderance of nauplii stages which constitute the main food of early anchovy larvae. A high spatial heterogeneity was found in the distrtibution of both phytoplanktonic and zooplanktonic communities. Phytoplankton showed a patchiness distribution both in horizontal and vertical directions. Diatoms, dinoflagellates and coccolithophoirids showed their own distribution patterns with biomass nuclei centered at different stations. The spatial distribution of the components within each taxonomic group seems to be of the contagious-type distribution. The positive correlation (r= 0,64*) as observed between immature stages of copepods and coccolithophorids seems to indicate a trophic direction of these consumers, which is also supported by the finding of coccolithophorids in copepods pellets. The phytoplankton crop as measured by population census and chlorophyll a concentrations (0,0-0,91 mg/m3) indicates an area of a low productive capacity.
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    Estudio comparativo de caracteres merísticos y morfométricos de la anchoíta (Engraulis anchoita)
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1986) Ratti, M.M.
    The argentine anchovy (E.anchoita) shows a distributional area between 35° and 47°30' on the continental shelf off Argentina. This paper deals with some meristic and morphometric characters in order to test their power in separating different stocks. Those largely scattered distributions of morphologic features, which had been already pointed out other authors, make difficult to separate different stocks of this species on this basis.
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    Estudio sobre el crecimiento en peso y factor de condición en larvas de anchoíta, Engraulis anchoita Hubbs & Marini. Variaciones regionales, estacionales y anuales
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1986) de Ciechomski, J.D.; Sánchez, R.P.; Alespeiti, Gabriel; Regidor, H.
    The equation log W=a+bL (where W=dry weight in ug, and L=total length in mm)was used to describe the growth in weight of larval anchovy collected in two areas of the Argentine sea, sampled in different months and several years. Regression lines were compared by covariance analysis applied to two size groups, namely larvae less and over 10 mm total length, as an evident break in the slopes indicated the existence of a chenge of rythm in the trajectory of larval growth in length. Significant differences between the slopes of the growth lines were observed within the smaller size group. No regional or yearly differences could be established fo larvae larger than 10 mm.