Revista de Investigación y Desarrollo Pesquero 1986 Nro 5

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    Algunas características del florecimiento del fitoplancton en el frente del Río de la Plata. I. Los sistemas nutritivos
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1986) Negri, Rubén M.; Carreto, J.I.; Benavides, Hugo R.
    During the spring (H-04/82: october 11-27, 1982) carried out by the Fishery Research Vessel "Dr.E.Holmberg", the distribution of temperature, salinity, nutrients concentration and photosynthetic pigments were studied at the "Rio de la Plata" maritime front. The presence of Sub-Tropical coastal waters in only station did not allow its characterization. Low Chlorophyll a concentration were noted, in association with scarce concentrations of nutrients and high Margalef index values.
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    Evaluación de la biomasa de adultos desovantes, distribución vertical y variación cuantitativa de la intensidad de los desoves de la anchoíta (Engraulis anchoita) durante la primavera de 1982
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1986) de Ciechomski, J.D.; Sánchez, R.P.; Lasta, C.A.
    Ichthyoplankton was sampled in 9 exploratory cruises in the sea off Buenos Aires province (Argentina), Uruguay and Brazil, during the spawning peak of the anchovy in spring-early summer and mid-autumn. The most abundant speices in the ichthyoplankton was Engraulis anchoita, representing 88. of the eggs and 76. of the larvae collected in all the cruises. These percentages vary boath regionally and seasonally; as regards eggs, the lowest percentage (10% ) was found in January. The distribution of anchovy eggs and larvae, covered almost entirely the surveyed area, with the exception of hte region influenced by the River Plate estuary. Minimum salinity tolerance for the species eggs was 23.5o/oo. The eastern limit of the distribution of anchovy eggs, extends in spring-early summer to the 200 m isobath in the northern part of the study area, whereas in the south rarely extends beyond the 50 m isobath. Anchovy larvae showed a wider distribution, penetrating in November and December in the brackish waters of the Samborombón bay, extending over more off-shore waters in January. As the spawning season progressed a southwards movement of intensive reproduction nuclei was observed. The average daily egg production during spring-early summer was estimated at 260 anchovy eggs/m2/day; in autumn, a ten-fold reduction of this production was observed. On the basis of the seasonal egg production for spring-early summer, calculated at 3.5238 E15 eggs and the larvae census carried out in mid-January a 98.2% mortality during the imbryonic and larval stages of the anchovy could be assumed. The spawning biomass of the anchovy during this period was calculated at 2,514,970 t. Preliminary results on the vertical distribution of anchovy eggs and larvae show that their distribution is generally restricted to the upper 50 m water layer, with higher concentrations at 10 to 25 m depths.
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    Ecología trófica de la anchoíta (Engraulidae, Engraulis anchoita) del Mar Argentino. Parte III. Requerimiento trófico individual en relación con el crecimiento, ciclo sexual y las migraciones estacionales
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1986) Angelescu, Víctor; Anganuzzi, Alejandro
    The paper was developed in order to arrange the data gathered on this subject and to generate new hypotheses in connection with the trophic strategy of the northern stock of anchovy in the area between latitudes 35°-42°S. Such estimates were finally compared with the values of the gravimetric determinations of stomach contents- as converted to caloric values - of individuals grouped by total-length amd age classes, ecological areas, and seasons of the year. The set of results as obtained conforms the initial basis for developing Part IV of the Trophic Ecology of the Argentine anchovy as related to food consumption estimates, by stock biomass and annual classes, with back-calculations to age class 0, and for applying "regional patterns" that result from the "consumer-food" relationship.
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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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    Estudios de distribución de la anchoíta (Engraulis anchoita) en un área de extensión reducida. I. Densidades mínimas de muestreo para la estimación de algunos parámetros poblacionales
    (Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1986) Gru, D.L.; Hansen, J.E.
    Results of a research cruise carried out to estimate some biological parameters of anchovy (Engraulis anchoita), during the major spawning season, were analyzed in order to determine the minimum number of samples required to obtain unbiased values. Twelve samples of fishes were taken within an area of 607 nm². Size (total length)distributions, slope of the length-weight relationship, sex ratio and age population structure were considered. Results suggest that those parameters should be estimated by eight or more samples (corresponding to 76 nm² each).