Now showing 1 - 5 of 7
- ItemObservaciones sobre diferencias morfólogicas entre la merluza común (Merluccius hubbsi)y la merluza austral (Merluccius polylepis)(Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1980) Cotrina, C.P.; Cousseau, M.B.The species of the Genus Merluccius present in argentine waters, Merluccius hubbsi and M.polylepis are similar externally and it is very difficult to separate them in the capture. Knowing the importance of both species from the commercial point of view, and the need of a correct identification, some morphological characteristics have been compared, looking for external differences, useful for the identification on board. The samples have been taken from the total area of distribution of both species in argentine waters. A total of 154 specimen of Merluccius hubbsi and 105 of M.polylepis were analyzed.
- ItemFertilidad y periodicidad del desove en Ostrea puelchana(Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1980) Morriconi, E.; Calvo, J.Larvae production by Ostrea puelchana was studied in colections obtained from November to March 1977-78 and 1978-79. During the first period there seems to be a direct relation between the highest percentage of gravid female and the moon crescent quarter. This relation is not repeated in the following year. Compared with other larviparous oysters, O.puelchana produces a greather number of embryons of smaller size, with shorter breeding period and longer planktonic life.
- ItemDistribución, áreas de concentración y estructura de la población del bacalao austral (Salilota australis, Gunther 1887) del Atlántico Sudoccidental(Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1980) Perez Comas, J.A.The 'bacalao austral' is a typical fish from the cold water of the Southwest Atlantic and the Southeastern Pacific oceans, whose fishery has not yet developed. In this work, the structure of the concentration areas of summer and winter distribution and other biological items were analyzed, basing on data provening from R/V 'Walther Herwig' and R/V 'Shinkai Maru', which operated in these waters during 1978/79/. The trophic vertical migrations are common in this species.
- ItemLos recursos pesqueros demersales del Mar Argentino. Parte I. Evaluación de la biomasa (Standing stock) de la merluza común (Merluccius hubbsi) y de la merluza austral (Merluccius polylepis) en el área de su distribución estival(Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1980) Simonazzi, M.A.; Otero, H.O.The present paper deals with the standing stock (Pw1) of the common hake (Merluccius hubbsi) and the austral hake (Merluccius polylepis), using the swept are method (Alverson, 1971) and with the Potential Yield (Cmax) using the Gulland (1970)method. The standing stock of the common hake was 2.642.715 tons. the highest concentrations of this specie were distributed over 12.348 nm² (13 o/o of the toal distribution area) with 1.178.843 tons. This area was located between 41° and 45° of south latitude and between the coast and 100 m of bottom depth in the Patagonian Shelf. The other 1.463.872 tons were distributed over a wide area of 82.727 nm².
- ItemReproducción y fecundidad del surel (Trachurus picturatus australis)(Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 1980) Cassia, M.C.; de Ciechomski, J.D.Studies on the sexual maturation on the jack mackerel in the area close to Mar del Plata were carried out throughout the whole year, 56 almost ripe females between 160 and 210 mm in total length and between 38 and 78 g is weight were taken into consideration for fecundity determinations. The most important results obtained during these studies are the following: The gonad index was rather high and reached the value of 11.5. The reproduction season is a rather one and the spawning occurs mainly in December and January. It is assumed that a female of this species spawns once over a reproduction season, but shedding numerous batches of eggs in short intervals. The lowest value found for the fecundity was 15.825 ovocites and the highest one was 82.892. It is started that there exist great differences in the fecundity between the females within the same size and weight groups.