EXTRAIT: Origine des pouss~es ovocytaires chez Tilapia mossambica. L'ovaire de TiIapia mossambica a ~t~ ~tudi~ dans le but de pr~ciser l'origine des pouss~es ovocytaires. Apr~s la ponte l'ovaire n'est pas vide pour autant, et il y subsiste des ovocytes ~t tousles stades du d~veloppement. Les replis de l'~pith~Iium germinatif et les tractus ~pith~liaux ramifies contiennent des flots de cellules qui produisent des ovogonies primaires, lesquelles se transforment en ovocytes et en cellules folliculaires. I1 ne semble pas qu'une nouvelle pouss4e ovocytaire puisse se faire ~ partir des r4sidus des follicules des ovocytes atr~tiques. Seuls les ovules m6rs non ~vacu~s par la ponte subissent une atr~sle et se rdsorbent; les ovocytes immatures ou en vole de croissance ne d~g~n~rent pas. L'asynchronisme de T. mossambica se traduir par la pr& sence simultan~e, dans l'ovaire, d'ovocytes ~ tousles stades de croissance et de maturation.
A population of the S. Indian cyprinid fish Barbus melanampyx was sampled monthly through 24 months. Seasonal cycles of the gonado-somatic index (GSI), ovarian stages, male breeding tubercles, spawning behaviour and population structure were assessed. These fish breed strictly seasonally during the main dry period: December/January through April. Comparison with other Barbus species of the same general region led to the conclusion that the patterns of reproductive investment of B. melanampyx are similar to those of perennial species, and different from those of wet-season spawners. The reasons for this rather unexpected result were found in the more constant conditions prevailing during a dry season as compared to the monsoon. It was argued that B. melanampyx and the species spawning perennially are in effect 'small-brood' spawners, rather than partial spawners.
The formation of the micropyle in Tilapia mossambica and Stigmatogobius javanicus, two fresh water teleosts is described. In T. mossambica the micropyle is formed by a single modified follicular cell, while in S. javanicus it is formed by a cellular mass derived from the follicle.
The length-weight relationship of P.amphibius was calcu lated separately for males and females. Results reveal that there is a close relationship between the length and weight of the fish. The regression coefficient of males was significant at 1 % leveL By testing the regression coefficients against the isometric value of 3, it was found that for females the growth pattern agrees with the isometric growth formula while in the case of the males the cubic formula was not found to be a proper representation of the length weight relationship.
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