The spawning season of the Caribbean spiny lobster Panulirus argus (Latreille) was identified based on adult specimens collected monthly off northeastern Brazil, from August 1982 to July 1988. The maturity indices used were relative abundance of females with full spermatheca, eggs or rests of spermatheca, female gonad weight and relative abundance of stage four females. The main spawning activity occurs in February to May, with an occasional second peak in September/October.
Vital statistics are presented for 38 marine species of Vanuatu based on previous studies conducted in the area, with parameters describing growth (6 species, 13 sets of parameters), mortality (estimates of M for 6 species), length-weight relationship (32 species), and reproduction (length at first maturity for 26 species, months of reproduction for 18 species). The species covered belong mainly to the family Lutjanidae.
A cheap method of propagating the African catfish, Clarias gariepinus, by incubating the fertilized eggs in a cage placed directly in a flowing river is described. Hatching ranged between 39 and 70%. This is not significantly different from the commonly used water recirculating flow through system. The economic advantages of the river hatching method are discussed with special emphasis on the rural fish farmers.
We studied the reproductive and trophic ecology of a group of aquatic and semi-aquatic snakes that face severe hunting pressure in Cambodia. Over a two-year period we sampled hunters' catches, measuring and dissecting a total of 8982 specimens of seven snake species, five of which belong to the family Homalopsidae. The seven species—Enhydris enhydris, Enhydris longicauda, Homalopsis buccata, Enhydris bocourti, Erpeton tentaculatus, Xenochrophis piscator, and Cylindrophis ruffus—all inhabit Tonle Sap Lake, the largest lake in South-East Asia.
This study describes the hatchability, growth, sex ratios and reproductive behavior of intergeneric hybrids between Tilapia zillii (Linneus) and Sarotherodon galilaeus (Linneus), and between T. zillii and Oreochromis andersonii (Castelnau), O. aureus (Steidachner), O. macrochir (Boulenger), O. mortimeri (Trewavas), O. mossambicus (Peters), O. niloticus (Linneus), O. placidus (Trewavas), O. spilurus (Gunther) and O.tanganicae (Gunther). Only hybrid crosses using T. zillii as the maternal parent were successful. Mean fertilization rates of the pure T.
This contribution summarizes knowledge on the biology (population dynamics, reproduction, ecology) of 25 fish species from the Lower Amazon, Brazil, based on data from a Brazilian-German field project (IARA) and a review of the literature.
The expected more interest of marine aquaculture projects in Egypt will increase the demands of marine seed production for a variety of species. The limited and inconsistent availability of wild finfish and shellfish larvae together with an urgent need of establishing selective breeding programs increased the interest in captive reproduction of finfish and shellfish worldwide. The selection of a species suitable for Egyptian marine aquaculture depends primarily on its marketing value, biology and the ability to produce juveniles in significant numbers for commercial production.
Between May and October 1990, fecundity, egg size and condition factor of Chrysichthys nigrodigitatus (Lacépède) in the Cross River, Nigeria, were studied. The fecundity (F) of this population varied from 3 046 eggs (total length, L=28.5 cm) to 28 086 eggs (L=64 cm). A mean relative fecundity of 231 eggs/cm or 13 eggs/g of fish was obtained for this population. The fecundity of this population can be estimated with the formula F=2.511 · L 2.30 or F=52.893 · W 0.78 , total length being in cm and weight (W) in g. The mean egg diameter of this population varied from 0.65 mm to 3.54 mm.
The International Center for Living Aquatic Resources Management (ICLARM) in collaboration with the Food and Agriculture Organization of the United Nations (FAO) and with the support of the Commission of the European Communities is developing a database (called FISHBASE) to summarize global information on living aquatic resources (fish, crustaceans and molluscs) in a standardized form to be made available on CD-ROM to institutions in developing countries.
Information on reproduction in reef corals is presented. An understanding of its reproductive behaviour is an important factor in helping to preserve the coral reef ecosystems.