6 resultados para Bouterwek, Friedrich, 1766-1828
em Aquatic Commons
Resumo:
Western Atlantic synodontid species were studied as part of an ongoing effort to reanalyze Caribbean shorefish diversity. A neighbor-joining tree constructed from cytochrome c oxidase I (COI) data revealed 2 highly divergent genetic lineages within both Synodus intermedius (Agassiz, 1829) (Sand Diver) and S. foetens (Linnaeus, 1766) (Inshore Lizardfish). A new species, Synodus macrostigmus, is described for one of the S. intermedius lineages. Synodus macrostigmus and S. intermedius differ in number of lateral-line scales, caudal pigmentation, size of the scapular blotch, and shape of the anterior-nostril flap. Synodus macrostigmus and S. intermedius have overlapping geographic and depth distributions, but S. macrostigmus generally inhabits deeper water (>28 m) than does S. intermedius and is known only from coastal waters of the southeastern United States and the Gulf of Mexico, in contrast to those areas and the Caribbean for S. intermedius. Synodus bondi Fowler, 1939, is resurrected from the synonymy of S. foetens for one of the S. foetens genetic lineages. The 2 species differ in length and shape of the snout, number of anal-fin rays, and shape of the anterior-nostril flap. Synodus bondi and S. foetens co-occur in the central Caribbean, but S. bondi otherwise has a more southerly distribution than does S. foetens. Redescriptions are provided for S. intermedius, S. foetens, and S. bondi. Neotypes are designated for S. intermedius and S. foetens. A revised key to Synodus species in the western Atlantic is presented.
Resumo:
Age, growth and reproduction of D. russellii were studied. Most of the material used was caught by the commercial fishing fleet, operating in the Sofala Bank (Mozambique) area. A total of 68,000 fish were examined during the period 1979-1981. There were 2 main spawning periods each year, one in February-March and another in August-September. The sex ratio was about 1:1. Ageing was carried out using primary growth rings in the otoliths and analysis of size-frequency distributions. The parameters of the von Bertalanffy's growth equation were determined. Males and females grew at the same rate.
Resumo:
Both in terms of commercial landings and biological importance, the Nile Perch is one of the most prominent fish in Lake Albert. It can bear considerable further exploitation, is the source of stockings elsewhere, and it is, therefore, important to know whether more than one species is being dealt with, and, if so, what differences there are in the ecology of the different species.