摘要:

The Atlantic eels,Anguilla anguillaandA. rostrata, have partially overlapping spawning sites and show incomplete reproductive isolation as testified by the presence of hybrids at low frequency. Nevertheless, significant genetic differences between the two species have been pointed out by data on biochemical polymorphisms and mitochondrial DNA. This study reviews the cyto‐genetic and molecular data and points out differences and similarities between the two species.

ISSN:1125-0003    

DOI:10.1080/11250009809386797

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Sound systematic data are important for conservation. Without accurate taxonomy, it is impossible to identify the species and evaluate their conservation status, it is impossible to properly manage their fisheries, it is impossible to evaluate the conservation value of habitats or areas, it is impossible to establish strategies and it is impossible to set priorities. Despite having been the object of research for more than 450 years (double than the fauna of any other continent), the systematics and nomenclature of European freshwater fishes is still chaotic. Poor practices, poor theoretical concepts, absence of international communications and nationalism are responsible for the poor quality of systematic work. Fish taxonomy should be addressed by trained taxonomists, not by fisheries biologists.

ISSN:1125-0003    

DOI:10.1080/11250009809386798

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

More than half the New Zealand freshwater fish fauna is diadro‐mous, most of these species being amphidromous. Diadromy is a major determinant in many aspects of the historical and ecological biogeography of the fauna. These aspects include: 1) serving as a source of ancient to recent derivations through transoceanic dispersal of diadromous species, a process that continues today; 2) populating remote, oceanic islands in the New Zealand region; 3) maintaining fish populations on nearshore islands with ephemeral streams; 4) determining the overall ranges of species both within and beyond New Zealand; 5) providing a major contribution to species richness in river systems; 6) structuring of riverine fish communities; 7) facilitating recovery of communities after perturbation at recent and geological time scales. Overall, diadromy is seen as the single strongest determinant of the characteristics of the fauna. Principles that account for this contribution by diadromy to the nature of the fauna apply globally, to the extent that fish faunas in other parts of the world are diadromous.

ISSN:1125-0003    

DOI:10.1080/11250009809386799

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Ranges of freshwater fish species depend on river basins. However, most species are confined to a limited area of a basin. Some limited distributions are determined by the ecology of the species, most have historical grounds. Many species are endemic to a restricted area of a river basin (e.g., 7 in the River Danube; more than 80 in the Mississippi river basin). Most non‐endemics confined to a sector of a river basin also live in one or more adjacent basins. Cases are known of conspecific subspecies inhabiting distinct areas within a river basin, some of them being also present in a neighbouring basin. Restricted distributions are determined by the fact that river captures usually involve tributaries, not the main rivers and the inhabitants of the upper and middle reaches of the river do not disperse through the lower reaches.

ISSN:1125-0003    

DOI:10.1080/11250009809386800

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The last decade has seen a considerable increase in the amount of ichthyofaunistic studies throughout the countries of the Eastern Mediterranean. As a result, we now have a more accurate picture of the distribution of Red Sea fishes (Lessepsian migrants) in the region. A clear gradient emerges, with 54 substantiated records on the Israeli‐Lebanese coast. The gradient decreases along the northern and southern coast of the eastern Mediterranean, as distribution spreads westward. Only four Lessepsian fish species have been found in the central region and, to date, none in the western basin. These 54 species represent 36 families, of which 13 are new to the Mediterranean. The primary factors limiting distribution are the presence of an adequate continental shelf, which is the habitat most prone to Lessepsian colonization, and the temperature regime. Cooler temperatures constitute a physiological constraint to fish of tropical origin. A biological survey of the Lessepsian fishes along the coast of Israel indicates that those species whose spawning seasons commence in early (i.e. cooler) months are more likelytobe successful in spreading westward.

ISSN:1125-0003    

DOI:10.1080/11250009809386801

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The freshwater fishes of Iran comprise 155 species in 24 families, the most diverse family being the Cyprinidae with 74 species. Nineteen families have 5 or fewer species. Endemics number 24 species although this is expected to increase as new species are described. More than two‐thirds of the species are restricted to a single drainage basin out of 20 examined although two cyprinid species are reported from 10 or more basins. The Caspian and Tigris basins have the most species with 74 and 54 species respectively. Iran compares favourably with neighbouring countries in its diversity. At least 27 exotic and transplanted species have been reported from Iran although not all are established. The most widespread species is the exotic mosquitofish.

ISSN:1125-0003    

DOI:10.1080/11250009809386802

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

About 31 species in eight genera and two families (Nemacheilidae and Cobitidae) are reported from Iran and adjacent countries (i.e., Iraq, Turkey, Afghanistan, and Pakistan). Six new species, five from Iran and one from Afghanistan, are described. Several Iranian loach genera are also found in western Palearctic region (i.e.,Sabanejewia, Cobitis, andOrthrias), or eastern Asia (i.e.,Schistura).But other genera such asParacobitisandSeminemacbeilusare endemic to, or exclusive of, Middle Asia. Our investigation confirms the important role of Iranian drainages as a biogeographic bridge between western‐Palearctic and Oriental fish faunas.

ISSN:1125-0003    

DOI:10.1080/11250009809386803

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The subfamily Barbinae from southern Europe includes 17 fish species: 8 in the genusBarbuss.str. and nine in the new genusMessinobarbus.According to their recurrent, preferential habitat European barbs can be divided in three groups: a) large‐sized, warm‐water adapted species (i.e., “bocagei‐barbus”;group) composed of eleven species; b) medium‐sized, moderately cold‐water adapted (i.e., “meridionalis”;group) comprised of four allopatric species; und c) medium‐sized, warm‐water adapted, moderately riverine or lacustrine species (i.e.,"cyclolepis”;group) with two species. Major Barbinae diversity occurs on the Iberian Peninsula with eight species and in Greece with five species. Riverine species tend to form paired complexs: each generally consisting of a lacustrine and a moderately riverine form in each basin. The. current ecological segregation or allopatry between riverine species suggests that they were derived from precocial (pedoge‐netic) populations of a lacustrine (especially those from the Up‐per‐Aegen Sea) Barbinae species during sequential waves of colonisation that occurred during glacial melting periods throughout the Pleistocene. The progressive reduction of a dorsal fin spine may coincide with the vicariant formation of these species. Species which display well developed horny tubercles on the snout are included in a new genus,Messinibarbus, comprised of nine endemic species (seven on Iberian Peninsula and two in western Greece). A new species,Messinobarbus carottae, previously misidentified asB. graecus, is described from Lake Yliki in Beothia, Greece.

ISSN:1125-0003    

DOI:10.1080/11250009809386804

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In the Ziemenbach, a third order stream of the Peene system, the habitats and density of brook lamprey(Lampetra planert) were investigated. A catalogue of habitat requirements for ammo‐coetes and adults was compiled. The abundance of brook lamprey was determined by counting adults on the spawning sites and systematic sieving of the ammocoetes. Human impact is probably the reason for strong changes in the population density during the investigated years. Habitats of lampreys in European streams are endangered by channelling and river maintenance. Together with other factors, this has led to the extinction of many populations. The occurrence ofL. planenin the Peene drainage is now limited to 15 tributaries, although suitable habitats have been found in 36 streams, one third of the whole drainage system. To reduce the isolation of the populations and to enable the resettlement in other streams, up to 70 weirs with fish passes have to be construct.

ISSN:1125-0003    

DOI:10.1080/11250009809386805

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Fishes of the genusPoeciliaare predominant inhabitants of the Central American mainland and of the Greater Antilles. The genus also occupies specific habitats on the South American continent and adjacent islands. In Central America, there is a confusing array of species, in which morphological and meristic characters show more variation within species than between species. By applying the principle of character displacement to the genus, several regularities emerge. Three species pairs (of which one has uni‐cuspid inner jaw teeth, the other has tricuspid inner teeth for each species pair) are present, amongst which six widely dispersed species may be discriminated. A species concept based on phylogenetic and taxonomic methods is defined for the genusPoecilia.The application of a peculiar mode of character displacement to two species of fish from El Salvador suggests a general mechanism that explains much of the morphological variation within the Central American members ofPoecilia.This method also defines species boundaries and patterns of speciation based on ecologically derived mechanisms.

ISSN:1125-0003    

DOI:10.1080/11250009809386806

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor