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  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 32 (1988), S. 0 
    ISSN: 1095-8649
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: The spawning season of chub, Leuciscus cephalus, in western Greece starts in January-February when males are aged at least 2 + and females 3 + (rarely 2 +) years. In the R. Ermitsa (Achelos R. basin) a population is reported with fingerling adult males with developed gonads and breeding tubercles at a size of 42 72 mm s.l. Leuciscus pleurobipunctatus breeds between February and the first half of May, when males are aged at least 1 + and females 2 + (sometimes also 1 +); their life span is about 4 years. L. cephalus × L. pleurobipunctatus hybrids were found in the R. Ermitsa (five specimens) and R. Louros (one specimen). In the former the contemporary presence of adult fingerling male chub, the smallest adults of L. pleurobipunctatus, and hybrids between the two species, may be related to channel width and the human interference which has resulted in considerable disturbance of the habitat.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 21 (1982), S. 0 
    ISSN: 1095-8649
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Thirty-six specimens of hybrid between the cyprinid species Alburnus albidus and Leuciscus cephalus cabeda were recognized from samples collected from five rivers in southern Italy. In the Alento river hybridization was marked and in a single sample of 66 specimens, 23 were found to be hybrids. The identification of hybrids is easy due to the combination of intermediate characters such as body pigmentation, gill rakers, branched rays of anal and pelvic fins, and some proportional measurements. The growth rate of hybrids is intermediate between the parental forms. Males are more numerous than females.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 37 (1990), S. 0 
    ISSN: 1095-8649
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 32 (1988), S. 0 
    ISSN: 1095-8649
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 59 (2001), S. 0 
    ISSN: 1095-8649
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: In a survey of the west-central Italian rivers Ombrone, Fiora, Albegna and Bruna, among established exotic species, the Iberian barbel Barbus graellsti was recorded in Italian fresh waters for the first time. Morphological identification was supported by comparison of cytochrome b sequences with those from related barbel species. Other exotics of particular note were Barbus barbus, Pseudorasbora parva and Leuciscus cephalus, together with the Padano-Venetian Chondrostoma genei and Padogobius bonelli. Native species still present included Leuciscus lucumonis, Telestes muticellus, Rutilus rubilio and Padogobius nigricans, but were now more restricted to upper reaches and smaller watercourses. The deleterious effect of alien species on native forms is discussed with particular reference to probable competition between C. genei and L. lucumonis, and between the two gobies. The checklist of species introduced to the fresh waters of Italy is now updated to 34. For the Italian freshwater fish fauna in general, the conservation status of three native species (Acipenser naccari, Salmo marmoratus and Knipowitschia punctatissima) has been improved but five species are believed to be at risk (Salmo carpio, L. lucumonis, Scardinius scardafa, Gobio benacensis and P. nigricans) and four anadromous species (Petromyzon marinus, Lampetra fluviatilis, Acipenser sturio and Huso huso) no longer breed in Italian fresh waters. The processes of change in the composition of the Italian freshwater fish fauna as a whole may be summarized as successively ‘padanization’, ‘danubization’ and now ‘globalization’.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 31 (1987), S. 0 
    ISSN: 1095-8649
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: The freshwater fish fauna of Greece is a diverse assemblage of mediterranean, Ponto-Caspian, and endemic western Greek elements. In the last category, a gobiid from Epirus has been found to possess a dermal perianal organ unique among teleosts, as well as systematic features warranting recognition of a new genus, Economidichthys gen. nov. (type-species Gobius pygmaeus Holly, 1929). The perianal organ is a sharply-demarcated, pitted area on the rear abdomen. Light-and electron-microscopy has revealed numerous specialized microvillous cells lining the pits and evidently secretory in function. Presence of the organ in both sexes, its ventral position and the secretory activity originally suggested an attachment role rather than involvement in reproduction, but obvious correlation with habitat is lacking and alternative functions are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    ISSN: 1439-0426
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: We examine the evolving concept of what constitutes a non-native (or alien) freshwater fish. In an attempt to distinguish between biogeographical and socio-political perspectives, we review the patterns in the introduction and dispersal of non-native fishes in Europe and North America, and especially the recent expansion of Ponto-Caspian gobies in Europe. We assess patterns in the development of national policy and legislation in response to the perceived threat of non-native fish introductions to native species and ecosystems. We review, and provide a glossary of, the terms and definitions associated with non-native species. Finally, we discuss perspectives as regards the future treatment of naturalized species.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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