BIOLOGIA REPRODUTIVA E DINÂMICA POPULACIONAL DE Hypancistrus zebra ...

  • "BIOLOGIA REPRODUTIVA E DINÂMICA POPULACIONAL DE Hypancistrus zebra ISBRÜCKER & NIJSSEN, 1991 (SILURIFORMES, LORICARIIDAE), NO RIO XINGU, AMAZÔNIA BRASILEIRA"


    ANA PAULA OLIVEIRA ROMAN


    Abstract


    Hypancistrus zebra is a specie used with ornamental purposes, endemic and rare in the Middle - Lower Rio Xingu, which has strong demand from the international ornamental fish market, which created a strong pressure of exploitation associated with this species. H.zebra is included on the list of Brazilian fauna threatened with extinction and their capture is prohibited. It is known that even prohibited, it continues to be captured and exported illegally, together with the construction of this hydroelectric Belo Monte in his patch of distribution, which threatens their geographical distribution and lack of information on its biology and ecology make it difficult planning actions for this species. So, if this work aimed to study aspects of reproductive biology and population dynamics to contribute to conservation measures for this species. Specimens of H. zebra were taken monthly from March 2009 to February 2010, by diving with a compressor, on the Xingu River, between the location of the weevil and Rita village of Belo Monte. The captured individuals were weighed and measured (total weight and total length). The gonads were removed and immediately fixed in Bouin solution. This was followed by routine histological techniques and the slides were stained with hematoxylin-eosin (HE). The stages of gonadal maturation were described based on the presence of germ cells at different stages of development. Through the length frequency data, estimates of population parameters such as growth models, recruitment, mortality, yield per recruit and size of first gonadal maturity. The species showed a seasonal spawning peaks between the two transition seasons of drought and flood (and vice versa) of the river, and two periods of recruitment, with different growth rates. It was estimated that the species has a lifespan of five years, and is at the limit of maximum sustainable yield, which is characterized as a dangerous situation for the species, because any increase in effort will compromise the stock and it is not known impacts that occur as a result of changes in their habitat caused by dam construction.
    Quelle: "UNIVERSIDADE FEDERAL DO PARÁ INSTITUTO DE CIÊNCIAS BIOLÓGICAS PROGRAMA DE PÓS-GRADUAÇÃO EM ECOLOGIA AQUÁTICA E PESCA" (in Portugisisch)


    Viel Spaß beim Lesen
    Elko

  • SERVER NICHT GEFUNDEN :whistling:


    Interessant, dass die durchschnittliche Lebenserwartung im natürlichen Habitat mit nur 5 Jahren angegeben wird :huh: können sie doch in "Gefangenschaft" nachweislich mindestens 20 Jahre alt werden!
    Meine nach wie vor (relativ) fröhlich züchtende Wildfanggruppe würde es also im Rio Xingu mittlerweile wohl schon gar nicht mehr geben..... :( wären sie nicht zwischenzeitlich mal bei mir untergekommen :)
    Jetzt ärgert es mich auch nur noch halb so sehr, dass alle heiligen Zeiten mal einer der großen Tiere abschmiert ;( ist eben der Lauf der Dinge und wenn die bei ihnen zu Hause im Schnitt eh nur 5 Jahre alt werden, dann sind meine WF allesamt schon steinalte Greise :S


    Gruß
    Stefan

  • Hallo, Stefan ! Gruß aus dem herbstlichen Münsterland..... Frage: Wie groß sind denn deine großen L 46 ???
    Bitte kurze Info, Danke ! Ansonsten wünsche ich dir ein schönes Wochenende- Claus.

    Ein mongolisches Sprichwort: Berge können sich nicht miteinander unterhalten, aber MENSCHEN ! ;)[bestand]1869[/bestand]

  • Hallo, Stefan ! Meine WF haben so ca. 4-5 cm, sollen angeblich bis 10 cm erreichen ! Habe ich in
    der Größe aber auch noch nicht gesehen- Claus.

    Ein mongolisches Sprichwort: Berge können sich nicht miteinander unterhalten, aber MENSCHEN ! ;)[bestand]1869[/bestand]