Abstract
This study concerns the reproduction of Austrolebias nigrofasciatus, an endangered annual fish species endemic to the waters of the Sao Goncalo channel and its tributaries in southern Brazil. Three breeding pairs confined in small cages for four weeks in their biotope were observed to produce an average of 21.5 plus or minus 12.0 eggs/week/female, with a range of 3-39 eggs/female/week. Average egg diameter was 1.51 plus or minus 0.12 mm, with abrupt changes observed throughout the period of study. The mean oviposition observed was within the range found for other killifishes and demonstrates the high fecundity rate of the species even under confinement conditions.
Highlights
Studies have shown that killifishes have elaborate reproductive behavior, mainly associated with the marked sexual dimorphism of the species
Little is known about their reproduction in their natural environment (Arenzon et al 1999; Shibatta 2005)
Egg size influences the fitness of mothers and offspring (Bernardo 1996), being an important determinants of egg and larval quality that is positively correlated with egg and fry survival and larval growth rate (Gall 1975; Chambers 1997)
Summary
Studies have shown that killifishes have elaborate reproductive behavior, mainly associated with the marked sexual dimorphism of the species Austrolebias is the second most representative genus of annual fishes, with 34 recorded species (Costa 2008). Regarding the possible strategies for ensuring Rivulidae conservation, several authors stress the importance of conducting studies aimed to improve the knowledge on the biology and ecology of these species (Reis et al 2003; Rosa & Lima 2008; Volcan et al 2010).
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