Implicaciones de Ctenopharyngodon idella en la comunidad de peces del río Lacanjá, Chiapas

Abstract

The fish community in the Lancaja river was sampled to assess the relative abundance of grass carp Ctenopharyngodon idella. Five differnt sites were carried out between March and May 1997. A total of 1450 specimens were collected representing 37 species and 15 families; Cichlidae was the dominant family with 15 species. Similarity analysis suggested two different fish assembages separated by a 15 m cascade. The first assemblage ocurred in the lower section of the river; diversity and evenness were highest here. 18 out of 37 species were exclusive to this group. The second assemblage ocurred in the middle section, 16 species were collected there, but none was exclusive. Brycon guatemalensis were captured in both assemblages and C. Idella were captured only in the lower section. Through snorkeling observations B. guatemalensis was the dominant numerically but in biomass C. idella was more important. Neither eggs or juveniles of C. idella were registered.