Spatial distribution of cichlids in Tzendales River, Biosphere Reserve Montes Azules, Chiapas, Mexico

Abstract

Located within Mexico’s Montes Azules Biosphere Reserve, the Tzendales River is part of the Usumacinta River Basin, which supports the largest diversity of cichlid fishes in Middle America. We evaluated temporal and spatial variation of species richness and distribution of cichlids in the Tzendales River; we collected 14 species with nine native and five endemic. The species with greatest relative abundances and broadest spatial distributions were Vieja intermedia and Amphilophus nourissati; and the rarest and most spatially restricted species were Thorichthys meeki and Parachromis friedrichsthalii. Environmental characteristics varied seasonally although fish assemblages and distributions were relatively stable over time. Based on habitat use patterns, three species associations were observed: (1) Amphilophus nourissati, Petenia splendida, Vieja argentea, V. bifasciata, V. intermedia, V. pearsei, V. synspila and V. ufermanni; (2) ‘Cichlasoma’ salvini and Parachromis friedrichsthalii; and (3) Thorichthys helleri and Thorichthys meeki. Two rheophilic species, Theraps lentiginosus and Theraps irregularis, had low habitat overlap with all of the other cichlid species. Canonical correspondence analysis showed that the depth, current speed and quantity of rocks in the substrate defined the spatial distribution of species in dry season. Cichlids of the Tzendales River appear to partition habitat in a manner that reduces resource competition.