Composition and structure of the ichthyofauna in the Hondo River, Mexico-Belize, using a harpoon

Abstract

Composition and structure of the Hondo River ichthyofauna and its spatial variation were determined as afunction of environmental parameters. Six sites along the river were sampled in March, April and May 2012. Data forestimating structure of fish assemblages was obtained by means of a 58.5 cm harpoon during 2 hours of free diving ateach sampling site. The species list for the study area was completed with the aid of gillnets, longlines, double-conetraps, and hook-and-line. In addition, a bibliographical research performed as well as the ichthyological collection ofECOSUR at Chetumal was checked. The systematic list includes 40 species in 33 genera, 18 families and 11 orders.The richest family was Cichlidae, including the exotic Oreochromis niloticus. The environmental parameters that bestdescribed distribution and abundance of fish in the Hondo River were river width, distance to mouth, transparency,depth, dissolved oxygen concentration, and conductivity. Correlation between species and environmental parameterswas high in both axis (0.89 and 0.79). The river was classified into 3 environmental zones, although its fish faunacould be divided in 2 main assemblages.