THE ECOLOGY OF THE FRESHWATER FISHES OF CENTRAL HONDURAS (NEOTROPICAL, RESERVOIRS, FOOD PARTITIONING, REPRODUCTION)

The objectives of this study were to document fish distribution in the Humuya, Sulaco and Yure drainages of central Honduras, and to investigate the trophic and reproductive ecology of the more common species. Collections were made over a two year period from 22 riverine stations, and from L. Yure, a small, recently constructed headwater impoundment.; A total of 32 species, including 4 exotics, was collected from the area. Species richness within the Yure drainage increased from 6, in a second order headwater stream, to 15, in the fourth order R. Yure near its confluence with the R. Humuya. The cichlids Cichlasoma spilurum and C. motaguense dominated the fish community of the R. Yure, both in terms of numbers and biomass. Two species of pimelodid catfishes were also important components of this assemblage, with Rhamdia quatemalensis increasing and R. cabrerae decreasing in abundance as stream size increased. The characins Astyanax fasciatus and Brycon guatemalensis were most abundant in deeper pools.; Aquatic insect larvae represented the most important food for many of the fish species, but allochthonous material and periphyton were major diet components for a few cichlid, characin and poeciliid species. Diet breadths and overlaps between species were, in general, low within the R. Yure assemblage, and the distribution of diet overlaps exhibited little seasonal variation.; Patterns of reproductive seasonality were diverse, and peak spawning within at least two congeneric species pairs in the R. Yure was staggered through time.; Five species dominated the fish community of L. Yure. During the course of the study, there was a significant increase in the abundance of largemouth bass, and the catfish characteristic of small streams, R. cabrerae, was replaced by a predominantly lowland species, R. guatemalensis. Temporal variation in the diets of these species was documented. Diets were influenced by the increase in invertebrate densities as benthic plant populations developed. Zooplankton were only utilized by fish after the modal plankter size increased following the appearance in the community of Daphnia pulex.; Reproductive seasonality and fecundity of riverine and lacustrine populations of cichlid, characin and pimelodid species were compared. There was some indication of between-population differences in the case of A. fasciatus, but not for the remaining species.