Distributions of a Larval Fish Community in a Puerto Rico Reservoir

Information regarding spatial and temporal trends in larval fish distributions gives managers insight into recruitment and ultimately adult population variability. In Puerto Rico, limited research has been conducted on larval fish distributions with no studies addressing reservoir systems. We conducted a study to compare efficacy of two larval sampling gears (larval light traps and bongo-style push nets) and to assess spatial and temporal distributions of larval fish communities in a tropical reservoir. Diversity of catch between push nets and offshore light traps were similar, though species composition of catch was different between gears. Inshore light traps collected greater total numbers and diversities of the larval fish community than offshore traps in spring and summer seasons. Catch per unit effort was greater in the spring for inshore traps whereas CPUE was greater in offshore traps in the fall. Temporal trends indicate Tilapia rendalli and Centrarchidae numbers peak earlier in the summer in littoral habitats, while peak numbers of Ictalurus punctatus increased during autumn in pelagic habitats and were most effectively sampled with light traps. Dorosoma petenense was best sampled with push nets with the greatest catch rates occurring during the spring season. These results will allow managers to coordinate larval fish sampling efforts for specific species with periods of peak abundance and preferred habitat.