Community Structure of the Demersal Fish Species of Laguna Joyuda, Puerto Rico

Abstract

A year-long trawl survey of the mangrove-fringed Laguna Joyuda, Puerto Rico yielded 41 species of juvenile and adult fishes. Twelve percent of the species and 55% of the individuals were residents in the lagoon; 56% of the species and 44% of the individuals were cyclic visitors, mostly juveniles of species which spawn offshore. The lagoon yielded fewer species than tropical estuaries in continental regions of the Caribbean and temperate estuaries of North America. However, paralleling other estuarine habitats, Laguna Joyuda supported three primary types of fishes, a resident small flatfish (Achirus lineatus), a complex of transient juveniles (Gerreidae, paralleling the Sciaenidae of higher latitudes), and small planktivores (Anchoa spp.). Seasonal patterns in the abundance of individual species were not strong, but overall abundance showed a wet season maximum, particularly because of recruitment of anchovies and cyclic visitors in April, May, and June. Wet season abundance corresponded with highest water column productivity and detrital input to the benthos. Fishes associated with the water column appeared to show greater variation in abundance than those associated with more stable benthic food webs.