Genetic diversity of three ornamental reef fishes (Families Pomacanthidae and Chaetodontidae) from the Brazilian coast

Abstract

Reef fishes of the families Pomacanthidae (angelfish) and Chaetodontidae (butterflyfish) are popular ornamental species, intensively harvested for the aquarium trade. The impacts of such activity on intra-specific diversity and reef ecosystems are still poorly understood in the south Atlantic. In the present work, a fine-scale genetic analysis using RAPD markers was performed in distinct samples of the queen angelfish (Holacanthus ciliaris), French angelfish (Pomacanthus paru), and banded butterflyfish (Chaetodon striatus) along the Brazilian coast. Most of the genetic variation in the three species was related to intra-population diversity. However, AMOVA results demonstrated that H. ciliaris presents a subtle population structure (φst = 0.132, P = 0.003), while P. paru and C. striatus present low genetic differentiation, especially remarkable in the latter (φst = 0.090, P = 0.001 and φst = 0.041, P = 0.028, respectively). Gene flow (Nm) was also higher in C. striatus than in the angelfish species. The reported patterns of genetic differentiation contrast with the similar pelagic stage of the selected species, suggesting that larval dispersal per se is a poor predictor of population structure in these reef fishes. Ecological features coupled with biogeographic history and distinct local selective pressures might play a major role on the genetic composition of each species. Although preliminary, the present results provide a baseline for monitoring the genetic variability in these reef species. These differences in the genetic structure among co-occurring species should be taken into consideration for the conservation of eventual evolutionary units along the Brazilian Province.