Otolith fingerprints of the coral reef fish Stegastes fuscus in southeast Brazil: a useful tool for population and connectivity studies

Otolith fingerprinting is a useful tool in determining the population structure, movement patterns and connectivity among fish habitats. Damselfish, Stegastes fuscus, is a highly abundant reef fish species in the Brazilian coasts. It has been assessed as least concern species according with the IUCN Red List. One hundred and twenty adults, ranging from 85 to 120 mm standard length, were collected in April 2013 by spear fishing in six coastal islands located on Cananéia, Paranaguá, Guaratuba and Babitonga bays, southeast Brazil. Elemental and isotopic signatures of whole sagittae were determined by inductively coupled plasma mass spectrometry and isotope ratio mass spectrometry, respectively. Element:calcium (Sr:Ca, Ba:Ca, Mn:Ca and Mg:Ca) and isotopic ratios (δ18O and δ13C) were analyzed with univariate and multivariate statistics to determine whether these fingerprints can be used to assess the degree of separation between the individuals of these geographic locations. Whole otolith fingerprints representative of the fish entire life-history gave distinct small scale spatial signatures confirming that S. fuscus is a sedentary reef species. Classification accuracy rate obtained from quadratic discriminant function analysis of whole otolith chemistry data was relatively high (71% of mean accuracy percentage). Furthermore canonical analysis of principal coordinates from otolith signatures showed the existence of three regional groups probably a consequence of the similarity of the major estuarine systems that characterize the environment of the nearby coastal islands where fish were collected. This study suggests that otoliths can be used to study the population structure and assess connectivity of the damselfish, providing new knowledge to adequately manage this species.