A comparison of two visual census methods of coral reef fishes in the Bahía de Murdeira, Sal Island, Cabo Verde

Abstract

This study aims to compare the efficiency of two underwater visual census methods on tropical fish communities of Murdeira bay, off the southwestern coast of Sal Island, Cabo Verde. Two methods were tested: strip belt transect and stationary point count. Parameters compared were: species richness, abundance and diversity (d’). The results show that there are significant differences due to the interaction between the method and location, being site 2 the one that showed significant differences in the estimates generated by each method. The analysis of species sampled performed for the entire experiment shows that the stationary point count method is the most complete, as it is able to record more species and individuals than the transect method. Finally, the diversity analysis reveals that site 2 is the most diverse, coinciding with the only location where differences in the estimates were found according to the sampling method used. This study highlight the advantages of using non-destructive methods and the importance of taking into account the characteristics of the study area for choosing the sampling method.