A survey of cardinalfish (Apogonidae) of Antsiranana Bay, northern Madagascar

Abstract

The cardinalfish of Antsiranana Bay, northern Madagascar, were surveyed over an 11 month period by underwater census employing a simple search pattern using self-contained underwater breathing apparatus. Over this period 15 species were observed including one species not previously recorded in Madagascar, Siphamia versicolor. Whilst some species were ubiquitous across sites within the bay others appeared only as single records. Cardinalfish communities were compared between sites within the bay using PRIMER 6 (Plymouth Routines In Multivariate Ecological Research) and on a national scale against existing records. Overall the species richness of cardinalfish in Antsiranana Bay is less than that observed in other regions of Madagascar. The reasons behind these regional variations include oceanic currents, temperature, depth, disturbance and sedimentation, a recognised threat to Madagascar’s marine communities. This final point was reaffirmed by comparison of cardinalfish communities between sites within the bay which revealed little variation in species composition between sites, with the exception of highly-sedimented sites in the north - east of the bay that had a significantly different cardinalfish fauna to the rest. As a family that rely on the complexity of the coral reef for shelter, and exhibit high site fidelity, examination of cardinalfish communities may provide a measure of the health of a region’s reef.