Host-dependent variation in density of corallivorous snails (Coralliophila spp.) at Curaçao, southern Caribbean.
Snails of the genus Coralliophila (Muricidae: Coralliophilinae) are common in the Caribbean as corallivores that feed on a large range of host species. The present study concerns the distribution of two Coralliophila snails, C. caribaeaand C. galea, at 5-m and 10-m depths at Curaçao (southern Caribbean), as associates of the common scleractinians Orbicella annularis and Pseudodiploria strigosa. Coralliophila galea was abundant on both host species, while C. caribaea was represented only by a single individual on a colony of P. strigosa. No significant differences in shell length were found between snails associated with O. annularis and P. strigosa. The distribution of C. galea on both host species deviated significantly from a random distribution. The snails were most abundant at 5-m depth, particularly on larger colonies of O. annularis, with > 60 % of large colonies colonized by snails, while snails were absent on small colonies. This distinction was not significant in P. strigosa at the same depth or in O. annularis at a depth of 10 m. The results suggest that host preference should be considered in assessments of reef health in connection to damage caused by Coralliophila spp.