MOLLUSK COMMUNITIES OF TROPICAL RUBBLE SHORES OF CURACAO - LONG-TERM (7(+) YEARS) IMPACTS OF OIL POLLUTION

Mollusc communities of unpolluted and tar polluted rubble shores of in termediate wave-stress in Curacao, were compared, At unpolluted sites, mollusc densities averaged in excess of 1000 snails, limpets and chit ons m(-1) of shorefront, while species richness averaged 20.7 species m(-1) of shorefront. Shores massively soiled with crude oil in the pas t, but which have not been directly impacted by oil spills or signific ant levels of chronic fresh oil pollution since at least 1986, have re tained high concentrations of tar principally in the coarse rubble zon e at mid-shore level. Average mollusc densities (m(-1) of shorefront) at such sites were 20.6% of those encountered at unpolluted sites, whi le mollusc species richness was 63.8% that of unpolluted sites. Mollus c densities and species richness were, respectively, log-linearly and linearly correlated with percent tar cover. Furthermore, the species c omposition of polluted shores was characterized by an increased relati ve abundance of littorinids and tidal bench species to the detriment o f two planaxids, several neritids and other mid-shore species preferri ng the coarse rubble habitat.