Available data on species distributions and endemicity were compiled and examined for 11 groups of South African marine invertebrates (2533 species). For five groups species richness adhered to a well-documented pattern, increasing from west to east, but for the other groups species richness was highest along the south coast, Endemicity was generally highest along the south coast, and lowest along the east coast, The data base was then analysed using several types of complementarity analyses, each producing a minimum set of potential reserve areas, which cumulatively represent all invertebrate species analysed, Approaches based solely on rarity, species richness and endemicity demonstrated individual biases, suggesting a need to combine all three interests. Combining the three techniques produced similar results to the individual analyses, showing conservation priorities to be highest along the east coast. Specifically, the areas of Port Elizabeth and Durban were ranked high in all analyses. Consistently, a total of 16 sites was necessary to represent all species analysed. Comparisons with similar analyses on fish and seaweeds revealed similar findings. Existing invertebrate records were shown to be biased towards centres of high sampling activity, demonstrating a need of future sampling attention in under-represented areas.
