The invertebrate benthos, especially the micro- and mesofaunal components, of the Brazilian seas is still poorly known. Relatively few species have been recorded, reflecting the lack of research in this field. The intertidal zone, to depths of about 20 in, has been studied the most, and there the numbers of endemic species are relatively high. The diversity of demersal and pelagic fishes is similar among the major marine regions, and endemism is typically low (<5%) and restricted to reef species. Surveys in southeastern Brazil (depths of up to 2000 in) have recorded more than 1300 species of benthic animals, of which the Porifera, Cnidaria, Sipuncula, Gastropoda, Bivalvia, Scaphopoda, Polychaeta, Crustacea, Ophiuroidea, Bryozoa, and Brachiopoda were the most abundant or frequent Excepting the molluscs, decapods (brachiurans), cirripeds, and echinoderms, the faunas of salt marshes, coral reefs, and islands remain poorly known. Marine and estuarine demersal teleosts include 617 species in 26 orders and 118 families. Just over half the species (337) are Perciformes. Overexploitation, for food and by the aquarium fish trade, habitat degradation and destruction, alien species introductions, pernicious tourism, and pollution are the principal threats to Brazil's marine biodiversity. The Minister of the Environment lists 34 threatened and 10 overexploited or at risk of being overexploited benthic species. Fishes officially listed as threatened include 15 species of sharks and rays and 7 teleosts. Another six elasmobranchs and 27 teleosts are currently or potentially being overexploited. Conservation of marine biodiversity in Brazil is still broadly inadequate despite existing legislation and several protected areas. The number and size of marine protected areas are insufficient, and some still lack management plans or have yet to receive the appropriate measures and infrastructure to make them effective. Fisheries administration and management is still precarious and in many areas lacks effective participation of local communities. Major conservation initiatives include the identification of keys areas for biodiversity conservation, surveys, intensified monitoring of fisheries, environmental education, and the creation and improved management of protected areas.193625631