Terrestrial and freshwater molluscs are amongst the most threatened of all taxa, yet data exist on the distribution and status of only a small proportion of the species. Here we present the results of the first systematic survey of a terrestrial mollusc on the island of Príncipe in the Gulf of Guinea. Archachatina bicarinata has never been previously surveyed, despite being categorized as Vulnerable on the IUCN Red List and suffering from unregulated harvesting for food. We found that A. bicarinata is restricted to primary rainforest and its abundance and probability of occurrence increased as surveyed sites became less accessible. Additional anecdotal evidence from the observations of previous scientific expeditions, local guides and snail harvesters suggested that the species has suffered a dramatic decline in population size and distribution in recent years. We therefore recommend that immediate action be taken to prevent its imminent extinction on Príncipe. The collection of A. bicarinata from protected areas should be banned, as should commercial harvesting and sales. Subsistence collecting should be limited to larger individuals. Our data have been used to inform the management plans for the protected areas on Príncipe and São Tomé, and this should help to ensure the future of A. bicarinata on both islands.

São Tomé and Príncipe is an archipelago located in the Gulf of Guinea. This archipelago seems to be an important area for cetaceans, probably due to large concentrations of prey, as well as the existence of several small bays and shallow water that constitute preferred rest areas. In comparison to other areas of the world, little is known about cetacean communities in this archipelago. Boat-based surveys to record sightings of cetaceans were conducted between 2002 and 2005, which represents the first approach to study the occurrence of whales and dolphins in this tropical region. Sightings of humpback whales (Megaptera novaeangliae), bottlenose dolphins (Tursiops truncatus), pantropical spotted dolphins (Stenella attenuata), killer whales (Orcinus orca), sperm whales (Physeter macrocephalus) and pilot whales (Globicephala melas) were recorded. Cetaceans were found throughout a range of sea surface temperature between 24 and 29°C and a wide range of depths. Significant differences were found regarding the occurrence of some species. Humpback whales showed a preference for shallower waters between 20 and 100 m. Bottlenose dolphins occurred most commonly along the continental shelf (20 to 100 m) and pantropical spotted dolphins occurred in deep slope waters (>1000 m).