There is limited information concerning the cetaceans inhabiting the coastal waters of Mauritius. This document details the sightings of cetaceans encountered during April 2008 – September 2014. Boat-based surveys were conducted throughout the year, primarily focusing on spinner and bottlenose dolphin populations that are important for the local dolphin-watching industry. More than 1246 hours over 749 days of surveys were spent searching for cetaceans. All cetaceans encountered were recorded. During 2013 and 2014, dedicated diversity surveys were conducted and 2443.6km of search effort was covered around the islands. The encounter rate was 0.025 cetacean sightings/km. Over the total study period 13 species were recorded from 1459 sightings. Species included: Megaptera novaeangliae, Stenella longirostris, Tursiops aduncus, Tursiops truncatus, Globicephala macrorhynchus, Stenella attenuata, Physeter macrocephalus, Mesoplodon densirostris, Feresa attenuata, Peponocephala electra, Grampus griseus and Ziphius cavirostris. In addition, there were strandings of Kogia sima and Ziphius cavirostris. The most common species encountered were spinner dolphins, Indo-Pacific bottlenose dolphins, humpback whales and sperm whales. As expected only humpback whales showed any seasonality in monthly encounter rates (Kruskal-Wallis H = 42.39, Hc = 54.25, p < 0.001). The overall Shannon diversity index was 0.58 (95% CI 0.57–0.60) though this ranged between 0.77 in 2009 to 0.25 in 2014. The Shannon index value for the diversity study was 0.83 (95% CI 0.74–0.91). This study demonstrates the richness of the waters around Mauritius and the importance of the area for beaked whales, migrating humpback whales and the presence of resident sperm whales.

When making decisions about reintroducing a species, practitioners need to consider whether the release site contains habitat suitable for those species, whether past extinction drivers have been remedied and whether reintroduction is the best option for the species to recolonize the release site. These concerns are captured within two paradigms; the habitat and metapopulation paradigms. We use cost‐distance analysis to assess the need for reintroduction of two bird species, Rodrigues Fody and Rodrigues Warbler, to Anse Quitor reserve on Rodrigues Island, testing hypotheses based on these underlying paradigms. Given a lack of detailed field studies of dispersal across the landscape on either species we rely on expert judgment. Our results show that experts believe Rodrigues Fody will naturally colonize Anse Quitor but that Rodrigues Warbler may not, at least within a time frame of 10 years. This information and treatment of expert judgment allows greater justification in reintroduction planning. Our method shows one way to assist in reintroduction decision making in poorly studied systems.