Capture-mark-recapture modelling suggests an Endangered status for the Mayotte Island (eastern Africa) population of Indo-Pacific bottlenose dolphins

Abstract

We evaluated whether the Indo-Pacific bottlenose dolphins around the fast-developing island of Mayotte are threatened. We used opportunistic photo-identification data and capture-mark-recapture models to estimate key demographic parameters and then assessed the conservation status of the species using the IUCN Red List regional criteria. The population home range was estimated with the minimum convex polygon method as 978 km2, the annual abundance was estimated from closed population models as 82 ±19 SE individuals and the annual survival rate was estimated using a Cormack-Jolly-Seber model as 0.937 ±0.059 SE. From the data available, we believe migrations of individuals between Mayotte and its neighbouring islands are likely but would not exceed a few individuals per year. Based on IUCN guidelines for classification at local scales, we classified Indo-Pacific bottlenose dolphins around Mayotte as Endangered. We strongly recommend the establishment of a long-term population-monitoring program and the implementation of management measures.