Status of a Marginal Dugong (Dugong Dugon) Population in the Lagoon of Mayotte (Mozambique Channel), in the Western Indian Ocean

Abstract

The dugong (Dugong dugon) is one of the most endangered mammal species in eastern Africa. Dugongs are exposed to many human-induced threats, such as by-catch in fishing gears and deliberate killing. In order to understand the conservation and management issues surrounding this species status assessments are needed. An assessment was conducted in Mayotte (Comoros, Mozambique Channel) in 2003 to determine the status and distribution of the dugong. Questionnaire surveys were carried out in August 2003 with local fishermen. Results of opportunistic sightings were collected from 1999 to 2005 (n=53), and aerial surveys were undertaken between July and November 2005. The three data sources provide historical and actual data on the status of the species. Dugongs were common in the lagoon before the 1980’s, and then declined significantly due to hunting pressure and by-catch in fishing nets. In the 2000’s, opportunistic sightings have been made regularly by recreational dive operators and microlight aircraft pilots. Recent sightings indicate calving in the lagoon of Mayotte, with several observations of mother-calf pairs. Measures to protect Mayotte’s marine biodiversity, such as establishing a network of Marine Protected Areas, banning fishing nets and developing pelagic fisheries is expected to help ensure the future survival of the dugong in this area.