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

J Kiszka,A Amon,C Muir

doi:10.4314/wiojms.v6i1.48230

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.

Highlights

The dugong (Dugong dugon Müller 1776) is the only herbivorous mammal that is strictly marine and is the only member of the family Dugongidae
Most of the information on the status of the dugong in the lagoon of Mayotte is anecdotal. This information, combined, provides an important basis from which to develop conservation and management plans. This assessment indicates that dugongs do still occur in Mayotte waters but historical data and recent sightings suggest that numbers are low
Historical data provided by local fishermen showed that dugongs were common in the lagoon of Mayotte before the 1980s

Summary

Introduction

The dugong (Dugong dugon Müller 1776) is the only herbivorous mammal that is strictly marine and is the only member of the family Dugongidae It is the most abundant sirenian, and occurs in the waters of at least 48 countries and territories of the Indo-Pacific region from east Africa to Vanuatu, between 26° and 27° north and south of the equator The eastern Africa coast/western Indian Ocean region is the western boundary of the dugong’s global range. They occur in small numbers off Somalia, Kenya, Tanzania and Mozambique as well as off the islands of the Seychelles, Comoros, Madagascar, and Mayotte (Marsh et al, 2002; WWF EAME, 2004). In Mayotte, as in the other states of the western Indian Ocean (including Madagascar), the status and distribution of dugongs is poorly known and data

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