Phase IV – Dugongs (Dugong dugon) of the Western Indian Ocean Region: – Identity, Distribution, Status, Threats and Management

Coastal marine megafaunal populations often bear the brunt of human marine resource use as increasing human populations attempt to meet their demands of food and energy security. In particular, direct exploitation, bycatch in fisheries, indirect ecosystem effects of fisheries, unregulated tourism activities, potential disturbance from hydrocarbon exploration and extraction, deteriorating water quality, shoreline and coastal development, and climate change are potential anthropogenic stressors of coastal marine megafaunal populations within the coastal waters of the Western Indian Ocean. Furthermore, the synergistic and compounding effects of many of these anthropogenic impacts are unknown.

Dugongs (Dugong dugon) have an extensive range across an estimated 140,000 km of coastline of some 48 countries in near-shore tropical and subtropical coastal and island waters of the Indo-Pacific between southern Mozambique in the west and Vanuatu to Japan in the east. While major strongholds of dugongs occur in Oceania and the Arabian Sea, the status of populations over a large proportion of the Indo-Pacific Ocean range is unknown, particularly within the Western Indian Ocean. A brief review of known contemporary distribution and abundance suggests that dugongs have declined markedly across their Western Indian Ocean range (within the coastal waters between Kenya and Mozambique, and in the coastal watrs of the Mascarene Island Nations) over the last 30 years, and that the status of the East African dugong meta-population is in dire need of re-evaluation.

This Project aimed to investigate the conservation status of dugongs across the region about identified threat issues, and identify a series of appropriate management strategies for implementation at regional and national levels.  Such conservation processes require some steps, including;

1. Identification of the range through habitat modelling; 
2. Population genetics analyses across the range to determine population identity; 
3. Abundance estimation and trend estimation (where previous abundance estimates exist);
4. Simulation modelling (PVA or PHVA) of population trajectories where declining trends have been identified;
5. The identification of threats and impact hotspots where populations are threatened; and 
6. The identification and implementation of management strategies to mitigate anthropogenic population stressors. 

In summary, the Project assesses the status of dugong populations as indicators of overall ecosystem health in the Western Indian Ocean across the coastal waters of Kenya, Tanzania, Zanzibar, Mozambique, the Comoros Islands (excluding Mayotte) , and the Seychelles. It ties into a UNEP/CMS GEF project application within Madagascar and the Bazaruto Archipelago of Mozambique.