IUCN Red Lists Assessments of Dugong sub-populations

In 2021, the CMS Dugong MOU commissioned two sub-regional assessments of priority dugong sub-populations in East Africa and New Caledonia under the IUCN Red List framework. The assessments aimed to strengthen the scientific basis for conservation planning and improve understanding of extinction risks faced by geographically isolated dugong populations. The assessments were compiled by Professor Helene Marsh, Co-Chair Emeritus of the IUCN Sirenian Specialist Group and Professorial Fellow at James Cook University. They drew on multiple sources of information, including historical records, community interviews, genetic studies, and aerial survey data. 

East Africa Dugong Sub-population 

The assessment identified the East African dugong sub-population as small and geographically restricted. Based on aerial surveys conducted in 2021, the number of mature individuals was estimated to be critically low. More than 90 per cent of the remaining sub-population was found to occur within the Bazaruto Seascape of Mozambique, while sightings elsewhere in East Africa were too infrequent to support reliable abundance estimates. Following submission of the assessment to the IUCN Red List, the East African dugong sub-population was classified as Critically Endangered, indicating an extremely high risk of extinction in the wild. 

New Caledonia Dugong Sub-population 

The assessment confirmed that the New Caledonian dugong sub-population is both geographically and genetically isolated. Based on aerial surveys conducted between 2003 and 2012, the number of mature individuals was estimated to be between 149 and 896. Genetic analyses indicated that dugongs in New Caledonia constitute a single genetically homogeneous sub-population encompassing all mature individuals in the region. This limited genetic diversity and restricted geographic distribution increase the sub-population’s vulnerability to catastrophic events, including disease outbreaks and large-scale declines in seagrass habitats. Following submission of the assessment to the IUCN Red List, the New Caledonian dugong sub-population was classified as Endangered, indicating a very high risk of extinction in the wild. 

Threats Identified 

Both assessments identified significant and ongoing threats affecting dugong sub-populations and their habitats, including:  

Climate change was identified as a compounding threat to the long-term survival of both sub-populations, particularly due to the restricted geographic distribution of the East African sub-population and the geographic isolation and genetic homogeneity of the New Caledonian sub-population. 

Conservation and Management Considerations 

The assessments reviewed existing conservation measures and management frameworks relevant to dugong conservation. This included consideration of national and international legal frameworks, hunting regulations, existing Marine Protected Areas (MPAs), the effectiveness of management measures for dugong and seagrass conservation, and ongoing research and monitoring activities. The findings highlighted the urgent need to strengthen conservation action,  reduce anthropogenic pressures and improve the long-term viability of these vulnerable dugong sub-populations. 

Contribution to the CMS Dugong MOU 

The assessments contribute directly to the implementation of the Dugong MOU Conservation and Management Plan, particularly in the areas of research and monitoring, threat mitigation and evidence-based conservation planning. They also demonstrate the importance of conducting assessments at the sub-population level to identify localized extinction risks that may not be fully reflected in species-level global assessments. The resulting IUCN Red List classifications provide an important scientific basis for prioritizing and targeting conservation action across Dugong MOU Range States. Further Information 

The full assessment reports are available for download: 
East Africa IUCN Dugong Assessment – 2022 
New Caledonia IUCN Dugong Assessment – 2022