In 2021 the CMS Dugong MOU commissioned two IUCN sub-regional assessments on the priority dugong populations of New Caledonia and East Africa.
Compiled by Prof. Helene Marsh, Co-Chair IUCN Sirenian Special Group Emeritus Professor in Environmental Science and a Professorial Fellow at James Cook University, the assessments draw on historical records, community interviews and aerial surveys in collaboration with regional organizations and field experts.
In the case of the geographically isolated East African subpopulation, the assessment found that the number of mature dugongs is now estimated to be less than based on aerial surveys conducted in 2021. Of particular note, over 90% of this population occur in the Bazaruto seascape of Mozambique and sightings elsewhere in East Africa are too infrequent to estimate abundance.
Following submission of this assessment to the IUCN Red List, the East Africa dugong sub-population has been classified as Critically Endangered, the highest level of extinction risk before a species is declared extinct in the wild.
In the case of New Caledonia’s dugongs, a geographically and genetically isolated subpopulation, the assessment found that the number of mature dugongs is now estimated to be between 149–896 individuals, based on aerial surveys conducted from 2003 to 2012. Of particular note are the genetic studies that suggest New Caledonian dugongs are one homogenous subpopulation harbouring 100% of the mature individuals, which considerably reduces the likelihood of successful repopulation following a catastrophic event (i.e. disease or widespread seagrass die-off).
Following submission of this assessment to the IUCN Red List, the New Caledonian dugong subpopulation has been classified as Endangered, also denoting high risk of extinction in the wild.
Both assessments provide details on the ongoing threats to the two dugong subpopulations, including anthropogenic pressures such as illegal hunting, boat strikes, incidental capture in gillnets, degradation of seagrass and unsustainable fishing techniques. Climate change is also highlighted as a threat to both subpopulations’ survival, particularly due to their geographical limitation (East Africa) and genetic homogeneity (New Caledonia).
Ongoing conservation efforts towards protecting both dugong subpopulations and their habitats is also analyzed. This includes a summary of relevant national and international legislation, hunting regulations, a review of existing Marine Protected Areas (MPAs) and their effectiveness towards dugong and seagrass conservation.
“Earlier this year, we published a study that found the Chinese dugong population is functionally extinct – now two more dugong populations are one step closer to disappearing forever,” said Professor Samuel Turvey, Zoological Society of London. “From habitat pollution to warming oceans, ongoing human impacts continue to prevent marine ecosystem recovery, threatening the future of both these iconic animals and the many other species they live alongside. We need urgent action to fight climate change and biodiversity loss, as these two crises simultaneously threaten life on earth as we know it.”