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09 Aug 2021

Human activity said to be the main threat endangering humpback dolphins

Kristin Engel (Cape Argus: IOL) Picture: Sea Search Bridget James. The endangered Indian Ocean humpback dolphin, the first and only endangered marine mammal in South African waters.

Cape Town – A study by scientists and conservationists has shown that with fewer than 500 Indian Ocean humpback dolphins (Sousa plumbea) in South Africa’s oceans, a strict conservation management plan was needed to revive the Indian Ocean humpback dolphin from extinction. Human activity along the coast was found to be the main threat to the dolphin’s conservation.

The International Union for the Conservation of Nature and the Red List of Mammals of South Africa recorded the humpback dolphin to be the first and only endangered marine mammal in South African waters which led SouSA Consortium to conduct a study to identify the actions needed to ensure the conservation of this species – which was recently published in the Frontiers in Marine Science journal.

Stellenbosch University Pathology and the Bayworld Centre for Research and Education in Port Elizabeth Associate Professor Stephanie Plön said the consortium would continue to engage with government to declare Indian Ocean humpback dolphins a priority species for conservation and hoped their study could form the basis of a conservation management plan to ensure healthy gene flow in the population, prevent population segregation and improve habitat quality in critical coastal areas.

Plön said that while environmental factors affected the declining numbers of the species, individual threats and solutions were hard to identify with SA’s marine environment undergoing significant changes, often as a result of human activities such as coastal construction and pollution.

The study found the main threat to the conservation of the species to be the multiple and cumulative impacts of human activity in the coastal zone.

Nelson Mandela University’s Institute for Coastal and Marine Research co-author Dr Gwenith Penry said Operation Phakisa, an initiative established to develop the Oceans Economy, was an example of the unregulated growth of industries under economic imperatives without fully understanding the possible negative impacts that increased activity in the marine environment would have on ocean life.

“Growth in sectors like oil and gas exploration, marine transport, harbour development and fishing/aquaculture will increase noise levels in the ocean, introduce additional pollutants and could result in unintentional habitat partitioning,” said Penry.

Plön said the consortium was planning to engage with various stakeholders through increased outreach and education regarding the outcomes of their study.