Indian Ocean Humpback Dolphin
(Sousa plumbea)
SCIENTIFIC CLASSIFICATION
CURRENT THREATS
CURRENT STATUS
SPECIES OVERVIEW
The Indian Ocean humpback dolphin is an endangered coastal species found throughout shallow nearshore waters of the Indian Ocean. Known for its distinctive humpbacked profile and slate gray coloration, this dolphin is among the most at risk cetaceans in Africa. In Kenya, fewer than 200 individuals are estimated to remain, occupying bays, estuaries, and coastal habitats where they are especially vulnerable to entanglement in fishing gear, habitat degradation, and increasing human activity. These combined pressures place significant strain on already small and fragmented populations, underscoring the urgent need for targeted conservation action.
SPECIES RANGE
The Indian Ocean humpback dolphin occurs along the coastal waters of the western Indian Ocean, with its range extending from eastern Africa through parts of the Indian Ocean basin. The species is most commonly found in shallow nearshore habitats, including bays, estuaries, and reef-associated waters. Populations are typically small and localized, with limited movement between regions, making them particularly vulnerable to habitat disturbance and localized threats.
THE PROBLEMS
Indian Ocean humpback dolphins face a range of human-driven threats that place intense pressure on already small and fragmented populations. Accidental entanglement in fishing gear is a major cause of injury and mortality, particularly in shallow coastal waters where artisanal and commercial fisheries overlap with dolphin habitat. Coastal development, pollution, and habitat degradation further reduce the quality and availability of critical nearshore areas used for feeding and social behavior.
Increasing boat traffic and other human activities also raise the risk of disturbance and injury, while limited population sizes reduce the species’ ability to recover from losses. Together, these threats make localized populations especially vulnerable and highlight the need for targeted conservation efforts focused on protecting coastal habitats and reducing human impacts.
WHAT WE ARE DOING AND WHY
Recognizing the urgent need for action, Operation GRACE partnered with Kenya Marine Mammal Research Conservation (KMMREC) to launch Kenya’s first marine mammal response training workshop in Watamu. Supported by the Kenya Wildlife Service (KWS), the Smithsonian Institution, and the Wildlife Conservation Society (WCS), the program equipped veterinarians, biologists, government personnel, and fishers with critical skills in health assessments, stranding response, and post-mortem investigations.
Since then, local teams have conducted dozens of coastal surveys, documenting the largest known group of Indian Ocean humpback dolphins in Kenya, approximately 60 animals foraging at the Tana River mouth.
With mentorship from NMMF biologists, survey teams now use photo-identification and drones to track body condition and entanglement scars, advancing long-term monitoring capacity. NMMF has also strengthened the Kenya Marine Mammal Stranding Network through hands-on training and support during recent strandings.
Looking ahead, efforts will expand into Kwale County to address a 60-kilometer gap in dolphin survey coverage, strengthen citizen science, and improve government coordination. Together, these initiatives are building a strong foundation for the long-term protection of Kenya’s humpback dolphins.
Acoustic Monitoring
Researchers have long used underwater recorders to detect vaquita clicks. Building on that foundation, we began developing smart acoustic buoys that can identify vaquitas in real time, relay data instantly, and alert teams to nearby vessels – creating faster, more effective protection for this critically endangered species.
Drone-Based Health Assessments
We initiated development of SEAHAWC, an AI-enabled drone designed to identify individual vaquitas, assess health, and monitor for illegal fishing activity, all without disturbing the animals. Training local community members in its operation will ensure lasting, locally led protection for vaquitas.
HOW YOU CAN HELP
Your support helps protect the Indian Ocean humpback dolphin and other vulnerable species through Operation GRACE and the National Marine Mammal Foundation’s science-driven research, veterinary expertise, and conservation action. Donations directly support health assessments, rescue and response efforts, and collaborative fieldwork with local experts to better understand threats, improve survivability, and protect the river ecosystems these dolphins depend on.
