Murdoch University study suggest Hawaii’s spinner dolphins may be negatively affected by constant human exposure


Hawaiian spinner dolphins may be negatively impacted by their constant exposure to humans.
Hawaiian spinner dolphins may be negatively impacted by their constant exposure to humans.

SPINNER dolphins, a major drawcard in Hawaii’s $14 billion tourism industry, may be negatively impacted by their near constant exposure to humans, according to a new study carried out in partnership by Murdoch and Duke universities.

Spinner dolphins are famous for delighting onlookers by performing spins when leaping high out of the water.

Researchers, including Julian Tyne from the Murdoch University Cetacean Research Unit, discovered the wild dolphins keep a strict daily schedule that does not allow them much downtime from humans.

“The dolphins mainly rest between 10am and 4pm upon their return to sheltered near-shore habitats,” Dr Tyne said.

“We also observed that socialising behaviour occurred mainly in the early mornings and late afternoon within bays.”

Dr Tyne said strong social bonds between dolphins may be important to the success of their co-operative night-time foraging.

“We are not aware of any other cetacean species that partitions its behavioural activities in such a constrained manner on a 24-hour basis,” he said.

Dr Tyne said the strict schedule might mean spinner dolphins would struggle to recover from disruptions.

“Over the last 30 years, human activities have increased significantly in Hawaii,” he said.

“This small genetically isolated spinner dolphin population is chronically exposed to human activities for more than 82 per cent of the time during daytime hours.

“To our knowledge, these are the highest reported exposure rates of any free-ranging coastal dolphins to human activities.

“Human activities can affect the health of individuals through lost time conducting important behaviours like foraging and resting, leading to negative impacts on vital rates and population viability.”

The US National Marine Fisheries Service has announced plans to protect the spinner dolphins in Hawaii from human disturbance by proposing a rule which prohibits swimming with and approaching a Hawaiian spinner dolphin within 45m.