International collaboration working to enhance protections for spinner dolphins

January 13, 2017
International collaboration working to enhance protections for spinner dolphins
A spinner dolphin takes flight. Credit: J.Tyne – Image taken under NOAA permit GA LOC 15409

An international study involving researchers from Western Australia and the United States has unlocked a key behavioural schedule in spinner dolphins, which could provide crucial insight to conservation measures for the free-ranging animals.

Spinner dolphins are famous for performing spins when leaping high out of the water and are a major draw card in Hawaii's $14billion tourism industry.

Researchers from Murdoch University- in partnership with Duke University - studied the of Hawaii Island, finding they display a unique daily behavioural schedule.

"The dolphins mainly rest between 10.00 and 16.00 upon their return to sheltered near shore habitats. We also observed that socialising behaviour occurred mainly in the early mornings and late afternoon within bays," said Dr Julian Tyne from the Murdoch University Cetacean Research Unit.

"Reinforcing social bonds and social cohesion between the dolphins may be important for success of their cooperative night-time foraging activities.

"We are not aware of any other cetacean species that partitions its behavioural activities in such a temporally and spatially constrained manner on a 24-hour basis."

Dr Tyne said such constraints may render spinner dolphins less able to compensate for disruptions to their behavioural schedule.

"Over the last 30 years human activities have increased significantly in Hawaii, but the spinner dolphins still inhabit those areas that are important for resting. Recent abundance estimates are lower than all previous estimates indicating a possible long-term impact," continued Dr Tyne.

"This small genetically isolated spinner dolphin population is chronically exposed to human activities for more than 82 per cent of the time during day time 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 constrained behavioural pattern displayed by the spinner dolphins may make them less able to compensate for disturbance, compared with species that display a more variable behavioural pattern."

The United States National Marine Fisheries Service (NMFS) 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, instead of time-area closures.

"Quantification of the spinner dolphin behavioural schedules provides critical insight for conservation measures that aim to mitigate the effects of human disturbance," Dr Tyne added.

"It is therefore essential that NMFS consider the constrained nature of the spinner dolphin's daily behavioural schedule when proposing rules to reduce harassment from human activities."

Explore further: Scheduled bay closures proposed to protect Hawaiian spinner dolphins

Related Stories

Assessing threats to Hawai'i's spinner dolphins

January 23, 2014

(Phys.org) —Researchers have completed the most extensive study of the Hawai'i Island spinner dolphin population to date, with the data to be used to inform the local management agency.

Feds seek rules for swims with Hawaii dolphins

March 11, 2016

Allison Alterman likes to swim in the ocean for exercise near her home on Hawaii's Big Island. Sometimes her swimming group will see spinner dolphins gliding or jumping near their course.

Policy action urgently needed to protect Hawaii's dolphins

December 17, 2014

The best way to protect wild spinner dolphins in Hawaii while also maintaining the local tourism industry that depends on them is through a combination of federal regulations and community-based conservation measures, finds ...

New maps may reduce tourism impacts on Hawaiian dolphins

August 27, 2012

Over-eager eco-tourists intent on seeing spinner dolphins up close may inadvertently be disturbing the charismatic animals' daytime rest periods and driving them out of safe habitats in bays along Hawaii's coast.

Recommended for you

World's smallest tape recorder is built from microbes

November 23, 2017

Through a few clever molecular hacks, researchers at Columbia University Medical Center have converted a natural bacterial immune system into a microscopic data recorder, laying the groundwork for a new class of technologies ...

A possible explanation for how germlines are rejuvenated

November 23, 2017

(Phys.org)—A pair of researchers affiliated with the University of California and Calico Life Sciences, has discovered a possible explanation regarding how human germlines are rejuvenated. In their paper published in the ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.