Genetic study reveals vulnerability of northwest dolphins

Jul 02, 2014

New study estimating population genetic structure of little-known dolphins inhabiting Western Australia's north coast highlights vulnerability, according to a study published in the open-access journal PLOS ONE by Alex Brown from Murdoch University and colleagues.

Australian snubfin and humpback dolphins occur throughout tropical coastal waters of northern Australia, but little is known of their abundance or life history characteristics because of their remote range. "Both snubfin and humpback dolphins are listed as 'near threatened' by the IUCN, but the lack of information about them has prevented a comprehensive assessment of their conservation status," Alex said. "The few studies conducted to date suggest that they occur in small populations that are dependent on the coastal environment and are, therefore, sensitive to coastal habitat modification." Large-scale industrial development is occurring across north-western Australia, resulting in modification to coastal habitats through dredging, construction and increased shipping. With so little data on coastal dolphins in this region, the potential impact of these developments remains unknown.

Using small tissue samples collected with a dart, the researchers compared the genetic characteristics of two populations of each species - snubfin dolphins from Roebuck Bay and Cygnet Bay in the Kimberley region and humpback dolphins from the North West Cape and the Dampier Archipelago in the Pilbara.

"Results showed that there wasn't much mixing between the populations," Alex said. "They are fairly isolated, with low levels of gene flow between populations separated by about 300 km of coastline".

"Existing as a series of with limited gene flow, they are more vulnerable to environmental change and localised extinctions compared to a single, larger ," explained senior author Dr. Celine Frère of the University of the Sunshine Coast.

The researchers are urging management agencies to treat the as small, discrete fragments and to preserve corridors for individuals to travel between populations.

In another first, Alex documented the first recorded hybrid between a humpback and snubfin dolphin. "We were at first puzzled by this unusual looking dolphin," said Alex. Genetic analysis revealed it to be the offspring of a snubfin dolphin mother and father. "It really highlights how little we know about these animals," he added.

Explore further: Roebuck Bay, a special place for snubfin dolphins

More information: Brown AM, Kopps AM, Allen SJ, Bejder L, Littleford-Colquhoun B, et al. (2014) Population Differentiation and Hybridisation of Australian Snubfin (Orcaella heinsohni) and Indo-Pacific Humpback (Sousa chinensis) Dolphins in North-Western Australia. PLoS ONE 9(7): e101427. DOI: 10.1371/journal.pone.0101427

Related Stories

Roebuck Bay, a special place for snubfin dolphins

May 26, 2014

One of the great scientific surprises in recent times is how an inshore dolphin with a melon shaped head and smiley mouth, was discovered as Australia's first endemic species of dolphin as recently as 2005.

Rare Chinese white dolphin gets DNA bank

Jan 15, 2012

A Hong Kong conservation group said Saturday it has set up a DNA bank for the rare Chinese white dolphin, also known as the pink dolphin, in a bid to save the mammals facing a sharp population decline.

Dolphin food habits distinguish genetic line

May 08, 2014

Indo-Pacific bottlenose dolphins that use sponges as hunting tools are eating different foods to those who do not and the unique behaviour could have shaped the genetic makeup of the population, according ...

Health check for Swan River dolphins

Jan 20, 2014

Murdoch University researchers have commenced a new study investigating the health of the dolphins inhabiting the Swan Canning Riverpark.

Recommended for you

Birds 'weigh' peanuts and choose heavier ones

46 minutes ago

Many animals feed on seeds, acorns or nuts. The common feature of these are that they have shells and there is no direct way to know what's inside. How do the animals know how much and what quality of food ...

Estuaries protect Dungeness crabs from deadly parasites

20 hours ago

Parasitic worms can pose a serious threat to the Dungeness crab, a commercially important fishery species found along the west coast of North America. The worms are thought to have caused or contributed to ...

An evolutionary heads-up—the brain size advantage

21 hours ago

A larger brain brings better cognitive performance. And so it seems only logical that a larger brain would offer a higher survival potential. In the course of evolution, large brains should therefore win ...

Our bond with dogs may go back more than 27,000 years

May 21, 2015

Dogs' special relationship to humans may go back 27,000 to 40,000 years, according to genomic analysis of an ancient Taimyr wolf bone reported in the Cell Press journal Current Biology on May 21. Earlier genome ...

User comments : 0

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.