Much-needed work around ghost nets in the Arafura and East Timor Seas continues at NAMRA

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Much-needed work around ghost nets in the Arafura and East Timor Seas continues at NAMRA

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In lieu of the recent decision to cease funding to the award-winning conservation program GhostNets Australia, the need to inform the wider community about the value of efforts to clean up and protect local waters becomes distinctly apparent. Another program concerned with the health of North Australia’s marine ecosystems – the North Australia Marine Research Alliance (NAMRA) – builds research capacity relevant to the scale and variety of challenges to northern waters; challenges that are overwhelmingly yet to be met or even understood. NAMRA is a major strategic program under an alliance involving CDU (via RIEL), the Australian National University, the Australian Institution of Marine Science (AIMS) and the Northern Territory Government.

 


 

Kiki prepares to release Ollie the juvenile olive ridley turtle from his natal beach at Bare Sand Island. Photo by Nicola Brookhouse

Kiki prepares to release Ollie the juvenile olive ridley turtle from his natal beach at Bare Sand Island. Photo by Nicola Brookhouse

 

Ghost nets (fishing nets lost or abandoned at sea) are widely recognised as a major threat to marine life in the Arafura and Timor Seas (ATS). In recent weeks this has been highlighted by attention from concerned criticsmembers of the public and the media following the Federal Government’s decision to cut funding to the program GhostNets Australia. Despite this recent blow, the fight against these silent killers continues in current research undertaken by NAMRA’s Dr Kiki Dethmers.

 

Kiki is almost halfway through a 3-year postdoctoral research project that uses population genetics, satellite tracking and hydrodynamic modelling to look specifically at the impact of ghost nets on turtle species in the ATS. “There are a lot of species other than turtles that get entangled as well, but GhostNets Australia found in their removal of fishing nets washed up on the beaches that the animals entangled are primarily turtles,” she says.

“Human activity in the ATS hurts turtles in many different ways, but it’s certainly evident that ghost nets are one significant source of turtle mortality. Very little is known about turtle migratory patterns in the ATS, and still less is known about how ghost nets move in the area. A lot of work is needed to understand and manage the ghost net problem in Australia’s northern waters.”

Recently two juvenile marine turtles were released into the ATS, an event covered in both local and national media. The turtles, Henderson the flatback and Oliver the olive ridley, were rescued as disoriented and dehydrated hatchlings two years ago and raised in captivity at the Territory Wildlife Park. Kiki saw the opportunity to fit the turtles with satellite transmitters prior to their release, and track them as part of her research. Henderson and Oliver are two of three turtles currently being trackedin the ATS under this project.

“Oliver and Henderson were only released a couple of weeks ago so it’s too early to tell about things like species-specific behaviour or habitat preference, let alone their potential interaction with ghost nets,” Kiki says. “But I’m hoping that over time, Henderson and Oliver will give me a good insight where they like to hang out and how it relates to where those nets are.’”

Along with tracking turtle movements, Kiki is looking to understand how ghost nets move in the ATS. By simulating the deadly masses with oceanic drifters, Kiki will be able to track structures that mirror the way ghost nets hang in the water column to drift in subsurface currents.

“From monitoring how the oceanic drifters move we can look at whether ghost nets aggregate in any particular areas, no matter where they might enter the system,” Kiki explains. “So if there is an area where ghost nets aggregate that overlaps with an important turtle migration route or turtle feeding grounds, then conservation and management efforts and resources may be targeted in these areas.”

As for Ollie and Hendo (as they are now affectionately known), the chances they come across one of the tens of thousands of ghost nets floating in the ATS are greater following the closure of GhostNets Australia.

“One of the things GhostNets Australia found is that because of the removal of those nets off the beaches, those nets weren’t being recirculated" Kiki says. "They reckon they saw a decline in the number of nets washing up on the shore.

Kiki professes the hope that her research will restore government support for such programs that work effectively to manage ghost nets.

“I think it’s extremely unfortunate that GhostNets Australia are not able to continue their work any more," she continues. "In many instances this means that Indigenous ranger groups will no longer receive the support they need to remove the nets from their beaches and collect the information that has helped us gain a much better understanding of the ghost net problem."

 

NAMRA was established to increase capacity for marine science around the oceans and coastal environs of northern Australia. Kiki’s research is just one of six inaugural NAMRA postdoctoral projects started less than two years ago, focussing on challenges to North Australian waters.

“At the time NAMRA was being created, it was recognised that marine research in Northern Australia was fragmented and under-resourced,” NAMRA director Dr Ed Butler reveals. “NAMRA’s goal from the outset has been to work together to develop research collaborations to address major challenges posed to the North Australian marine estate by environmental change and sustainable development of natural resources for human use. By aligning their complementary strengths and by sharing resources and facilities, the Parties will enhance their capacity to address these issues.”

Although NAMRA’s funding is scheduled to end in July 2015, Ed reports that the program is evolving quickly, with NAMRA’s Management Committee contemplating plans to put the Alliance on more sustainable footing in the future.

Watch this space.

 

For more photographs of the turtle release from Bare Sand Island, check out the album on RIEL's Facebook page RIEL life.
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