Tue. Dec 7th, 2021

You would not think that shooting a dolphin could help save it.

But marine scientist Carol Palmer uses a specially converted rifle to collect small DNA skin samples from rare snubfin and humpback dolphins and fake orcas off the remote Wesseløer of Arnhem Land.

“The Wessel archipelago is probably one of the most unique places in the northern territory because it is so remote and because we capture dolphins, whales, turtles and manta rays – we have recorded some amazing species here,” said Dr. Palmer, a research assistant at Charles Darwin University.

The university and Gumurr Marthakal Aboriginal rangers have teamed up to document the species and investigate why this is a hotspot for biodiversity.

They expect to prove that the marine megafauna around Wessels are genetically distinct populations to those on Australia’s east and west coasts.

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Dr. Palmer said it would mean that Wessels and other similar hotspots along Australia’s northern coastline would have to be individually protected if these species were to survive in the long term.

“With a few more DNA skin tests, I’m sure we’ll find that the fake killer whale population here is a coastal population, and then we can upgrade its conservation status,” she said.

A woman is holding a rifle and standing in front of a boat at sea.
Dr. Carol Palmer uses a specially converted rifle to collect skin samples from dolphins and whales.(ABC News: Michael Franchi)

“Also with the dolphins, we will be able to confirm that we have discrete populations, and then that will mean we have to have a really different approach to management.”

Currently, Australian fake killer whales are officially listed as “deficient data”, while snubfin dolphins are considered “vulnerable”.

The partners are also attaching satellite tags to track the movement of large male green turtles, which they believe are falling around the islands.

A fake killer whale swimming in the sea.
The marine scientists hope to prove that fake orcas found from Wessels are a separate population.(Delivered by: Carol Palmer)

Marine life is facing growing threats

For Marthakal ranger Marcus Mungal Lacey and Wessels’ Yolngu traditional owners, the sea creatures are not only important creatures in their homeland, but also as ancestral spirits.

“This place is a center of the clans on the mainland because of the important totemic animals that created this area and play an important role in all the cultural creation stories,” he said.

Currently, the rangers have only two ships to cover an area of ​​15,000 square kilometers.

Wessels is a three to five hour boat ride from their base on Elcho Island, 530 miles east of Darwin.

A male ranger and female scientist, followed by several other people talking as they walked along an otherwise empty beach.
Marthakal ranger Marcus Mungul Lacey and marine scientist Dr. Carol Palmer works with monitoring terrestrial and marine animals on the islands.(ABC News: Michael Franchi)

Lacey said the rangers were extremely concerned about rising threats from overfishing, marine litter and abandoned fishing nets.

“The biggest threat is from ghost nets torn from fishing boats that have been driven by the current – it’s pretty dangerous for the animals,” he said.

Rangers and researchers are also concerned about the growing threat from climate change.

“The weather is warming up and the ocean is warming up, but we can do nothing but turn away from all the things that are causing climate change,” said Dr. Palmer.

Ghost nets on the beach at Marchinbar Island
The Marthakal rangers fight a constant battle with ghost nets and marine debris washing up on beaches part of the Wessel Islands. (ABC News: Jane Bardon)

Future financing hopes

The research partners are assisted by ranger groups from the Kakadu, Cobourg, Darwin and Tiwi islands and several other Australian universities.

They hope the information they gather will help persuade governments to devote more resources to protecting northern waters.

“The work that comes out of this will hopefully bring more funding to more additional work that needs to be done,” Lacey said.

Dr. Palmer said: “There has been so little work done in the Northern Territory of the sea world, so we hope this starts an ongoing program that would be similar to what is going on. [at] Ningaloo Reef in Western Australia and Great Barrier Reef in Queensland. “

An underwater photo of a large manta ray swimming in a blue sea.
Researchers are taking small skin samples from manta rays to find out if they are different from those from Australia’s east and west coasts.(ABC News: Jane Bardon)

A refuge for endangered mammals

On Wessel’s rock outcrops, rangers and researchers also trace some of Australia’s last populations of endangered animals, including the golden bandicoot and northern quoll.

“These places are really important havens for our wildlife because they do not have many of the threats we get on mainland Australia – toads, feral cats, pigs, horses and cattle,” said Sam Banks, Charles Darwin University’s Director of Environmental Research.

“Seeing quolls, golden bandicooters and rock wallabies jumping around on the beaches is just amazing.

A northern quoll lying on a piece of cloth while holding someone's hands.
Endangered northern choke thrives on the Wessel Islands, where there are no wild predators.(ABC News: Michael Franchi)

Partners are planning more bushfire prevention work after three-quarters of the mammal’s habitats on Marchinbar, the largest of the Wessel Islands, were destroyed last year.

To test whether the small size of the quoll and bandicoot populations puts them at risk for diseases caused by inbreeding, the researchers take small DNA samples from their ears.

They think that some of them may benefit from being paired with different mates.

A rock wall that sits on rock formations along an island coastline.
Endangered rock walls can often be seen bouncing around on the islands’ beaches. (ABC News: Michael Franchi)

“With a small number of animals, you can lose genetic diversity or make inbreeding patterns happen pretty quickly,” Professor Banks said.

“In particular, the people of Marchinbar Island actually have a very low genetic diversity.”

Professor Banks said the Tasmanian devil in the facial tumor was an example of a disease that could come out of the left field and “you just do not have the adaptability to deal with it”.

“So what used to happen in other parts of the world has been moving animals from other islands, just to reintroduce a little bit of new genetic material,” he said.

Two scientists are working while sitting on a sandy beach, with greenery in the background.
Dr. Carol Palmer and Professor Sam Banks set traps on Marchinbar Island to monitor strangulation and golden bandicoot populations.(ABC News: Michael Franchi)

Traditional owners want to return

No one has lived on the Wessel Islands since the 1960s, after smallpox brought by seafarers and cyclones destroyed small communities.

But the traditional owners’ rock articles deal with thousands of years of trade with Indonesian sea cucumber fishermen, sea hunting, sailing ships, dolphins, fish and dugongs.

“This is our museum and a library where everything is stored,” Lacey said.

“The paintings tell amounts of in-depth knowledge, but very spiritual knowledge.”

A man standing in the water next to a beach, holding a long spear, at sunset
Traditional owner Travis Didimurrk and his family hope to one day return to live on the Wessel Islands.(ABC News: Michael Franchi)

The traditional owner Frank Warrindjuna Gandangu said seeing the paintings, after many years away from the islands, had increased his desire for his people to return and live there.

“The country is always waiting, the country is calling too,” he said.

“There is a positive energy flowing from that painting, to give strength, to say: this is your home, this is where you belong.”

Aboriginal rock art of crocodiles and dugongs on a rock wall.
Wessel’s rock art documents Yolngu’s traditional owner’s relationship with animals, including crocodiles and dugongs. (ABC News: Michael Franchi)

Plans for island ranger base

For that to happen, the Aboriginal clans would need infrastructure upgrades, including a new runway.

Marthakal rangers hope to establish a permanent ranger base at Marchinbar as a first step towards being able to monitor the environment and cultural heritage there more closely.

“We have to come home to take care of it and work with the rangers and all the other teams working to save our country,” Gandangu said.

An aerial photo of several people standing on a piece of white sand surrounded by rock formations and greenery.
The islands are home to several species of endangered mammals, which leave abundant traces.(ABC News: Michael Franchi)

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