There are growing concerns about Indonesian fishermen illegally killing and eating protected turtles off Australia's northern coast, with authorities confirming eight animals have been found slit open with their eggs removed.
The green turtles were found on two remote islands north of Broome, during a patrol by the Department of Biodiversity, Conservation and Attractions (DBCA).
The department said in a statement that the carcasses had "what appeared to be man-made slits in the side of their bodies where eggs had been removed".
"Turtle experts and government agencies are unanimous in their belief that Indonesian fishermen are responsible, given the remote location and method of killing."
The grim discovery comes amid the biggest spike in illegal foreign fishing in Australian's northern waters in almost 20 years, which has local boat skippers concerned about the threat of piracy and the impact on marine life.
'Entirely opportunistic'
The dead turtles were found on beaches at Scott Reef and Browse Island, which are located several hundred kilometres off the Kimberley coast.
The Australian National University's Professor James Fox, who has studied Indonesian fishing practices for more than 40 years, said the killing of the turtles was an unusual occurrence.
"If the turtles were cut open and the eggs taken out, I'd suspect it was Indonesian [fishermen]," he said.
"I would suggest it's entirely opportunistic, and done by fishermen who probably have not previously sailed into this area before."
The targeting of turtles coming ashore to nest has alarmed marine scientists, as green turtles are listed as a threatened species and only breed in a handful of remote beach rookeries.
The department has told the ABC there are fewer than 500 adult females in the area around Browse Island and Scott Reef, making it the smallest known genetic stock of green turtles in Australia.
Pair records 'frightening' encounter
Disturbing footage has also emerged of Indonesian fishermen coming ashore on a remote sandbar littered with empty, dead turtle shells.
The videos, posted on YouTube, show two young travellers discovering the large empty shells on the beach, which is located within Australian waters.
They then have a frightening late-night encounter with several Indonesian fishermen, who come ashore looking for a cigarette lighter.
A few days later the pair provide water and food to a boatload of fishermen who ask for supplies, with one man pointing to a raw wound on his leg.
New data shows big spike
The incidents come as federal government figures show a significant increase in the number of illegal foreign fishing vessels detected in Australian waters over the past 18 months.
Peter Venslovas, from the Australian Fisheries Management Authority (AFMA), said there had been a huge spike in boats being intercepted so far this financial year.
"In comparative terms, we haven't experienced those types of numbers since the mid-2000s, when the numbers peaked."
The increase in illegal fishing has been linked to the COVID pandemic, which has reduced other forms of income for many Indonesian communities.
Some of the fishing villages are also struggling to rebuild economically in the week of cyclone Saroja, which caused extensive damage in April 2021.
Prior to the COVID pandemic, illegal fishermen were often brought to the mainland to be prosecuted and deported.
That hasn't occurred over the past two years due to pandemic safety concerns.
But authorities insist they are continuing to enforce the marine boundaries as best as possible, by seizing illegal catches and fishing equipment, and escorting boats out of Australian waters.
In the past 12 months, 44 illegal boats were destroyed and burnt at sea, because there were enough vessels in the fishing convoy for those who had been on the burnt boats to safely return home on other vessels.
Indonesian media campaign
Mr Venslovas, the general manager of AFMA's fisheries operations branch, said an education campaign had been launched in Indonesia to try to deter fishermen from making the trip to Australia.
"We have recently created video animations in both Bahasa [Indonesian] and English, and they outline the rules associated with illegal fishing and the consequences if you are caught fishing illegally," he said.
There are indications the campaign may be having an effect, with a moderate reduction in illegal boats being detected this year compared with the second half of last year.
But some experts are warning the 'whack-a-mole'-style scenario will continue until the Australian government invests in long-term solutions to reduce demand for highly sought-after Australian marine life — especially trepang, or sea cucumber.
Which means the green turtle population off Australia's north-western coast remains in danger.
Surging demand for slimy delicacy
The illegal fishing trade is built on demand for trepang, which is on-sold to China.
Professor Fox monitors the international trade, and warns demand for the seafood delicacy is booming.
"Over the past year and a half the market price for some species of sea cucumber has gone astronomical in the Chinese market, where there's a big increase in wealth," Professor Fox said.
"They've been fished out in Indonesia but remain in abundance at the northern tip of Australia, so it's really just a matter of supply and demand."
Professor Fox warns fishing crews will continue to set sail for Australian waters, despite tragedies such as the drowning of nine Indonesian fishermen when their boat sank off Ashmore Reef in March.
"There will be more boats and more rogue elements coming down, to take their chance making a killing on trepang."
Professor Fox says the development of a trepang harvesting industry along the Indonesian coast would help to reduce the number of fisherman making the treacherous trip south.