Indonesian fishermen from the island of Rote have hunted sharks in the Timor Sea for generations.

But the falling price of shark fin in Hong Kong and China, a crushing debt cycle, and increasingly restrictive Australian maritime policies mean many are turning to what they see as the only other viable option for using their seafaring skills: people smuggling.

Rahman Djalilan comes from the village of Papela, on the island of Rote off West Timor.

Like most men in Papela, he has been a shark fisherman his entire adult life, sailing south on the eastern monsoon each year to the waters near Ashmore Reef.

The fishermen spend up to two months at sea, sleeping on deck, battling rough weather, and using long lines to reel in sharks for their fins.

In a good month, Mr Djalilan says he could make several hundred dollars.

But in 2012, a slump in Chinese demand caused shark fin prices to fall dramatically, having a huge impact on Papela's fishermen, many of whom are heavily indebted.

"We have thousands of dollars of debt. Even if we get a lot of fins, we can't pay the debt. Now we only get $50, sometimes $40 per month," Mr Djalilan says.

80 per cent of shark fishermen have considered people smuggling: researcher

Earlier this year, Mr Djalilan decided he would try his luck people smuggling.

"This risks of those jobs are the same. But people smuggling pays more than shark fishing," he says.

"The purpose was to earn a lot of money to be able to repay our debts to the shark fin boss."

But Mr Djalilan's trip was a failure. The motor on the shoddy boat provided by the smuggling boss broke down just off West Java, he was apprehended by Indonesian police and sent home with a warning. He was paid nothing.

Mr Djalilan's story is all too common in Papela.

Vanessa Jaiteh is a marine biologist from Murdoch University researching shark fishing in eastern Indonesia.

This year she spent three months in Papela, and interviewed more than 80 fishers.

"I'd say that 80 per cent of my respondents have said that they've thought about taking asylum seekers to Australia," she says.

Australian policies in Timor Sea have massive implications for Indonesian fishermen

Mr Djalilan's decision to become a people smuggler clearly has implications for Australia. But his story - and his crippling debts - are also intimately tied to Australian policies in the Timor Sea over the past four decades.

Starting in the 1970s, the area around Ashmore, Cartier and Scott reefs was progressively - and unilaterally - claimed by Australia as part of the country's expansion of sovereignty to 200 nautical miles from the coast.

In 1974, Australia signed a memorandum of understanding (MoU) with Indonesia, allowing "traditional" Indonesian fishermen to continue to fish in the area, which became known as the MoU Box.

A statement from the Australian Department of Agriculture, Fisheries and Forestry (DAFF) says the MoU was a gesture of good will recognising these communities' long history fishing in those waters.

"The MoU Box is one of the few places in the world where one country allows its neighbour access to its economic zone and permits extractive activities for the purposes of pursuing traditional fishing activities," it says.

Traditional Indonesian fishermen say they are turning to people smuggling amid falling prices for shark fins. ( ABC: Kate Evans )

But there are strict rules: fishing inside the Ashmore Reef marine reserve is banned, and the fishermen must use "traditional methods". Under the MoU, that is defined as fishing with long lines from wooden sailing boats with no motors.

These rules are a source of resentment among the Papela fishers. Almost every year, fishermen die at sea when their boats are caught in rough weather.

Tobi Nasrudin Ginang, a veteran Papela fisher, lost two of his sons in a storm last year.

"If they had had a motor maybe they wouldn't have died," he says. "They could have reached land before the storm came."

But DAFF says the MoU Box is already "over-fished and very depleted" and the rule helps to limit the amount of fishing, as there is no official list of "traditional fishers".

"The rule allowing only non-motorised vessels was a practical, enforceable and agreed definition for the traditional activities," the statement says.

"Winding back this rule would result in every fishing vessel in Indonesia potentially gaining access to the MoU Box."

Fishermen breaking rules risk losing boats, equipment and catch

When fishermen are caught breaking the rules, their catch and equipment are confiscated, and they are fined.

As they can rarely afford to pay they are imprisoned, paying back the fine through jail time.

In some circumstances, Australia also burns the fishermen's boats - although DAFF says that decision is not taken lightly.

In the mid-2000s, the Australian Navy in collaboration with Customs launched a crackdown on illegal fishing.

In 2006, the Australian Fisheries Management Authority says 359 Indonesian boats were apprehended fishing illegally in Australian waters. Most were destroyed.

Last year, that number dropped to 10, suggesting the policy has been a successful deterrent.

But in Papela it has had a lasting unintended legacy because most fishermen do not own their own boats or fishing equipment.

They are borrowed on credit from a local boss and paid back with the shark fin profits.

When the boats were burned, equipment confiscated or captains and crew jailed, fishermen like Mr Djalilan ended up with debts they are still trying to pay back - either by taking more risks shark fishing, or attempting people smuggling.

"My debt is reducing because I've kept shark fishing whatever the risks, and despite being caught I kept sailing to pay the debt and feed my wife and children."

Few other options for indebted fishermen

But are shark fishing and people smuggling really the only options for this community?

Rote is nothing like the fertile volcanic islands of Bali and Java to the north-west. It is remote, arid, ill-suited to agriculture, and is one of the poorest islands in Indonesia's poorest province, Nusa Tenggara Timur.

The fishermen say they can just survive by fishing off Rote, but it does not allow them to pay back their debts.

"We go fishing, but we never have anything left over. The money comes in and it's gone straight away," Mr Djalilan says.

"In Rotenese we say it allows us to 'keep breathing', but beyond that it's impossible to get more if we just fish locally."

A series of Australian Government initiatives have aimed to provide alternative livelihoods for the fishers, including a scheme to grow seaweed in Papela harbour. So far, though, these have had limited success.

"It's very difficult to find solutions," marine biologist Vanessa Jaiteh says.

"Basically a solution has to be economically equal or better than shark fishing, and in these remote areas where the access to markets is very difficult, tourism is not really an option."

According to DAFF, "the greatest assistance we can offer to the traditional fishers is to try to restore and manage more healthy fish stocks in the MoU Box. The saying goes like this: 'A fisherman's best alternative is a well-managed fishery'."

But in the meantime, fishermen like Mr Djalilan believe they are left with little choice.

"Bringing immigrants is illegal. I didn't want to do it," he said.

"But the economy is so low. So I was forced to try it - whatever the risks."