Indonesia is reaping the results of its aggressive crackdown on illegal, unreported and unregulated (IUU) fishing that began in late 2014, with figures and research showing that the effort is paying off.
Some of the Jakarta government's headline-making efforts included destroying 380 fishing vessels caught poaching in its waters, most of them from China, Vietnam, Malaysia and the Philippines. They included the Viking, a notorious Nigerian-flagged vessel that had been on Interpol's wanted list for poaching protected species in Antarctic waters. But the wrecking has also become a controversial issue between Indonesia and the countries of origin of the maritime plunderers.
Problems in the regional fishery sector were high on the agenda when Indonesian Foreign Minister Retno Marsudi visited Hanoi on April 17 to hold talks on bilateral cooperation with her Vietnamese counterpart Pham Binh Minh.
"IUU fishing is a serious threat to food security," Ms Retno said in a statement from the foreign ministry, adding that both sides had agreed to increase cooperation to combat organised transnational crime, especially related to fishing, and to push for a sustainable fisheries management.
The most recent capture of an illegal fishing vessel poaching in Indonesian waters involved the STS-50, which was seized on April 6 based on a request from Interpol in waters off Weh Island in Aceh province.
Fisheries Minister Susi Pudjiastuti said in a news conference on April 7 that the vessel was stateless and had dodged authorities in China and Mozambique while operating under different names and using flags from eight countries, including Cambodia and the Philippines.
She said the vessel was carrying 600 illegal gillnets with a total length of 30 kilometres and had 20 Indonesian crew, whom the authorities believed were victims of human trafficking.
"We seized this vessel as a show of our international solidarity and commitment against illegal fishing. We want this to be an example to the world that we don't compromise with those involved in transnational organised fisheries crime," she said.
On April 7, a ministry patrol boat also intercepted two Philippine-flagged vessels fishing illegally in the Sulawesi Sea, which borders on Philippine maritime territory, making a total of 26 illegal fishing vessels captured from January to April 10. The haul included three ships from Vietnam, two from the Philippines, one from Malaysia and 20 from Indonesia.
The crackdown on IUU fishing has proved to benefit Indonesia, according to researchers from the University of California, Santa Barbara (UCSB), who reported their findings in a paper published in Nature Ecology and Evolution in March.
"Indonesia's anti-IUU fishing policies draw a lot of media attention and speculation about their effect, but no one has demonstrated or evaluated the efficacy of the policies," Reniel Cabral, the paper's main author and a scholar at the Bren School of Environmental Science & Management in UCSB, was quoted as saying in Science Newsline.
"Indonesia has done a fantastic job of controlling illegal fishing in their waters. But for them to continually capture benefits from their anti-IUU fishing policies, they need to ensure that domestic fishing efforts are also well managed."
The Fisheries Ministry said earlier this year that the value of Indonesian exports of fishery products had increased from US$3.78 billion in 2016 to $4.09 billion in 2017. Ministry secretary-general Rifky Effendi Hardijanto said non-tax state revenues from the fisheries sector had risen from 214 billion rupiah ($15.4 million) in 2014 to 490 billion rupiah in 2017.
Christopher Costello, the paper's co-author, said Indonesia's tough stance on illegal fishing not only provided an impetus for recovery in its waters but also provided a feasible example for countries all over the world afflicted by overfishing and illegal activity.
"Overfishing is still a global problem," said Gerd Kraus, the director of the Thünen Institute, a federal research centre of the German Ministry for Food and Agriculture in Hamburg.
"Fisheries management globally has largely failed, in the European Union and everywhere else in the world," added Rainer Froese, a scientist from the Geomar Helmholtz Center for Ocean Research in the north German city of Kiel.
This is even more of a problem in the EU which is a net importer of fisheries products and where fishing capacity has been decreasing at a rate of 2% annually, Kraus said.
In 2016, Mr Froese published a study showing that only 15% of EU fish stocks were in good health and 69% were overexploited.
The EU is the world's largest importer of fishery products, accounting for 25% of the world's imports. Fisheries imports from Indonesia to the EU in 2016 were valued at €374 million or only 1.6% of the EU total, providing more room for growth in one of the largest markets for Indonesian fisheries products.
Ms Susi said at a news conference on April 19 that the fisheries export quota to the EU is still limited with only 177 Indonesian companies holding export approvals from the 28-country bloc. She said the government was currently helping 22 companies to obtain EU approval, which can only be acquired based on compliance with strict standards related to hygiene, traceability and compliance to human rights.
The availability of fish in the ocean is also threatened by climate change, with 90% of the temperature increase due to greenhouse effects taking place in the upper 2,000 metres of the oceans, said Mr Kraus.
This has led to changes in distribution areas of fish stocks, overall reduced productivity, biodiversity and ecosystem health. Mr Froese said predictions show it's getting too warm for many species to live in tropical waters and they will leave to go to subtropical waters or they will go deeper so fish stocks will be more difficult and expensive to catch.
"That is still 10 to 20 years away but it will come and you should prepare for that," he said, adding that tropical waters have the advantage of enabling fish to grow faster. As a result, the recovery could be twice as fast as in temperate waters. Reducing fishing for a short time will allow stocks to double in size and result in higher catches for a long time in the future.
"This calls for flexible and adaptive governance and management systems," Mr Kraus said, adding that the growing demand for aquatic food will probably have to be covered by aquaculture in the future, when the amount of fish taken by maritime activity will surpass natural reproduction.
He said aquaculture is the fastest-growing food-producing sector with half of all fish for human consumption now being farmed.
Scientists at the Liebniz Centre for Tropical Marine Research (ZMT) in Bremen, Germany have conducted research on a method to develop co-culture, or the use of more than one aquaculture product together. It uses waste from one species as fertilisers or food for another, combining feed and extractive aquaculture.
Andreas Kunzmann, head of ecophysiology at ZMT, said the method, called integrated multithropic aquaculture (Imta), is being used in Indonesia to develop seaweed and sea cucumber.
The latter, he said, is a key component in marine ecosystems, has a high value and is rich in protein but is severely overexploited in Indonesia.
"From our research, a properly managed Imta programme can accelerate growth with no detrimental side effects. It can also increase profits and reduce financial risks due to weather, disease and market fluctuations," Mr Kunzmann said, adding that co-culture offers a more efficient use of limited coastal space, but it is extremely difficult to convert fishermen into fish farmers.
As land availability and ground water become more scarce, aquaculture offers higher growth at 7.5% compared with 2% for agriculture overall and flat growth in the maritime fishery.
"Only mariculture has the potential to grow independently from mineral fertilisers, land and fresh water," Mr Kunzmann said.