Year-round, divers from all over the globe make pilgrimages to Indonesia’s colorful waters, which are known for being a world-class diving location. Indonesia is, among other things, a known biological hotspot for sharks and rays, and you may therefore be lucky enough to experience whale sharks, hammerhead sharks and manta rays up close. In other words, Indonesia is on most divers’ list and diving tourism brings in at least 22 million dollars a year. But every single day lots of sharks and rays are caught and cut up in the country’s many fishing grounds and harbours. The trade in sharks and rays is large, and nowhere else in the world are as many sharks and rays caught as in Indonesia. At the same time, this makes the tropical island kingdom one of the world’s largest exporters of shark and ray products, where shark fins are the most valuable. The high demand has in a few decades made a big dent in the stocks. Both sharks and rays are particularly vulnerable to massive fishing, because they take a long time to reproduce and have only a few young. The species cannot therefore keep up with and reproduce the over 100,000 tonnes that are caught every year by small and large fishing boats in the sea around Indonesia. Scientists have long claimed that the number of sharks and rays globally has fallen by 70 percent over the past 50 years. Difficult to catch illegal fishing The trade in fish and marine animals is therefore highly regulated today: some species are fully protected on the CITES convention’s global list of trade in wild animals and plants, which must not be caught or sold. Other species are subject to strict national and international trade rules. But the chain from a shark being caught by a local fisherman in Indonesia, to its finding its hands as shark soup in an exclusive restaurant, is long and has many links. This makes it incredibly difficult for the authorities to monitor whether regulations are being complied with. Illegal fishing and trade in endangered and protected species is therefore a major problem in the populous country. It was precisely the almost impossible working conditions for Indonesia’s fisheries inspectors that gave Andhika Prasetyo the idea for a new and ground-breaking DNA method that will make it easier, faster and cheaper to monitor the trade in sharks and rays. He currently holds a PhD and is a marine scientist at Indonesia’s National Research and Innovation Agency and previously worked in the country’s Ministry of Fisheries. – When I saw how my colleagues looked like a needle in a haystack in the large containers filled with everything from tuna to sailfish in factory areas the size of badminton courts, where some dealers try to hide the illegal species, I thought that it must be possible in a different way. Over several years, Andhika Prasetyo developed and tested a new DNA technique that, instead of only taking random samples from a single fish, uses a whole pile of tiny pieces of skin and cartilage from all kinds of fish, which are swept up directly from the floors of warehouses and fishing facilities. Andhika Prasetyo and his research colleagues have dubbed the small fragments of the DNA samples “shark dust” in their scientific investigation, which has just been published in the journal Conservation Letters: – We started the work already in 2019, when everyone who worked in nature conservation and biology spoke on environmental DNA metabarcoding. So when we wrote the application to get financial support, the only limit was the imagination. The project ended up being a major collaboration between, among others, the Indonesian and British governments, says Prasetyo and continues: – Perhaps you remember the film Stardust? We call it “shark dust” because we hope that when people hear it, they get an image of something magical happening, the researcher explains on a video connection from Indonesia. Great need and potential Over two months, they visited the seven cities that act as the hub for trade in shark and ray products on Indonesia’s main island of Java. Here they collected a total of 28 different samples, which consisted of two tablespoons of shark dust. As much as 84 percent of the genetic remains the researchers found in the dust came from CITES-listed species. Among other things hammerhead shark, silky shark, manta ray and manta ray. Andhika Prasetyo anticipates that many more species will be added to the CITES list in the coming years. There will therefore be even more use for better tools for the people who work to ensure that the rules for the trade are followed and respected. Andhika Prasetyo says that the Indonesian government has invested in biotechnology facilities, among other things, after the survey was finished. At the same time, he and his colleagues are busy raising funds for seven machines for the DNA analyzes directly at the country’s trading hotspots. They have also taught employees from the ministry how to collect and analyze the shark dust. But it will be quite a challenge to control the fisheries in Indonesia. The country is the world’s largest archipelago and consists of over 17,000 islands, which stretch over several thousand kilometers and three time zones. As Andhika Prasetyo explains, it provides a countless number of places across the country where fishermen can catch endangered and protected sharks and rays. – DNA metabarcoding is not a solution that can stand alone. The problem is so extensive and it is also about the fact that Indonesia’s local population is dependent on shark meat as both an important source of income and food. But it is a crucial piece in strengthening Indonesia in complying with the laws to protect the endangered species.
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“Shark dust” reveals illegal trade in endangered species in Indonesia
