The August seizure of a refrigerated ship carrying shark parts in the Galápagos Islands Marine Reserve cast a global spotlight on the illegal trade in protected species, but the case of the Chinese-flagged Fu Yuan Yu Leng 999 is only a ripple in the watery underworld of illicit fishing.

Illegal fishing could account for as much as 26 million tons of fish annually, or more than 15% of the worldwide catch, according to the U.N. Food and Agriculture Organization (FAO). That could skew figures used to calculate fishing quotas, leading to overfishing and population collapses.

“One of the main problems [with illegal fishing] is that there are no precise figures,” says Alejandro Flores, senior fisheries and aquaculture officer with the U.N. Food and Agriculture Organization in Panama. “There’s a very rough global estimate, but obviously we don’t have scientific data about the volumes.”

Because industrial fishing boats operate on the high seas, out of sight of regulators, illegal fishing is sometimes accompanied by other forms of organized crime, including drug trafficking and slave-labor working conditions.

But technology is beginning to shine a light into that world. Real-time satellite tracking makes it more difficult for ships like the Fu Yuan Yu Leng 999 to cover their tracks. And the FAO is helping Latin American coastal countries beef up their oversight of vessels arriving in their ports. Nevertheless, those systems are only as effective as the enforcement behind them.

“Fish is money, and money is politics,” says Francisco Blaha, an international consultant who got his start on Argentine fishing boats and is now based in New Zealand. “Fishery problems are management problems. We have the capacity and the tools [to address them]. What we don’t have is the political will.”

There are some exceptions, however. In May 2016, an Argentine naval vessel sank a Chinese trawler that was fishing illegally in its exclusive economic zone (EEZ), the area within 200 nautical miles of its coast. Some months earlier, Argentine ships had pursued another Chinese fishing vessel, which escaped, but which was detained in April 2016 by Indonesian authorities acting on a request from Interpol.

In the case of the ship in the Galápagos Marine Reserve, where it is illegal to catch sharks or even to transport them, Ecuador fined the ship’s owner US$5.9 million and a court sentenced the captain to four years in prison, three of the vessel’s officers to three years each and 16 crew members to one year each. (See “Shark-laden Chinese ship seized near Galápagos”—EcoAméricas, Aug. ’17.) It was not immediately clear, however, where the refrigerated cargo ship, or “reefer,” had loaded the sharks, some of which were endangered species.

That’s where technology comes in. Global Fishing Watch, a website that was created by the nonprofit organizations SkyTruth and Oceana with help from Google, offers real-time tracking of fishing vessels.

Authorized industrial fishing boats generally have a vessel-monitoring system (VMS) that gives their location. Virtually all, including those that are not authorized to fish in particular areas, have automatic information system (AIS) transponders designed to avoid accidents.

Using freely available data from those transponders, SkyTruth analyst Bjorn Bergman saw an odd jog in the route that the Fu Yuan Yu Leng 999 took as it crossed the Pacific from China to the Galápagos.

Homing in on that spot, he found that the refrigerated cargo vessel had slowed while other vessels traveled close beside it—an indication that they might have been transferring fish to the larger ship, a procedure known as transshipment.

In Ecuador, crew members testified that the Fu Yuan Yu Leng 999 had rendezvoused with two Taiwanese ships during the period Aug. 5-7, but when Bergman searched for fishing vessels in the area at the time, he found that four Chinese ships had probably tied up to the reefer instead. The next step will be to track those vessels’ movements before the encounter, Bergman said.

Reefers take on fish from trawlers and provide some provisions. That allows the fishing vessels to remain at sea longer; otherwise, they would have to head for port more frequently to unload their catch and resupply. When satellite tracking systems see a reefer traveling slowly with a fishing vessel close beside it, this often indicates that transshipment is occurring, according to Nathan Miller, a SkyTruth data scientist working with Global Fishing Watch.

Although such transshipment is legal, it can also be a way of mixing legally and illegally caught fish, effectively “laundering” the illegal catch. A Global Fishing Watch study released earlier this year found 5,000 likely and 86,000 possible transshipments worldwide between 2012 and 2016.

Two transshipment “hot spots” were identified in South American waters, one at the edge of Peru’s EEZ, where several hundred vessels fish for giant squid (Dosidicus gigas), and the other off Argentina.

In international waters near the edge of Argentina’s EEZ, an even larger fleet of Chinese, Taiwanese, Korean and Spanish vessels captures species including Argentine shortfin squid (Illex argentinus), Argentine hake (Merluccius hubbsi), hoki (Macruronus novaezelandiae) and Patagonian toothfish (Dissostichus eleginoides).

“In the South Atlantic, squid is a key species in the ecosystem,” says Milko Schvartzman, a former Greenpeace campaign coordinator who now works as a marine conservation consultant. “It’s an important food for hake, dolphins, sperm whales, elephant seals, penguins and albatross.”

There are few studies of the impact of industrial fishing on those marine species, but there are some indications that it could be reducing food supplies for penguins and seals, Schvartzman says.

The Global Fishing Watch data ranked Montevideo, Uruguay, the second most-visited port for refrigerated cargo vessels. Ships offload their catch, which is then loaded into containers for shipping to Europe or the United States, making certification of the fish’s origin murky, Schvartzman says.

A Chinese company, ShanDong BaoMa Fisheries Limited, is reportedly negotiating with the Uruguayan government to build a US$200 million port near Montevideo, with freezer storage, a shipyard and refueling facilities. There is talk of designating it a free-trade zone, which Schvartzman says could make monitoring more difficult.

Although every country regulates fishing within its own waters, fishing on the high seas—and fishing of species that “straddle” boundaries—is regulated by more than a dozen regional fishery-management organizations. Some govern geographic areas, while others concentrate on certain species, such as tuna. Those organizations also keep lists of vessels authorized to fish in the relevant areas or for the relevant species.

The organizations’ member countries—those whose waters are in the region or whose fleets fish in those zones—draw up rules for managing key species. Because multiple countries must agree, however, decision-making can be slow, says Juan Carlos Sueiro, a marine scientist in Oceana’s Peru office.

The organization that governs fishing in the eastern Pacific, for example, has mainly regulated horse mackerel (Trachurus trachurus). But the boom in fishing for giant squid, by a fleet that moves back and forth along the boundaries of Ecuadorian and Peruvian territorial waters and into the central Pacific, points to a need to establish quotas for that species, too, Sueiro says.

The heavily fished South Atlantic region has no management organization, partly because of the conflict between Argentina and Britain over the islands known as the Malvinas or Falklands. A bilateral organization set up to share biological data and information about foreign fishing fleets disbanded about a decade ago.

Closing regulatory loopholes that allow or encourage illegal, unregulated and unreported fishing requires a combination of technology, national policies, and inter-agency cooperation to make fish legal and traceable from ocean to plate, experts say.

“You need [an] interlocking series of mechanisms,” says Mark Young, senior officer of the Washington-based Pew Charitable Trusts project on illegal fishing. “Too much over the past 20 or 30 years has been done in a jigsaw manner that leaves room for loopholes and gaps in oversight.”

Oversight can be conducted in three places—the country whose flag a vessel is flying, the country where the vessel fishes, and the country where it calls at a port.

The flag state is responsible for ensuring that vessels flying its flag operate within the law, but some countries that allow the use of their flags for a fee lack adequate oversight capability, Blaha says. Even landlocked Bolivia and Mongolia are flag states.

Countries can decide whether to allow foreign trawlers to operate in their waters and can enforce their regulations in those waters; but even though tracking systems are becoming more feasible, they do not always have the resources to monitor the vessels.

Port states—such as Uruguay, with its busy Montevideo port, or Peru, with Callao and Chimbote—can play a key role in catching or discouraging illegal operations by requiring ships to identify themselves clearly and to request permission to enter the port; denying entry to those suspected of illegal activities; checking paperwork and inspecting the cargo of ships in port; and coordinating among different agencies to scrutinize labor conditions and watch for illegal cargo, as well as inspecting fish.

Those are among the measures recommended in a 2009 FAO Agreement on Port State Measures to Prevent, Deter and Eliminate Illegal, Unreported and Unregulated Fishing, which took effect in June 2016. Latin America and Caribbean signatories include the Bahamas, Barbados, Brazil, Chile, Costa Rica, Cuba, Dominica, Guyana, Peru, St. Kitts and Nevis, and Uruguay. The FAO is currently working with Latin American countries to set up an information-sharing network to help countries improve oversight, Flores says.

Tracing the origin of fish to guarantee that they were caught legally can be more complicated, but there, too, technology can help. The human observers who work on some fishing boats can be supplemented by video monitoring and an electronic reporting system to ensure that fish are not “laundered” during transshipment or with falsified paperwork, Young says.

Blaha advocates making electronic information, including vessel location and catch volumes, publicly available in order to render the entire fishing chain more transparent.

“The fisheries problem is not a biological problem,” he says. “It’s a policy problem. It’s countries playing together. If you don’t have transparency, you won’t have a solution.”