In most industries, the crimes would spark an international outcry: Thousands of tons of a prized commodity stolen every day, leaving a long trail of victims and frustrated authorities.

The commodity is fish. And the crime—illegal fishing—accounts for up to $23.5 billion worth of seafood every year. The perpetrators roam the global ocean, often in huge vessels that net immense hauls of fish. They operate without regard for the environment, often poaching from marine reserves or severely damaging habitat, such as coral reefs, in pursuit of fish. They steal wherever and whenever they can, frequently targeting the high seas or waters of coastal countries that lack the resources to monitor and enforce their territories.

Many of the bad actors are well-financed and highly organized, selling their illicit catch through poorly monitored ports and exploiting a system beset by complexities and loopholes that make it very difficult to convict and punish criminals.

The victims? Illegal fishing hurts law-abiding fishermen by diminishing available stocks and driving market prices down. It also affects coastal communities around the world that rely on sustainable fisheries for food and income. And there’s an even darker side to this story: Illegal fishing has been linked to a host of other crimes, including labor abuse and enslavement of crews, drug and arms smuggling, and human trafficking.

Although it has taken years, governments and the international community are finally acting to end illegal fishing and mete out punishments that fit the crimes.

These steps include the June 2016 entry into force of the Port State Measures Agreement (PSMA), a U.N. treaty designed to strengthen and harmonize the inspection processes for foreign-flagged fishing vessels coming into ports. Historically, illegal fishermen who were turned away at one port could simply continue on their way, trying other ports until finding one that accepted their catch. With the PSMA, governments now have a blueprint for determining which vessels are most likely to have illicitly caught fish and for detaining or seizing that catch when appropriate. Port officials in countries that have ratified the agreement—50 so far, in addition to the European Union—are also obligated to inform neighboring countries after turning away suspected illegal fishermen, which should make it much harder for offenders to find a port that will take their catch. More countries are expected to ratify soon, and the treaty grows stronger with each new member.

Another major obstacle to catching and prosecuting suspected illegal operators has been the difficulty in identifying vessels. Unlike cargo, merchant, and other classes of ships, fishing vessels are not universally required to have permanent unique identifying numbers. As a result, criminal fishermen often change their flags of registration, radio call signs, and even vessel names to throw authorities off their trails. These tactics have worked surprisingly well: In one case, crew members of a suspected illegal vessel were photographed painting a new name on the hull even as authorities closed in—a move that helped them avoid arrest and continue fishing.

Now, numerous governments and fishery management bodies are requiring that all vessels over a certain size carry International Maritime Organization numbers: unique, permanent identifiers that stay with vessels until they’re scrapped. Expanding this requirement to the entire commercial fishing industry will make it much easier for governments and authorities to know which boats are operating illegally and which have histories of suspicious activity.

Another common tactic of illegal fishermen has been to simply head for another country’s waters or to the high seas whenever authorities initiate a pursuit. This too has worked well, because most governments lack the time and resources for an extended chase.

Enter Interpol, the International Criminal Police Organization, which in 2013 launched Project Scale in partnership with Pew and the Norwegian government. The initiative, which helps Interpol’s 192 member countries share information on suspected illegal fishermen, has helped catch numerous offenders, including the owners of the Kunlun, a vessel suspected of poaching millions of dollars’ worth of toothfish from the Southern Ocean. In 2016, Spain led a successful administrative case against those owners, fining them $18.5 million (17 million euros) and banning them from involvement in commercial fishing for up to 23 years.

By tapping into Interpol’s network and resources, national authorities around the world can better determine when and where to pursue suspect ships. And additional progress is now possible thanks to a platform called Oversea Ocean Monitor. Developed by Pew and the U.K.-based firm Satellite Applications Catapult, the platform enables countries to monitor activity in their waters or on the high seas using the vast reach of satellites, combined with data on vessels’ ownership, licensing, history, and more.

The platform processes information from multiple sources—including space-based radar and photographic imagery, vessels’ electronic transponders, and databases of authorized and blacklisted vessels and oceanographic and environmental data—to help analysts focus on ships that, for example, might be fishing in marine reserves or shutting off their automatic location transponders in an attempt to poach undetected. Chile, Costa Rica, Ecuador, and Thailand use Oversea Ocean Monitor, which has also been employed to monitor waters around the Pitcairn Islands, a British overseas territory in a remote area of the South Pacific Ocean. The island nation of Palau, which has made fighting illegal fishing a top priority, will start using the platform soon.

Together, these efforts are driving positive change, from the water to seafood markets and restaurants. But the global community still has a fight ahead to end this crime. Because illicit operators will carry on as long as they can profit, it’s imperative that all of us who care for the ocean join with the millions of people who depend on the ocean to continue our work to end illegal fishing.

Tom Dillon is a vice president overseeing The Pew Charitable Trusts’ international environment portfolio.