If you’ve longed for adventures on the high seas but couldn’t live the dream for whatever reason, your time has come. On Sept. 15, film star and environmental activist Leonardo DiCaprio unveiled Global Fishing Watch for the public at the US State Department’s Our Ocean 2016 conference. It’s a free tool that allows anyone with an internet connection to track the activities of fishing vessels on the world’s oceans.

The goal? Get the public engaged in illegal fishing, which makes up 35 percent of the global wild marine catch, according to the UN Food and Agriculture Organization. This, DiCaprio and the state department believe, will put pressure on the fishing industry to play nice or risk exposure and the ire of the people.

The notion is that knowing what’s going on is the first step in garnering interest and turning individuals into activists. Or, as DiCaprio said at the conference, “This platform will empower citizens across the globe to become powerful advocates for our oceans.”

Global Fishing Watch is partially funded by the actor’s eponymous foundation. It contributed $6 million to the $10.3 million project created by Google Earth Outreach, an arm of Google that uses company infrastructure to work on environmental issues; SkyTruth, a nonprofit that shares satellite imagery and remote sensing data in defense of natural resources; and the international ocean advocacy organization Oceana.

Here’s how it works: Certain types of vessels with commercial purposes, in the US those longer than 65 feet, must report coordinates according to national and international maritime rules using an Automatic Identification System (AIS), or shipboard broadcasting. This is required by navigation agencies to avoid collisions.

For the crowd-spying platform’s purposes, the data is collected via satellites and analyzed using machine learning to identify fishing behavior based on the vessels’ movements. The coordinates reported by law to ensure safety are then processed by the platform. Global Fishing Watch users can look at data collected over the past four years.

Before you begin your environmental espionage, one caveat: to keep prices low so the technology could remain free, Phys.org reports, the new platform negotiated a deal with the communications technology company Orbcomm for “near real-time” data—information that is three days old, as well as past records. (Presumably, real-time data would be costlier.) That means you won’t be seeing any illegal activity as it happens.

Note, too, that vessels engaged in illegal activities can—and do—try to spoof the AIS system by providing false information. Crews can manually enter incorrect longitudes and latitudes into their AIS transmitters and upload these to satellites, which read them as legitimate GPS data. But Ami Daniel, CEO of marine analytics firm Windward, told Fast Company that tricking the system like this doesn’t work in the long term because erratic behavior can be spotted over time…which is just one reason why Global Fishing Watch wants more eyes on the high seas.