It’s tough to spot illegal fishing boats hiding among 17,000 islands. But Indonesia has a new tool to do just that — one that’s about the size of a shoebox and weighs only 4.5 kilograms.

This satellite is not only tiny and light, but also designed to listen — rather than look — for certain data.

“In theory, you could try to take pictures all the time of all the oceans, though 90 percent of the time, you wouldn’t see anything, and half the time there would be clouds in the way,” said Peter Platzer, the chief executive of Spire Global, a San Francisco–based startup that is working with the Indonesian government on the project.

But with radio sensing, a network of Spire satellites can keep track of ships’ transponders in near-real time, which can alert officials to a potential illegal fishing expedition.

“We want the ability to detect and monitor all vessels operating in Indonesian waters, allowing us to determine whether a particular vessel is a fishing boat or an illegal ship,” said Susi Pudjiastuti, Indonesia’s minister for marine affairs and fisheries, when announcing the work with Spire.

How do they work?

Platzer said the brains behind his first nanosatellite were pretty basic — a memory card similar to the ones used in most cellphones, and a GoPro, a popular camera often used to make surfing videos.

Since the satellites are so small, they can “hitch a ride” on bigger launches that are delivering satellites as large as buses. This allows the system to provide worldwide coverage at a lower cost than their heavier, more expensive cousins.

A Spire satellite hooked up to a testing device (Spire)
A Spire satellite undergoes testing in San Francisco. (Spire)

Every year, Indonesia loses an estimated $20 million and countless stretches of coral reefs to illegal fishing. Worldwide, these losses total in the billions. New satellite technology can help governments allocate ships to enforce fishing laws to cut down on this activity.

To combat illegal fishing, the United States is working with Indonesia to protect sustainable fisheries.

The U.S. also has joined the United Nations’ Port State Measures Agreement, which prevents the unloading of illegally caught fish in a country’s ports.