On a September fishing expedition, Capt. Greg Weaver—owner of fishing charter E-Fishinsea in Virginia Beach, Virginia—grabbed his Garmin 7608, the GPS goliath’s chartplotter, and loaded a map. But it wasn’t directions Weaver was viewing; it was a layout to exactly where he could find pelagic fish in open waters. 

If you’ve ever seen a heat map, you’ll have a pretty good idea what this looks like: Colored blobs lay atop images of the ocean, with each color representing a different species of fish: Lime green for marlin, for example, fuchsia for wahoo, and red for yellowfin. And on that August day, Weaver headed straight for the lime-green oval on his screen. He caught enough marlin to satisfy customers, but perhaps more importantly, the fishing of all species, Weaver says, “was on fire.” 

“There's a lot of pressure on a charter—on the captain who's running the boat,” Weaver explains. “You're up all night thinking about where to point the boat in the morning. I used to lose sleep.”

These fishing maps help amateur and professional fishermen tremendously, taking much of the guesswork (and intuition) out of the where-to-go-to-find-fish equation. But interestingly, this service doesn’t come from marine biologists or ichthyologists; it comes from space. 

The fish-mapping service is a partnership between Maxar Technologies—a space tech company based in Colorado—and SiriusXM, the same subscription service that lets you to listen to your favorite tunes commercial-free. It was released in September to much fanfare from global fishermen. While it’s not the only fish-mapping service in the game, this product might be the most comprehensive: It covers all coasts, and is the only service to include the locations of weed lines—floating algae and plants that provide nutrients and cover for baitfish, which can attract the attention of prized game fish. 

Maxar Technologies collects raw, level-one and level-two satellite data—reconstructed, unprocessed, full-resolution, time-referenced, and annotated data—from NASA and NOAA. That data undergoes atmospheric corrections, then is passed on to a team of five oceanographers, who analyze the data—split into geographical squares of 18 by 18 degrees—over the course of a half day, says Vipul Prasad, Maxar’s head of marine services. Half of those squares are crunched on Monday and Thursdays, the others on Tuesdays and Fridays, covering the globe in a week. 

Using this data, the oceanographers make recommendations on plankton, temperature, altimetry, plankton concentrations, temperature frontal strength, floating algae index, and fishing for seven different species, including blue marlin, swordfish, mahi mahi, yellowfin, bigeye tuna, skipjack tuna, and wahoo. “Our commercial service, SeaStar Fisheries Information Service, has been enabling commercial fishermen to fish more effectively for over two decades,” says Prasad. But, “while developing new datasets for SiriusXM’s service, we tapped into entirely new data sources and developed improved algorithms—which will ultimately help commercial fishermen, too.”

Once the data is processed, it’s posted on Amazon Web Services, where SiriusXM picks it up and—you’ve got it—sends the data into space once again to be disseminated by its satellites. 

“SiriusXM transmits the data via satellite to its entire coverage area, which extends up to 150 miles beyond the U.S. coast line—well beyond cellular range,” says Dave Wasby, SiriusXM’s vice president of aviation, marine, and music for business. On their Garmin devices, fisherman can see, for example, concentrations of plankton, which attract hungry game fish, or sea surface temperature front strength, which can concentrate nutrients and attract both bait and game fish. 

Color codes are used for the seven species of fish, too, and update as new data is processed. 

On a recent charter, Weaver decided to target wahoo based off of information from the fish-mapping service. “I pointed my boat completely away from where all my other fellow captains were going,” he says. “And first thing in the morning we hooked into some tuna, and then a few hours later we got three wahoo—and then a couple hours after that we got covered up in wahoo.”

Weaver says that the maps are updated every several hours, which can mean the information is sometimes outdated. And fishing, of course, isn’t an exact science anyway: Ever-changing wind conditions, ocean currents, tide, and more can make fishing conditions extremely dynamic, and challenging for fisherman. But with information collected from space, fisherman can have an edge that can improve their excursions, saving them time, energy (as in, fuel), and frustration. 

“Ocean patterns are changing, and local knowledge is not always the best way to get the biggest catch,” says Prasad. But, “using our service, anglers know where to fish for their target species.” 

But the service doesn’t just help fisherman find the best catch: It can help the environment, too. “While the impact might not be as significant for leisure fishing, when it comes to commercial fishing, the implications are huge,” says Prasad. “We’re essentially helping to reduce the fishing industry’s carbon footprint while also making commercial fishing expeditions more profitable through fuel-cost savings.”