Fishing boats are coming under attack by an unlikely band of marauders bent on stealing their cargo.

Killer whales have reportedly been zeroing in on boats from the Gulf of Alaska to Aleutian Island to the Bering Sea — sometimes trailing them for days on end.

And when those nets are teeming with the day’s catch, they make their move, sawing through twine and feasting on the cargo.

In a letter to North Pacific Fisheries Management Council, fisherman Robert Hanson described a particularly precarious encounter, as reported in the Alaska Dispatch News.

The seasoned captain noted that he lost spent 4,000 gallons of gas trying to outrun a pod of whales last month — even drifting silently for 18 hours — before losing 12,000 pounds to his net-gnawing pursuers.

And the whales, which can grow up to 11 tons and race at speeds of 30 miles per hour, don’t respond to noisemakers either. In fact, the electronic horns designed to disperse them have become siren calls ... for supper.

“It became a dinner bell,” fishing boat operator Paul Clampitt told the National Post.

Prelude to a shakedown

A wild killer whale leaps into the air off the U.S. West Coast. (Photo: National Oceanic and Atmospheric Administration).

Killer whales, famed for their complex and patient hunting techniques, follow the beleaguered boats, encircling and harassing the vessel, much like a "motorcycle gang," fisherman John McHenry told the newspaper.

"You’d see two of them show up, and that’s the end of the trip. Pretty soon all 40 of them would be around you," he said.

The shakedowns have taken a heavy toll on the Alaskan fishing industry, with a University of Alaska study suggesting that commercial anglers lose as much as $1,000 per day to the pirating pods.

So what’s driving whales to a life of plunder and pillage? It’s possible they were inspired by sperm whales — behemoths that have been vexing fishing boats for decades.

The biggest factor, however, may not be a dearth of fish in the ocean, but rather an abundance of intelligence on the whale’s part.

Quite simply, they’re studying patterns in their environment.

As John Moran, a biologist with the National Oceanic and Atmospheric Administration (NOAA) explained to the Alaska Dispatch News, they’re adapting — and getting richly rewarded for it.

The orcas, he noted, distinguish between types of boats, even recognizing the drone of a hydraulic system, as it lowers nets into the water.

Who can resist the temptation for a little fast food? Especially when it’s being dangled, literally, in front of their noses.