By KELLY DICKERSON Business Insider

Monster shrimp, some up to the length of a man’s forearm, are invading U.S. waters.

Asian tiger shrimp have spread from North Carolina to Texas along the U.S. coast, but no one seems to know how they ended up in the U.S. in the first place.

They are originally natives to Indo-Pacific, Asian, and Australian waters.

The shrimp may have escaped aquaculture facilities in the U.S. or Caribbean, or maybe even drifted in on ocean currents from the Caribbean or even as far away as west Africa.

The shrimp first showed up in 1988, according to the National Oceanic and Atmospheric Administration (NOAA), and were linked to a South Carolina aquaculture facility where some 2,000 animals were accidentally released. Scientists aren’t yet calling Asian tiger shrimp an “established” species since its still unclear if they are successfully breeding or just drifting in on currents.

Check out the video on the Business Insider website from the Wall Street Journal to get a better sense of the size of these monsters.

There are signs they’ve started breeding: Scientists have seen young Asian tiger shrimp in the marshes of Mobile Bay in Alabama, suggesting the species is reproducing locally.

The presence of these invaders has been reported for over a decade, but in recent years the reports have noticeably increased.

Pam Fuller, the USGS biologist in charge of the Nonindigenous Aquatic Species database said they have confirmed nearly a tenfold increase in reports of Asian tiger shrimp in 2011.

“And they are probably even more prevalent than reports suggest, because the more fisherman and other locals become accustomed to seeing them, the less likely they are to report them,” Fuller said to NOAA.

Asian tiger shrimp are predators, unlike the native scavenging U.S. shrimp. They eat crabs, clams, and even other shrimp. Researchers are racing to discover how this invasive species could impact native coastal ecosystems.

The native shrimp are much smaller.

These giant shrimp are totally edible, and supposedly taste good! They’re delicious in butter sauce just like other shrimp.

Now that the native white shrimp season is about to start, NOAA is asking fishermen to log where they find the invading species, how many they catch, and if possible, to send in pictures.

The image attached shows where they’ve found the shrimp so far. They are concentrated along the coast. And check out this interactive map from the USGS to see how they’ve spread.

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