WILMINGTON, N.C. -- Grab a fork and some cocktail sauce. A LOT of cocktail sauce. North Carolina waters may be on the brink of a population explosion of an invasive species that is troubling, tasty and titanic.
Well, titanic for a shrimp.
There has been an ominous spike in catches here and across the Southeast of Asian tiger shrimp, a Pacific and Indian Ocean species that can grow more than a foot long and weigh nearly a pound.
Throughout the shrimp’s new range along the Gulf Coast and South Atlantic, reports increased from 32 in 2010 to 331 last year, according to the U.S. Geological Survey.
“We’ve been monitoring it for some time, and in 2011 we saw several major increases in the Southeast,” said James Morris, an ecologist who studies invasive species for the National Oceanic and Atmospheric Administration’s National Centers for Coastal Ocean Science in Beaufort. “When you see a sharp jump like that, it’s a first alarm that we may be seeing an invasion.”
North Carolina’s coast is basically the northern extreme of the tiger shrimp’s invasive range. They can’t live in water that’s cooler than about 55 degrees, Morris said.
The first of the oversized crustaceans caught here was landed in 2006 in the Pamlico Sound, according to U.S. Geological Survey records. Since then, only a handful have been found. But the total jumped from two reported in 2010 to 19 in 2011, adding to the regional spike.
The jump in reports around the Southeast has triggered another wave of alarmed news accounts that sometimes refer to the shrimp as not just giants, but cannibal giants.
Which is true in the sense that they eat smaller shrimp. But so do native shrimp and most species of fish, Morris said.
“That’s fine, though, because if calling them cannibals puts more attention on the problem, that’s a good thing,” he said. “The basic point is that invasive species are bad. We may be on the verge of seeing a big increase in this species in the Southeast and Gulf coast, and we don’t know what the long-term impacts of that would be.”
What would happen?
The question that concerns researchers such as Morris is what the effects would be if the population does get large.
Like its smaller cousins, the shrimp is a bottom feeder, nibbling detritus, small plants and animals. The giant ones, though, can eat larger creatures and tend to be more carnivorous than native shrimp.
The extraordinary size of the tiger shrimp is one of the biggest wild cards in trying to predict its effect. There is nothing else quite like it in the area.
It’s possible that if populations zoom, the tiger shrimp could turn out to be a better competitor for food and would edge native shrimp and fish species. If it has a big edge and takes advantage, it could become dominant in the manner of invasive organisms such as kudzu and zebra mussels.
For now, though, researchers are tracking the population size and waiting to see what will happen.
Fisheries officials are also in wait-and-see mode. They are helping by passing to Morris all information about tiger shrimp that are caught.
It’s too early for alarm, but not for concern, said a spokeswoman for the N.C. Division of Marine Fisheries.
“Any time there is a new invasive species showing up in our waters we consider that a potential problem, and you watch it closely,” said Patricia Smith. “Right now that’s where we are with this one.”
How do they taste?
It sounds humorous, but if the population does soar, sautéing could be at least part of the solution.
That’s one strategy that’s being tried with the lionfish that have moved into our coastal waters. They are tasty, at least once you’ve sheered off their poisonous spines.
The giant shrimp may be an even better candidate, as they have an established culinary reputation: They are popular in Asia and elsewhere in the world, and often are sold under the name Giant Tiger Prawns.
They can be a little tougher than properly cooked native North Carolina shrimp, but they undeniably have a lot more meat.
Not that Morris, who is at the end of a long chain of custody, from shrimpers to fisheries officials, has had a chance to tuck into any.
He laughed at the idea.
“When I get ’em, they’ve usually been in someone’s freezer awhile,” he said.