ESSEX — The soft-shelled backbone of this town’s economy is under attack from an old enemy, with invasive species of crabs gobbling up clams throughout Essex Bay, experts say.
There may be two invasive species threatening the deep-fried favorite of Essex, the European green crabs and the Asian shore crabs. But Essex Shellfish Constable Billie Knovack says there is especially an uptick in European green crabs in Essex, and that means fewer for clammers to reel in.
“We have a green crab invasion,” he said earlier this month.
Usually, Knovack explained, the winter kills off the crab population. But warmer waters and warmer weather — which he attributed to climate change — means more time for the crabs to hunt Essex’s soft-shelled clams.
“It’s a much more opportune environment,” he said. “If you’re a crab, this is beautiful weather,” he said in 40-degree temperatures at the town landing earlier this month.
Knovack said there are no hard numbers as to the amount of European green crabs in the Essex River or Essex Bay, but the clams are disappearing. About two to three years ago, commercial clammers were meeting their annual 250-pound clam quota; now, clammers are catching about 150 pounds each annually, he said.
In addition, erosion is causing Crane Beach and Plum Island to draw more sand into Essex Bay, which may give more ground to clam flats. But the predatory crabs are still there, as well.
This threat is nothing new. The clam-hunting crab arrived on American shores in the 1880s said Alan Young, who holds a doctorate in biology and teaches at Salem State University.
While the green crab is the classic predator of shellfish and invertebrates, the Asian shore crab may also pose a threat to the seafood industry in Essex and beyond.