ELLSWORTH, Maine — November 18, 2013 — Green crabs have been found in coastal waters off Maine for around a hundred years, but it’s only in the past few that they’ve drawn the ire and attention of fishermen and scientists in the state.
Officials have been receiving reports from fishermen that the coastal population of the crabs, which migrated to North America from Europe with shipping traffic in the late 1800s, has shot up, according to Kohl Kanwit of the Maine Department of Marine Resources — and eelgrass beds and soft-shell crabs have been paying the price.
That’s why, in late August, DMR organized a one-day, coast-wide survey to try to get a handle on exactly how many green crabs might be skittering around the shallow waters off Maine’s beaches and marshlands.
Kanwit said only preliminary results from the survey are available, but even when all the information is in, it will be hard to put into context. The department has not done a green crab survey for at least 20 years, and the survey methods used back then may not be the same as those used in August, when lobster traps and some specifically designed for green crabs were used. But she said that anecdotally, there is consensus among fishermen and marine researchers that “green crabs have increased appreciably in the last two years” between Biddeford and Frenchman Bay.
“One of the objectives of the study was increasing awareness of the issue of green crabs coast-wide, and that was achieved,” Kanwit said in an email.
Preliminary results from the survey indicate that 94 percent of the 221 traps deployed between Biddeford and Lubec on Aug. 28 had at least one crab in them. Seventy-five percent had at least 20 crabs. One trap caught 575 green crabs while the highest catch rate was in Searsport, which had an average of 191 crabs per trap.
Kanwit said DMR hopes to release the complete data from the survey at a Dec. 16 conference at University of Maine in Orono. The conference is free and open to the public but preregistration is required.