May 21, 2018
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Harpswell closes 15 acres of mud flats in bid to wipe out predatory crabs, worms devouring shellfish

Troy R. Bennett | BDN
Troy R. Bennett | BDN
A green crab in in Maquoit Bay in this August 2013 file photo
By Peter L. McGuire, The Forecaster

HARPSWELL, Maine — Selectmen have approved closing almost 15 acres at the mouth of Strawberry Creek to worm and clam harvesters to conduct a series of experiments aimed at removing predators causing havoc in the local shellfish industry.

The project, recently approved by the Maine Department of Marine Resources, is the result of legislation passed earlier this year that gives towns the ability to restrict bloodworm harvesters from working in specific areas reserved for conservation.

According to Darcie Couture, the town’s marine resource coordinator, Harpswell intends to set up at least 10 green crab traps along the southern boundary of the conservation area. Volunteers will check them twice a week to measure the size, weight and sex of the crabs collected.

The study will last from July 1 through the end of December.

There is some indication that the brutally cold winter may have caused a mass die-off of green crabs in Casco Bay, but Couture said it is too early to tell what the impact has been. She said anecdotal accounts differ widely as to whether the crabs are all dead or hordes of them are waiting to emerge at the height of summer.

“Once we get to the warmest period of the year, then we’ll know, ‘alright, are we going to see more crabs moving in or are we past it,'” Couture said.

The pilot project also hopes to completely remove milky ribbon worms from the area. The worms prey on clams by injecting tooth-like proboscis through their shells and digesting them from the inside.

Unlike crabs, the only environmentally safe way to remove worms is by hand, Couture said, meaning significant numbers of volunteers are needed to clear them out of the flats.

There are no good answers as to why the worms appear to be such a severe problem in Harpswell, but it might have to do with the town’s diverse ecosystems, Couture said.

“It could just be that Harpswell happens to have one of the more favorable environments for the milky ribbon worms and that’s why they’re seeing more there, but we’re not sure,” she said.

Volunteers also will measure acidity levels in the sediment and water temperature, and establish a site in the area to assess the impact on clam survival during the season.

Data collected from the project will be analyzed in a report and sent to DMR.

The pilot project follows an attempt last year to legislate restrictions on bloodworm harvesters, who have come into conflict with clammers in recent years over access to the area’s clam flats.

A bill sponsored by Sen. Stan Gerzofsky, D-Brunswick, last year would have allowed allow towns to close off mud flats to worm harvesters, but it was heavily amended at the urging of DMR.

The final law allowed only a handful of towns to request permission from the state to temporarily close off an area that is less than 10 percent of the town’s total intertidal acreage for predator control and conservation measures.


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