The Wrack

The Wrack is the Wells Reserve blog, our collective logbook on the web.

Impacts of green crab predation on soft-shell clams

Posted by | June 4, 2014 | Filed under: Observations

There has been a lot of buzz in the news lately about the impacts of the European Green Crab (Carcinus maenes) on the ecology and stability of New England salt marshes and the plants and animals that live there. One issue in particular is the effect of green crab predation on soft-shell clams (Mya arenaria) in the early stages of their development.

Dr. Brian Beal on a mud flatIf you've been following any of those stories the name Brian Beal should ring a bell. Dr. Beal is the director of research at the Downeast Institute and professor of marine ecology at the University of Maine at Machias. He has been working with soft-shell clams for years and is one of the leading scientists looking at the impacts of green crabs on soft-shell clam populations.

Clam PotsWe are working with Dr. Beal to examine the effects of predation on soft-shell clams in the intertidal mud flats as part of a larger project with sites throughout the Maine coast. At each site, 6 plots are established in the lower and upper intertidal zones. Each plot has 8 plant pots full of mud and seed clams buried flush with the sediment surface. Some pots are covered with mesh to protect the inhabitants from direct predation by green crabs, while others are left open to predation.

Sites within the reserve were chosen due to the amount of seeding done by the town in years past. From this study, we will better understand how predation by green crabs is affecting the survival rate of seeded clams for recreational harvest, results that may in turn help inform the town's seeding efforts. This project will run from June to October.

You can find a great article in Downeast magazine about the green crab and its impacts. You might also get a kick (and an education) out of the Attack of the Green Crabs video.

BealeJeremy Miller gives two thumbs up to working on the mud flats

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