Join us November 29th to discuss green crab trapping & rebounding clam populations!




Is heavy commercial green crab trapping helping create a bumper soft-shell clam harvest? Could this actually be true, or are we deluding ourselves? Something big and mysterious is going on in Clamtown, as Ipswich, Massachusetts used to be known. (The area is still a major shellfish producer today.) Here, along the middle of the biggest salt marsh in New England, the green crab population has been going down in recent years (according to monitoring by Alyssa Novak and Peter Phippen), quite possibly because of heavy commercial crab trapping.

At the same time, the soft-shell clam harvest is going way up. According to the Ipswich shellfish constable, Scott LaPreste, 2018 is the best soft-shell clam harvest in a generation. Local soft-shell clams are now so plentiful that the individual harvest quotas have been raised to 300 lbs. per clammer per day, which is more than all but the most experienced and determined clammers can handle. The big question is whether these two local trends – the crabs going DOWN, the clams going UP – are connected. The trappers think so. The biggest green crab trapper and wholesaler in the area (and possibly in North America), Adam Smith, believes that he and other trappers have been putting enough downward population pressure on the crabs that more clams have survived.

Not so fast, say scientists and administrators, who want to see much more data, and who have other plausible explanations for the bumper clam harvests. Most green crab trapping programs have failed, because of the crabs’ phenomenal ability to reproduce and repopulate within a single calendar year. So the scientists are skeptical.

But nobody wants to ignore or dismiss what could be a breakthrough success, since it was the crabs’ threat to commercial clamming that raised the alarms in the first place. And at the very least, this curious situation is worth exploring. Just 100 miles to the north of Ipswich, around Freeport, Maine, the green crabs have overrun the clam flats, and the soft-shell clam harvests are down by 70%. What accounts for the differences?

Everyone with a first-hand working knowledge of the green crab phenomenon is invited to a working lunch to take a good hard look at the numbers, examine and debate our assumptions and methodologies, and discuss future grant opportunities and projects.

Regional green crab working lunch meeting:

November 29, 2018 * 11:00 AM - 3:00 PM * Ipswich Town Hall Meeting Room A

This informal event is free (including lunch) and open to anyone who wants to attend. Somewhere between 20 and 50 scientists, shellfish officials, trappers, and activists are expected to attend this meeting.

We’ll meet and schmooze. We’ll decipher the numbers. We’ll have a friendly debate about the effectiveness of trapping.  We’ll ask each other, what can we do to better monitor the crucial interface between the crabs and their prey. And we will ask: If we can agree on common standards for future monitoring, might opportunities arise for coordinated studies in dispersed geographical areas? These large studies have never been done before, and they are way overdue.

Mary Parks