If you can’t beat’em, eat’em.

That was the gist of a working summit on green crabs held a couple of weeks ago in Portland. New Hampshire Sea Grant and Manomet, Inc., a local environmental consulting firm involved in sustainable seafood initiatives, co-sponsored the event.

The two-day event held at O’Maine Studios in Portland, brought together scientists, chefs, consumers and business people all interested in coming up with creative solutions to the problems posed by the invasive green crab, Carcinus maenus, that has wrecked havoc on native shellfish populations along the coast.

Green crabs showed up on the shores of North America in the early 1800s, having likely arrived in the ballast water of ships from Asia. However, their population didn’t soar until the 1950s, at which point they became ubiquitous along the coast from Nova Scotia to Virginia.

Their numbers grew unchecked because of a lack of natural predators and their amazing ability to survive under varying conditions. They can tolerate an unusually wide range of temperatures from 30 to 88-degrees F and can survive out of water for several days.

Add to that the fact that they have a ravenous appetite and you have a big problem. They especially love to eat shellfish, including some of our most valuable species like the native soft shell clam.

As Sarah Randall, associate director for the Downeast Institute, stated in her presentation, clam populations have declined 70 percent in the last decade and 99 percent of settling clams are being lost to predation, primarily by green crabs.

One green crab can consume 40 half-inch clams in a single day. That has a big impact on Maine’s shellfish industry, which, in a good year, is worth $15 million and supports more than 1,700 harvesters.

In addition to their consumption of clams, green crabs love to nibble shoreline and sub tidal grasses, using their sharp pincer claws to snip off salt marsh grasses along the water’s edge and eelgrass below the surface, both of which provide valuable habitat for numerous marine species along with helping to stabilize shorelines and add oxygen to the water.

Their numbers are only increasing as water in the Gulf of Maine warms and it is warming faster than 99 percent of the world’s oceans.

So, what do we do?

We’ve tried trapping them. Shellfish committees along the coast have done this. Schools have, too, including Brunswick High School as a part of their clam-growing project at Wharton Point. Citizen groups have also participated as far north as Nova Scotia, as presented by scientists from the Kejimkujik National Park.

As a result of trapping, clam populations have improved in some areas and those studying green crabs have been able to learn more about their population dynamics – things like how quickly they grow how large the population is, and when they reproduce.

But, trapping has hardly put a dent in the remaining green crab population. Others have tried excluding the green crabs from areas where clams are harvested to prevent them from munching baby clams.

They’ve fashioned cages and nets over areas of mud or sand to keep the crabs out. These have certainly been successful, but it still doesn’t do anything to help the clams that live outside of the protected areas.

Oh, and then there’s what to do with all those green crabs you’ve caught. They make good fertilizer and they have also been used for bait.

But, none of those things make much money and people’s compost piles are only so big!

Enter food scientists, chefs, and economists to figure out new solutions. Representatives from the small non-profit Green Crab R&D presented their research on the umami quality of green crabs, describing their ability to amplify other flavors in a dish and to create a “long, pleasing flavor trail.”

Scientists from the University of Maine at Orono crafted a mechanical separator that produces green crab mince, which can be made into things like crab cakes and crab empanadas.

Several presenters drew from international examples like the Venetian soft-shell crab (moeche) fishery. The Venetian species, Carcinus aestuarii, is similar to the green crab and has been harvested for over 300 years from Venetian lagoons. Fishermen there are experts in detecting when these crabs are going to molt.

Jonathan Taggart, an art conservator from Georgetown, witnessed these techniques on a trip to Venice and has been working with scientists from Manomet and NH Sea Grant, as well as Green Crab R&D on identifying green crab molting cues.

They’ve been trapping hard shell green crabs and identifying which crabs are on the verge of molting and selling the resulting soft shell crabs to local restaurants. Brunswick’s Henry & Marty and Bath’s Salt Pine Social have sold out of these soft-shelled delicacies every time they are on the menu.

Other scientists focused on the nutritional benefits of green crabs. University of Maine’s Bouhee Kang showed how isolated green crab proteins could be used as nutritional supplements to modulate blood glucose levels – a potential benefit for diabetics. She also described their anti-oxidant properties that can help the body to stabilize damaging free radicals.

And green crabs aren’t just helpful for humans. Steve Jury from St. Joseph’s College fed green crab extract to horseshoe crabs after their blood had been harvested for the medical market and noted that they recovered much more quickly before they were released.

Now it was time to eat them.

O’Maine Studios has a demonstration kitchen aptly set up for two star chefs. Ali Waks-Adams, executive chef at The Brunswick Inn and owner of Butter & Salt Pop Up put live crabs into a batter and let them crawl around and eat it before frying them up – the batter flavored them from the inside out.

When referring to her interest in green crabs, she said, “In the chef world, everyone wants to know what’s new and hot. The thing is in New England we’ve been doing it first.”

Other tasty delights included green crab-stuffed arancini made by Matt Louis, owner of Moxy and The Franklin Oyster House in Portsmouth, New Hampshire.

The second day of the event featured students from the West Bath Elementary, who presented their community outreach on green crabs, and breakout groups who dove deeper into the themes presented on day one.

There was certainly no lack of good ideas about how to make use of this growing pesky population.

But, as Brian Beale, director of research at the Downeast Institute said, “We can eat them, but we can’t eat them to death. We can trap them, but we can’t trap them to death. We need to adapt.”

He pointed out the importance of not only looking for ways to utilize green crabs, but also of protecting and enhancing soft-shell clam populations. Clam farming is one way to do this and could be done on a municipal scale along the coast.

He also suggested setting an upper-size limit for clams, much like that for lobsters, that would allow the larger ones to stay in the population as broodstock and provide valuable seed for the next generation.

Gabriela Bradt, a scientist from NH Sea Grant, made the argument that while the lobster industry is booming now, with rising ocean temperature there is a very real possibility that lobsters will move to cooler, northern waters and there should be an alternative fishery in its place.

Why not green crabs?

When addressing an ecological problem, you have to consider the whole ecosystem – not just the green crab, but also the clams, eelgrass, water temperature, and the people involved, as well. This workshop served to begin to make those valuable connections across species and specialties that will hopefully lead to some creative and tasty solutions.

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