Maine's mussel population could be in trouble. Wild shellfish harvesters are reporting few signs of life in areas that were once teeming with blue mussels.
Not a lot of research has been done into mussels, however, and nobody knows exactly why this is happening. But the comparative health of Maine's mussel farming industry maybe provide some clues as to what's hurting the wild population.
On Portland's working waterfront, mussel farmer Matt Moretti tests the equipment on his barge. He fires up the hydraulic generator that powers the on-board machinery used to process the mussels. Normally he would hope to be out in Casco Bay collecting produce by now, but the icy conditions have kept him frustrated shoreside for several days.
Weather aside, Moretti says business is good.
"We're growing every year and we plan to continue to grow while producing a quality product," he says.
Matt Moretti and his father, Gary, run Bangs Island Mussels. For more than four years they've been cultivating at a couple of sites out in Casco Bay. The mussels grow on lengths of rope hanging from rafts.
"So these are the grow-out ropes that we actually grow the mussels on," Matt Moretti says. "It's the Spanish style; we use thick rope with plastic pegs inserted into it about every foot. The pegs actually give the mussels support when they grow on the lines, so they don't fall off."
Nearly 3,000 of these 35-foot lines are suspended from seven rafts. They yield a 2,000-pound harvest between one and three times per week, typically.
In 2014, Bangs Island Mussels bought in around 200,000 pounds of mussels: the best year yet and a notable contrast to the apparent state of the wild mussel fishery.
"The decline is incredible, it's about 98 percent maybe, or 99 percent," says Phil Gray of Harpswell, who has been harvesting mussels since 1976. He says back then, mussels were plentiful and for years he made a good living harvesting by hand from a boat, raking them off the mussel beds with a pitchfork.
"We used skiffs, large open skiffs, and back then it wasn't uncommon to fill a skiff in an hour," he says.
For the last few years though, it's been a different story.
"Slowly getting out of the mussel business due to the green crabs having devoured all the mussels in the southern half of the state," Gray says.
As well as green crabs, he blames the overuse of dragger nets in past years for destroying many once-thriving mussel beds. It's probably worth noting that neither of these threats endanger mussel farmers such as the Morettis, whose growing ropes are suspended above the sea bed, safe from predators and dragnets.
And there are other theories for the mussel decline, notably climate change-related developments such as warming temperatures and ocean acidification. But it's all speculation right now, as not much research has been done into blue mussels. Maybe that's because they represent only a small fraction of Maine's seafood economy, with last year's landings totaling $2.3 million, compared with the $364 million lobster harvest.
One organization trying to collect more mussel data is Friends of Casco Bay. The environmental group is halfway through a survey of historically productive mussel beds. Over the last two summers, volunteers have examined 21 southern Maine sites. Research Associate Mike Doan says the results are disturbing.
"Of those 21 sites, 13 no longer had any blue mussels, and of the balance 3 areas were down to 5 percent of historical blue mussel populations," he says.
Also trying to fill the research gap is Cascade Sorte at the University of California, Irvine. With funding from the Massachusetts Sea Grant, she has been studying mussels in the Gulf of Maine for the past two years and is due to publish her paper later this year.
"What we've found so far is that for the sites that we have the most data, is that we're seeing declines in the mussel populations," she says.
Sorte says those declines average around 50 percent, but overall it's hard to get a clear picture of what's happening.
"I was really surprised when I started this project that there's no actually no frequent, consistent monitoring of the mussel populations in the Gulf of Maine," she says.
Sorte says one goal of her study is to collect a comprehensive set of data from 20 Gulf of Maine sites, from Quoddy Head to Cape Cod.
This way, she says, future surveys will have a reliable place to start from.