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Maine’s growing aquaculture businesses may benefit from warming waters along the state’s coastline, but the overall impact of climate change presents a mixed bag for the industry, according to experts.
Unless those impacts are boiled down to the increasing threat of severe weather, in which case there’s no upside for anybody.
Seafood growers from around the state gathered Thursday at Maine Maritime Academy in Castine for a summit at the Maine Aquaculture Innovation Center to learn about changes and growth in the industry, the economic impact of which has grown over the past 15-plus years from $50 million to nearly $140 million, according to industry officials.
Much of that growth has been from farmed oysters and seaweed, which have benefited from warming waters in the Gulf of Maine while other species such as mussels and softshell clams — farmed or otherwise — have not fared well with the higher temperatures. Along with the warmer water, which has brought predators such as green crabs to Maine’s clam flats, climate change has made the gulf slightly more acidic, which has harmed thin-shelled clams and mussels.
But aquaculture operations of all stripes are facing challenges from climate change, officials at the summit said. As conditions continue to shift, seafood growers will have to become more resilient to storms and adapt to more routine environmental changes in order to stay afloat, they said.
“We should be thinking about this as regime change,” not just warming waters, said Damian Brady, a professor of oceanography and acting director at University of Maine’s Darling Marine Center.
The state will see more sou’easters over time, he said, just like the two back-to-back storms that pounded Maine’s coast a year ago with southeastern winds and caused widespread damage to the working waterfront and other wooden piers along the entire coast.
Aquaculture lease sites in Maine often are in relatively sheltered areas such as tidal rivers or protected bays, Brady said, and so were less exposed to the wind and waves of last year’s storms than the commercial fishing piers that tend to be on peninsulas closer to the open ocean.
But aquaculture sites are not immune from storm damage. Finfish pens such as those used by Cooke Aquaculture in Hancock and Washington counties, and other sites from Penobscot Bay to the east tend to be more exposed to wind and waves than sites located up tidal rivers in the midcoast.
But even upriver aquaculture sites can face disruptions from storms such as displaced moorings, broken or tangled ropes or snarls of farmed seaweed.
For that reason, seafood growers are looking to beef up their equipment and switch to more robust lines and cages and, in some cases, to spread out their equipment within their lease areas to avoid tangles.
“The top priority is development of storm-resistant gear,” said Emily Whitmore, a social scientist with the aquaculture innovation center who has polled seafood growers about their concerns and ideas.
Brady said the lingering effects of storms caused by infusions of rainwater or sediment churned up in the water also can have an impact. Acadia Sea Farms documented water conditions at its oyster grow site in Trenton and found “massive, massive resuspension” of sediment in the water column that took a couple of days to resettle, he said.
To help growers anticipate these changes, Thursday’s summit featured several sessions that touched upon how to make physical infrastructure less vulnerable to changing conditions, and how those changes are having a direct effect on the species they are trying to cultivate, whether it might be algae outbreaks or changes in spawning behavior.
Despite the challenges climate change poses for Maine seafood growers, Brady is optimistic the industry will adapt. Aquaculture has always required a lot of experimentation even under the traditional suite of conditions years ago, and the changes growers are seeing now just means they will have to continue experimenting to see what works.
“Aquaculturists are super resilient, super innovative and very passionate about this,” Brady said. “They keep working at it and tweaking it and tweaking it.”
