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Four Mook Sea Farm workers began their first oyster harvest of the day on Sept. 22 later than usual, given the morning’s torrential rain and lightning. On some days when there is a downpour a state alert shuts down oyster harvesting until water purity can be tested, as more runoff into rivers can result in unhealthy levels of bacteria in the shellfish, which are often eaten raw.

But on this day the workers were free to pull up floating oyster cages from the Damariscotta River, near South Bristol. Under overcast skies, they yanked out six muddy bags from each cage filled with hundreds of oysters and dumped them into large bins on the boat. In one hour they harvested nearly 50,000 oysters to take back to the warehouse to process and deliver to local restaurants.

Scientists and oyster farmers have seen more intense storms over time, which have caused frequent shutdowns. Oyster farmers in Maine have also had to contend with another result of climate change: ocean acidification. Studies show that the change in the chemistry of seawater, caused by the ocean absorbing more carbon dioxide, can slow the growth of oyster larvae shells — and can sometimes even dissolve them.

The environmental changes have threatened the livelihoods of oyster farmers who depend on clean water. But in Maine, the farmers have fought back. They have come up with solutions to improve the marine environment, hired their own researchers to understand what is happening, shifted to using renewable energy and limited their use of plastics, and turned to policy work at the state and regional level to build climate resilience.

Their efforts appear to be paying off. In 2021 the state’s oyster harvest was the largest in history, growing by more than 50 percent over the previous year, according to the Maine Department of Marine Resources. The oyster business was also the most valuable it has ever been at more than $10 million, making it the fourth-most valuable marine resource in Maine. It was worth less than $1.3 million just a decade ago.

Clockwise from left: Mook Sea Farm worker Patrick Stafford (left) leans over the side of the boat to reach a floating oyster cage in the Damariscotta River in South Bristol, Maine on Thursday Sept. 22, 2022. At right is Patrick Williams; Mike Sheehan and Jake Kollman head out to one of Mook Sea Farm’s grids looking for floating oyster cages in need of repairs; Williams (left) and Stafford (right) pull bags of oysters from cages and load them into large bins on a boat in the Damariscotta River. Credit: Linda Coan O’Kresik / BDN

Some fishermen have worried that oyster farms will limit their access to fishing grounds. But others point out that oysters add ecological value for many marine species, as oysters filter and clean the surrounding water. Oysters are farmed in salty or brackish coastal waters, as there are not enough naturally occuring oysters in the colder waters on the outer coast to sustain a wild oyster fishery in Maine.

Bill Mook, the owner of Mook Sea Farm who is considered a pioneer in Maine’s aquaculture industry, is hopeful about where the industry is headed and pleased to see it bring in many young people in recent years. Mook is also a founder of the Shellfish Growers Climate Coalition, which is made up of more than 250 shellfish businesses from across the United States and Canada that aim to protect water.

“It’s an industry filled with environmental advocates who are advocating for policies that are going to keep their livelihoods going, and that’s a powerful thing,” Mook said.

Oyster farmers see the effects of a changing climate in their everyday work. In 2009, Mook noticed it was taking longer for oyster larvae to grow, leading to losses. It struck him then that the tiny, free-swimming larvae were taking up too much energy to filter feed and weren’t able to develop without adequate nutrition, due to changes in water chemistry.

Oyster larvae need to grow to be able to metamorphose — attach to a solid structure and grow their shell. The acidification of coastal waters resulted in a lower seawater pH that prevented the oysters from thriving.

Clockwise from left: Mike Sheehan sorts oysters by size and quality at Mook Sea Farm in South Bristol, Maine on Sept. 22, 2022; Workers are busy cleaning and sorting oysters; Steve Zimmerman, COO of Mook Sea Farm, holds oyster seeds in his hand. The oyster farm and hatchery on the Damariscotta River in South Bristol, Maine uses science and technology to produce oysters sustainably. Credit: Linda Coan O’Kresik / BDN

To combat both the frequent shutdowns from storms and the ramifications of acidification, Mook set up a shoreside warehouse that can hold up to half a million oysters at a time. The large bins of oysters are supplied through a piping system with 100,000 gallons of seawater, which is chemically buffered to higher pH levels. Even with natural interruptions, Mook is able to continue to raise and sell oysters through his land operation.

Founded in 1985, Mook Sea Farm prides itself on using science and technology to breed and raise oysters sustainably. Mook, trained in marine science, also owns a hatchery, housed in a separate building, that produces and sells oyster seed, or baby oysters, to more than 30 farms. Hatcheries like Mook’s are important for the oyster industry, especially in Maine where there is no wild set of oysters.

In addition to building up his infrastructure and ensuring other farms have the baby oysters they need to sustain their businesses, six years ago Mook also employed a researcher, Meredith White, to make his business more climate resilient. White has worked with other researchers to deepen the understanding of regional coastal acidification.

Bill Mook, the owner of Mook Sea Farm in South Bristol, and Steve Zimmerman, the chief operating officer of the oyster farm, are pictured at New York City’s Oyster Bash in September 2019. Credit: Courtesy of Bill Mook

Some fishermen have shifted to oyster farming because they can control many production variables given that the industry doesn’t depend on a wild population. That’s one reason why David Cheney switched to oyster aquaculture, he said, after seeing diminishing clam harvests and rising costs of operation in the lobster industry. He founded Johns River Oyster in New Harbor in 2007 and has gained fame from seeing his oysters served up at the always-booked Lost Kitchen restaurant in Freedom.

Cheney and others said they enjoy raising oysters because of their sustainability.

“The industry is dependent on hatcheries to produce seed and isn’t taking from the natural production of oysters,” said Chris Davis, the executive director of the Maine Aquaculture Innovation Center, which was established by the Maine Legislature in 1988 to research and develop environmentally sustainable aquaculture practices. In addition, “there’s no discharge into the water column from oyster aquaculture.”

Oysters, like other shellfish, take in nutrients by pumping in water. They capture particles such as plankton, algae, sediments and other contaminants, which they digest and filter. Through this process, oysters also sequester carbon to build their shells, said Robert Steneck, a professor of oceanography and marine biology at the University of Maine.

Clockwise from left: Steve Zimmerman, COO of Mook Sea Farm, explains that algae is grown in the hatchery as a food source for the oysters; Zimmerman explains how the staff use the setting system in the hatchery to help larvae attach to a substrate and form their shell; Mook Sea Farm, an oyster farm and hatchery on the Damariscotta River in South Bristol, Maine, uses science and technology to produce oysters sustainably. Credit: Linda Coan O’Kresik / BDN

Davis also founded Pemaquid Oyster Company in Bristol in 1986, making it — along with Mook Sea Farm — among the first oyster farms in the state. Sourcing its oyster seeds from local hatcheries, the company sells most of its oysters to local restaurants in Maine and also ships them to major cities on the East Coast, including New York, Boston and Philadelphia.

Oyster farmers pay close attention to climate issues because they have been gathering water quality data since the 1980s to ensure they are producing a high-quality product, Davis said.

Davis has prioritized involving the community in his work by helping to organize the Pemaquid Oyster Festival — complete with an oyster shucking contest — since 2001 in Damariscotta. Over the past 20 years, the oyster festival has raised more than $175,000 to donate to 50 education, research and sustainability projects, Davis said.

The festival really began as a big party and a way to sell oysters, but, after the first year, it grew into a nonprofit to focus on environmental concerns on the river and the sustainability of the industry, Davis said.

Some of the funds went to area elementary and middle schools that teach courses on oysters, conservation groups protecting the Damariscotta estuary, a fish ladder, and a sewage pump-out station for boats to dispose of waste and prevent direct discharge into the estuary.

Oyster farms are also turning to renewable energy to reduce their carbon footprint.

In 2019, Brunswick-based Ferda Farms set up a work float with processing machinery to meet increasing consumer demands. To power the work float, he chose to go solar. A fuel-power generator would have cost nearly $1,000, but Max Burtis opted for solar components instead for $3,500. While it was a higher upfront cost, solar proved to be a more affordable long-term option in line with his vision for sustainability, he said.

Ferda Farms was originally founded by three high school seniors — Max Burtis, Max Freedman and Samuel Dorval — in 2018. The high school friends grew up digging clams. Currently, only Max Burtis and his father, Chris Burtis, a commercial fisherman, run the company.

From left to right, Max Burtis, Samuel Dorval and Max Freedman — the three high schoolers who founded Ferda Farms in Brunswick — are getting ready to leave the dock to grade baby oysters on Oct. 31, 2018. Credit: Courtesy of Kelli Park

“I think it’s feasible to do solar for your small operations, off-grid, offshore, and it’s not terribly expensive or difficult,” Max Burtis said, and “it’s reliable.”

Burtis said he was inspired by the Mere Point Oyster Company in Brunswick, which went solar two years before them. Burtis has since helped other small farms explore and set up solar power.

The Pemaquid Oyster Company is also exploring ways to make its operations more sustainable and is looking into installing solar panels this fall to offset energy use, Davis said.

There is an ongoing effort to reduce the use of plastic and styrofoam in the industry, according to Afton Vigue, the outreach and development specialist for the Maine Aquaculture Association, which represents the industry.

The fishing industry has “some of the best innovators,” Vigue said. “They’ve been evolving their fishing strategies, gear, and where and what they fish for years.”

For instance, Ocean Farm Supply, founded by Eric Oransky and Erin Adams of Maine Ocean Farms in Freeport, has created a biodegradable and compostable harvest bag made of beechwood cellulose fibers.

Similarly, Abigail Barrows, an ocean plastics researcher and the owner of Long Cove Sea Farm in Deer Isle, has been experimenting with oyster bags made of wood with stainless steel or aluminum mesh.

Burtis, with Ferda Farms, has switched to biodegradable bags for market produce and is also looking into options to fund the electrification of boats on the farm.

“We haven’t found a good solution to go plastic free yet,” he said. “That’s one of our biggest issues.”

Farmers everywhere can benefit from learning from one another about how to tackle environmental challenges, which is why the Maine Aquaculture Innovation Center will soon announce a new program to facilitate technological exchange between aquaculturists, Davis said. The program will allow farmers to learn different techniques from aquaculture farms across North America, which they can then share with other Maine growers.

Many oyster business owners are highly educated individuals with specialized degrees, said Keri Kaczor, the environmental literacy and workforce development program manager at Maine Sea Grant, a federal-state partnership to support the coastal environment and economy, based at the University of Maine.

“There are real trailblazers in our oyster industry in Maine,” Kaczor said. “You don’t always see such a marriage between science and industry.”

Mehr Sher is a Report for America corps member. Additional support for this reporting is provided by the Unity Foundation and donations by Bangor Daily News readers.

Mehr Sher reports on the Maine environment. She is a Report for America corps member. Additional support for her reporting is provided by the Unity Foundation and donations by BDN readers.