Growing Oysters as Ocean Chemistry Changes
Mook Sea Farm in Maine Drives R&D
Nicholas Sullivan
Mook Sea Farm on the Damariscotta River in Walpole, Maine is one of the largest and most innovative oyster farms on the East Coast. Started by Bill Mook in 1985, the farm produces 5–7 million oysters a year for the half-shell market (branded as Moondancers and Mookie Blues), as well as 120 million disease-resistant seed for other growers from Maine to Carolinas. Clearly, Mook has mastered the art of spawning and producing oysters. Now, Mook is grappling with protecting those oysters against the effects of climate change.
In 2009, Mook Sea Farm experienced serious oyster-larvae production problems, which it attributed to ocean (and coastal) acidification. As larvae “set” and transition to juveniles, lack of calcium means less predictable shell growth and hardening. A similar acidification issue had affect oyster larvae on the West Coast in 2007–08. The drivers of changes in water chemistry on the East and West Coast were different, but both are linked to human activity.
“Our hatchery was quite severely impacted, and it cost us hundreds of thousands of dollars,” says Bill Mook, founder and president. “It’s a really, really anxiety-provoking situation, and it puts a lot of stress on, not only the owners, but the employees and everybody else whose livelihood depends on that water quality.”
In 2013, Mook teamed up with fisherman-turned-oceanographer Joe Salisbury of the University of New Hampshire. Salisbury and installed in the hatchery sophisticated technology that Mook calls “the black box” — sensors housed inside a heavy black plastic case the size of a breadbox that measure carbon dioxide and alkalinity, or the capacity of the water to buffer against increases in acidity. The “black box” was developed with funding from the NOAA’s Ocean Acidification Program and Integrated Ocean Observing System.
To counteract the lack of calcium, Mook began buffering the water in his hatchery with sodium carbonate to raise the pH to optimal levels. The effect of the buffering was immediate, resulting in better larval production than ever before. This clear cause and effect made Mook realize that climate change was costing the oyster farm in multiple ways and that those costs were increasing. For example, New England has recently been subject to increasingly heavy rainfall events, which has resulted in multi-day bed closures that impact harvest and sales of market oysters. Warming waters, caused in part by the infusion of Arctic ice melt into the Labrador Current that has long been a factor in the Gulf of Maine’s marine productivity, has led to an increase in pathogens. The decline in primary productivity, or the phytoplankton that oysters feed on, is another major alarm bell.
Right now, the problems of acidification mostly impact the hatchery. Adult, grow-out oysters make their shells out of a different form of calcium carbonate. That said, the real effects of acidification on mature oysters is unknown, with more research on water chemistry and grow cycles needed.
Run-off and harvest closures pose an equally serious challenge. The Damariscotta River watershed covers 103 square miles — essentially a huge estuary that flushes 30 billion gallons of water in and out with every tide. Every time two inches of rain or more falls in less than 24 hours, the Department of Marine Resources closes down shellfish harvesting in the watershed until water tests come back clean. This multi-day event sidelines workers and prevents product from going to market. “We recently had three closures in two months,” says Mook. “That’s about $30,000 in lost sales.”
In 2018, Mook persuaded seven growers to form the Shellfish Growers Climate Coalition, under the umbrella of The Nature Conservancy. It now has 120 members from 20 states and is active in lobbying for climate-change legislation. Of course, there are a lot of climate-change lobbying groups. What’s significant about Mook is how he is investing to reshape his production facilities to build business resilience against climate change. The centerpiece of his strategy is a new indoor facility with large tanks that can keep thousands of oysters alive during river closures. Mook’s new $2 million, 9,000-square-foot facility is essentially a land-based aquaculture farm.
When there’s a threat of heavy rains, such as in the aftermath of Hurricane Florence in 2018, Mook moves cages with tens of thousands of market oysters from the river into four tanks with roughly 26,000-gallon capacities. Filtered and UV-irradiated water flows down through triple-stacked product containers, flushing them free of particles. A recirculation system can keep the water fresh for several days without sucking in river water. “During the last closure we shipped about 20,000 oysters that we wouldn’t normally have shipped during a closure,” says Mook. “It’s hard to get that business back when sales are interrupted.” The roof of the facility has 282 solar panels to help offset what is an electricity-intensive operation.
Climate change is bringing other challenges. Vibrio, a bacteria that can be toxic for humans, has been moving north as the water warms. Down the line, if vibrio shuts down the Damariscotta’s oyster harvest for an extended period, Mook says he’ll decontaminate them in his new indoor facility. He’ll need FDA approval for that — but he believes he’ll get it. Mook can set the tank water at an optimum temperature — warm enough that the oysters are still metabolically active, but cold enough so that the vibrio reproduction rates are dramatically decreased.
Overall, Mook Sea Farm is a leader in research and development. “Part of our business model is to really attack biological problems head on,” says Mook. “That’s not necessarily cheap, but it increases your dependability as you go. That’s something that’s led us to really making a commitment to R&D.” Mook continues to invest in developing hatchery technologies, especially as it plans to add scallops and surf clams as new hatchery crops.
In addition to its climate-resiliency efforts, Mook Sea Farm has a proprietary system for growing microalgae for the hatchery using fermentation technology, a major biology project. The company grows 99.5 percent of its microalgae using sugar as fuel for cultures in large centrifuges. This dense, rich feed — “green gold” — which Mook is selling to other growers, is less expensive to grow and more nutritious than traditional “white-light” microalgae production. “If you think of the hatchery as the engine that drives our business, which it is, the microalgae are the fuel that runs our engines,” says Mook.
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Nicholas Sullivan is a Senior Fellow at the Fletcher School’s (Tufts) Center for Emerging Market Enterprises and a writer for Oliver Wyman, a global consulting firm. He is the author of two books: You Can Hear Me Now: How Microloans and Cell Phones Are Connecting the World’s Poor to the Global Economy and Money, Real Quick: Kenya’s Mobile-Money Innovation. He was previously publisher of Innovations: Technology/Governance/Globalization (MIT Press). Sullivan has also been a Visiting Scholar at MIT’s Legatum Center for Development & Entrepreneurship.
He is now working on a Fishing 4.0 project, focusing on innovations in hunting, harvesting, and farming fish, for which he received a 2019 Bellagio Fellowship from the Rockefeller Foundation.
