Meredith White, head of research and development for Mook Sea Farm, discusses the company’s oyster hatchery and grow-out operation in the Damariscotta River estuary during a presentation at the University of Maine Darling Marine Center in Walpole on October 12. (Photo by Brian P. D. Hannon)
Meredith White, head of research and development for Mook Sea Farm, discusses the company’s oyster hatchery and grow-out operation in the Damariscotta River estuary during a presentation at the University of Maine Darling Marine Center in Walpole on October 12. (Photo by Brian P. D. Hannon)
While bait shortfalls and regulation changes are among the most frequently debated topics within Maine’s fishing community, aquaculture continues to draw serious discussion as the threat of climate change looms over the seafood industry. Among those interested in exploring scientific solutions, Meredith White hopes to steer the conversation toward oysters.

The head of research and development at Mook Sea Farm, White described the company’s scientific and manufacturing efforts during a presentation at the University of Maine Darling Marine Center in Walpole on October 12.

Located in the Damariscotta River estuary, Mook Sea Farm grows American oysters in three sizes, including the “Wiley Point” variety at 3.5 to more than 4 inches, “Pemaquid Points” between 3 and 3.5 inches, and the “Wiley Petites” at less than 3 inches.

White explained the company, named for owner Bill Mook, operates two separate parts: a hatchery and a “grow-out.”

The hatchery pumps in Damariscotta River water, essentially ocean water, which is then filtered and UV-sterilized before heating to a desired temperature. This is considered a “semi-open system” because water is returned to the Damariscotta.

“The larvae and seed oysters are given the most optimal conditions possible, but still can be affected by dissolved contaminants in the ocean water that is pumped in,” White said. “So it is not 100-percent isolated from the ocean, but we do take steps to improve and control the water quality in this land-based hatchery.”

In the grow-out, seed oysters are provided food in the company’s newly enhanced facility until mature enough for sale. “Market-size oysters can be brought back into the semi-open tank system in the new building to avoid rainfall closures and hopefully, if our R&D pans out, to further ensure consumer safety.”

White, who holds a Ph.D. from the Massachusetts Institute of Technology/Woods Hole Oceanographic Institution Joint Program in Oceanography, explained Mook Sea Farm uses a unique “heterotrophic” method to produce algae, the food for oyster larvae and juveniles in the hatchery. The system — the only one of its kind, according to White — differs from the industry standard “phototrophic” process and reduces time, labor and electrical costs.

“Phototrophic production requires a lot of lights, which also produce heat, requiring air conditioning year-round. When Mook Sea Farm switched to heterotrophic production, electrical costs associated with algae production were reduced by 97 percent,” White explained. “Our heterotrophic cultures are more than 100 times more concentrated than phototrophic cultures, reducing the square footage of the hatchery that must be devoted to algae cultures and reducing the number of cultures that need to be tended to, reducing labor.”

She added that the process will also separate algae and larval production, which is a “big step forward for shellfish aquaculture.”

The company reached another milestone last month when the facility avoided a rainfall closure that lasted more than three days and affected much of the state. Rain can change water chemistry, and closures are normally mandated to ensure conditions have not been compromised in the closely regulated growing areas.

Shuttering a facility while safety tests are conducted directly affects the bottom line. “Each closure can cost us tens of thousands of dollars in lost sales,” she said.

Avoiding a temporary closure was a first for the company, as well as for Maine’s oyster industry, according to White.

“While other farmers were not able to harvest during the closure, we were able to ship oysters that had been moved to our holding room just prior to the closure, with a harvest date of the day they left the facility,” White said. “This is extremely significant for us because it saved us lost revenue during this particular closure, but it also starts to show our distributors that we can dependably provide them with oysters with a fresh harvest date even during extreme weather events.”

White described in technical terms the process through which Mook Sea Farm is working toward cultivation of oysters in a contained, scientific environment focused on issues such as pathogen reduction.

A member of the audience comprised largely of marine scientists, professionals and students inquired how Mook intended to respond to the possibility of public concerns that oysters raised with the help of a laboratory are no longer “natural.”

White assured the audience the oysters are in no way genetically modified, while later adding, “No matter what we do or say there will always be some who eschew our use of technology in favor of more ‘traditional’ methods of oyster farming or even wild oysters.”

She said scientific research in aquaculture is intended as a response to the growing possibility of food shortages caused by climate change.

“The environmental changes we have experienced and which will inexorably continue make it impossible to sustain a profitable business that can provide good jobs without using new tools and methods to reduce risk and allow dependable production,” White said. “Mook Sea Farm oysters — and all cultured oysters in Maine and elsewhere — are an entirely natural product.”

White explained that when seed oysters leave the Mook hatchery, their life cycle continues in a “natural ocean environment” in which they feed on phytoplankton.

“Shellfish aquaculture requires no antibiotics, pesticides, fertilizers, or external food sources, and extremely little to no freshwater use,” she said. “This is food production in its most natural form.”