A delegation representing diverse interests in Maine’s marine economy recently returned from Hokkaido, Japan, where the members studied sea urchin farming and wild harvesting techniques and how the techniques might be adapted to strengthen Maine’s industry.
The group learned about different forms of Japan’s sea urchin fishery, ranging from open water wild harvest to bottom leasing, confined structures and submerged cage culture, said Hugh Cowperthwaite, Brunswick-based Coastal Enterprises Inc.’s senior program director for fisheries and aquaculture. Cowperthwaite helped coordinate the trip along with Dana Morse, Maine Sea Grant and University of Maine Cooperative Extension.
The delegation spent five days visiting hatcheries, farms, processors and research facilities across Hokkaido, Japan’s northernmost main island.
The Japanese use of hatcheries to produce urchins was compelling, said Cowperthwaite. Urchins are then seeded on the sea bottom for harvest.
History of collaboration
The trip built on a history of collaboration between Maine and Japan’s marine industries, particularly in scallops. Previous Maine groups have visited Japan’s northern prefectures of Aomori and Hokkaido, both of which have a climate and seasonality like Maine and are rooted in natural resource-based economies, to study the farm-raised scallop industry.
Maine urchin woes
Maine’s fishery for the spiky sea urchin expanded rapidly in the 1980s and 1990s, when global markets embraced the state’s high-quality roe, known as uni, considered a tasty delicacy.
Since then, declining populations have limited the fishery. The fishery has stabilized in recent years, but remains overfished and stock levels are a concern, according to Maine Sea Grant.
Urchins can be raised to market size, but achieving profitability at scale is a challenge, Sea Grant said.
The delegation included representatives from the Department of Marine Resources, the University of Maine Center for Cooperative Aquaculture Research, the University of Rhode Island and private aquaculture companies. Funding for the trip was supported by the National Sea Grant Program.
Farm to harvest
Sea urchin farming could offer new and diversified opportunities for Maine fisheries, but the sector in Maine is just getting going, said Cowperthwaite.
“The idea was, ‘Let’s see what the Japanese are doing around sea urchins, that we could be doing here,’” he said.
Particularly interesting, he said, was the coordination between urchin farming and harvesting.
There are about 40 sea urchin hatcheries around Hokkaido. They produce and raise seven species of urchins and then release them into the wild in different regions around the prefecture. The urchins are then available for harvest, with the seasonality staggered through they year. Harvesters are organized into co-ops, which determine when and who can fish.
“That’s a pretty interesting model that I think could be considered here in Maine on an approved lease site,” he said.
At one hatchery, the group saw how a broodstock urchin was placed upside down on a glass where technicians pour warm seawater onto the creature’s mouth to trigger it to spawn.
“Sea urchins are broadcast spawners and release clouds of eggs and sperm from five small openings called gonopores, located on the top of their body into the water,” said Cowperthwaite. “In the hatchery, the eggs and sperm are then transferred to larger tanks.”
Esan Fishing Co-op at Yamasedomari harvests purple sea urchin and another similar to Maine’s green sea urchins. With 80 boats and 500 fishermen, the co-op raises 1.6 million urchins per year in a hatchery, releases them to the wild and harvests by stick-net.
Primed for opportunity
The technical aspects of raising urchins in hatcheries didn’t appear to be overly complicated, he said. And Maine already has production underway, including Springtide Seaweed in Gouldsboro, which is seeing success with its urchin hatchery production and marketing of products.
Steve Eddy, director of the University of Maine Center for Cooperative Aquaculture Research in Franklin, has expertise in aquaculture systems, including hatchery trials with green sea urchins in recent years. Seth White, owner of Sol Mariculture LLC in Brunswick, grows a poly-culture of oysters, urchins and seaweed, according to his biography.
“Sea urchins seem to be a species primed for opportunity,” said Cowperthwaite. “We have a number of growers and fishermen who are now confident and able to produce farmed kelp, and that’s what sea urchins eat. It seems like piecing this together could make sense and offer some new and diversified opportunities for Maine fisheries.”
The group plans to debrief and discuss next steps in July, he said.
