Thousands of baby oysters have been moved into their new home for the next nine months: a solar-powered barge that will make it easier to grow the bivalves in deeper waters, opening the door for more effective oyster restoration and aquaculture in the Chesapeake Bay and beyond.
The prototype barge is the product of Solar Oysters, LLC, a partnership between the Maritime Applied Physics Corporation (MAPS) and the EcoLogix Group, Inc.
“This is a really exciting day for us,” said Steve Pattison, a principal at EcoLogix and the business manager of Solar Oysters.
Pattison hopes the barge will be a boon for the health of the Chesapeake Bay, oyster farmers’ businesses, diners’ palettes, and waterfront property owners’ views.
Staff from the Chesapeake Bay Foundation and Solar Oysters loaded about 300,000 shells covered with baby oysters, or spat, into cages and onto the barge last week.
After growing on the barge for nine months, the oysters will then be transferred to a sanctuary at Fort Carroll, in the Patapsco River south of the Francis Scott Key Bridge, where they will help repopulate the Bay and filter its waters.
The Abell Foundation awarded a grant of $150,000 over two years, which will fund the barge as well as the Chesapeake Bay Foundation’s oyster gardening and STEM education initiatives.
Oysters grown in the Baltimore Harbor are not safe for consumption, so the 40-foot-long, 25-foot-wide barge is currently growing oysters for restoration efforts.
But Solar Oysters plans to develop more barges, some as large as 160 feet by 54 feet, which they will sell or lease to aquaculture farms in other parts of the Chesapeake Bay or elsewhere to grow oysters for eating.
The prototype barge has a 12 solar panels, which together can generate about 24 kilowatt hours of energy per day, said MAPS President Mark Rice. The larger barges will be equipped with more solar panels, proportional to the size and energy needs of the barge.
Rice said Solar Oysters has not yet determined how much each barge will cost to sell or lease, but that they will have to be able to grow an oyster for about 24 cents.
The barge uses a rotating mechanism that Chesapeake Bay Foundation senior scientist Doug Myers likened to the Zipper ride at a carnival, albeit much slower.
The mechanism rotates the oysters up and down the water column, exposing them to different water depths, salinity levels and food resources. When the cages surface once a day, the sunlight helps kill off bacteria, Myers said.
Over the years, the oysters of the Chesapeake Bay have been ravaged by disease, as well as over-harvesting, Myers said. Currently, the bay’s oyster population is about 2% of its historic levels.
An adult oyster can filter 50 gallons of water per day, and historically the Chesapeake Bay was home to enough oysters to filter all of the Bay’s water in about three days. Now, it can take up to a year for the Bay’s current oyster population to filter that much water, Adam Lindquist, director of the Healthy Harbor Initiative at the Waterfront Partnership of Baltimore, told Baltimore Fishbowl in September.
Restoring the oyster population is integral to improving the health of the Baltimore Harbor and the broader Chesapeake Bay, Myers said.
“A mature oyster reef in salty water can support up to 300 different species,” he said. “We don’t think we’ll have quite that many here in the harbor, but dozens at least, and all of those are helping to filter the water.”
A report from the Waterfront Partnership of Baltimore in September 2021 found that bacteria levels in the Baltimore Harbor are improving and that dissolved oxygen levels have been “consistently good to moderately good.” But the report’s authors noted that there is still much work to be done to improve other health indicators, including conductivity levels and investment in stormwater management.
Another report, from the University of Maryland Center for Environmental Science in June 2021, found that the Chesapeake Bay’s overall health has improved slightly. But the Patapsco and Back rivers, which feed into the Baltimore Harbor and other parts of the city, received lower scores across most health indicators than other regions of the Bay, including a “very poor” score for its benthic community, which includes oysters and other bottom-dwelling organisms.
The Chesapeake Oyster Alliance — a coalition of nonprofits, community organizations and oyster growers across Maryland and Virginia, including Solar Oysters and the Chesapeake Bay Foundation — has committed to adding 10 billion oysters to the Chesapeake Bay by 2025.
As of the end of September, the coalition had grown 2.67 billion oysters since 2017, Myers told Baltimore Fishbowl in September.
The barge is self-sustainable, with solar energy powering all of its operations, including rotation of the oyster cages, an anti-poaching surveillance system, navigation lighting, ship-to-shore communication, cellular connection, water quality monitoring equipment, an oxygenation system, and an automated system for spray-washing biofoul off of the cages.
Biofoul, or the accumulation of bacteria and other organisms, can obstruct food and oxygen from reaching oysters, so keeping their cages clean is important, Myers said.
Instead of workers manually scrubbing biofoul off of oysters cages, the barge’s automated system will spray-wash them, Pattison said.
“Workers have to go out in a skiff, typically bend over or get in the water, and do that by hand in the water,” he said. “So it’s a much better environment and a work condition for laborers and workers.”
The rotation of the oyster cages also creates a tumbling motion, which helps creates a thicker shell with a deeper cup, Pattison said.
“That’s what a lot of consumers who go to an oyster bar, when they buy an oyster on the half shell, they like to see an oyster with a deep cup on it,” he said.
And each time an oyster breaches the water’s surface, they shut their shell tightly. Over time, that opening and closing of the shell makes the oyster stronger and healthier, Pattison said.
Another benefit of the barge is its ability to grow more oysters in a smaller area.
Traditional floating oyster farms use cages suspended on a line across several acres of water. But with the solar-powered barge, “we can grow orders of magnitude more oysters on a much smaller footprint,” Pattison said.
Other types of oyster farms anchor cages to the bottom of the floor of the water body, which can result in increased instances of disease, Rice said.
“One of the issues when you bottom farm oysters is you’re closer to all the bacteria and organisms that are in the mud,” he said. “If you keep the oysters up in the water column, potentially they stay healthier.”
Baltimore’s harbor is “one of the hardest places to grow oysters,” Myers said, which makes it the perfect place to test out the barge.
“If you can do it here, you can take this technology out to better water that’s cleaner and has more dissolved oxygen than here and certainly raise a lot of oysters,” he said.
Solar Oysters also hopes their barge will be well-received by waterfront property owners because the barge can be parked far away from the shoreline. The oyster cages are rotated vertically along the water column, so the barge needs water depths of at least 20 feet.
Once aquaculturalists are able to begin using the solar-powered barges in deeper areas of the Chesapeake Bay, the oyster farms will be virtually unnoticeable by waterfront property owners, Myers said.
“One of the big things holding back aquaculture in the Bay is it’s usually done really close to the shoreline, and so waterfront property owners object to it because it looks ‘weird’ or ‘aesthetically displeasing’ to them,” Myers said. “This platform can float way offshore where they can’t even see it or it’d be very minimal visual disturbance, and it can grow millions of oysters.”
Alongside oyster restoration efforts, the barge makes Myers optimistic about the future of the Baltimore Harbor.
“For so many years, it was just this dirty, toxic place, and now there’s hope,” he said.