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Saving the Bay, One Bivalve at a Time

Aug 02, 2012 05:33PM ● By Anonymous


Environmental scientists at the University of Maryland Center for Environmental Science Horn Point Laboratory Oyster Hatchery have pushed out more than one billion spat into the waters of the Chesapeake Bay over the past ten years. In 2011 alone, they produced roughly 600 million. And on a blessedly non-sweltering Tuesday, visitors on the Pearls of Wisdom tour got to see how it was done.

Throughout the winter, adult oysters are kept on over-wintering floats in the Choptank River. Come January, Horn Point employees move them into the broodstock conditioning lab, where they’re slowly warmed up until the water around them (still brought in from the Choptank) reaches a temperature of 74°F. As they chow down on phytoplanken, the oysters put all of their energy into developing eggs and sperm, or gonad.

After about two months, they’re cooled down and allowed to spawn throughout the summer. Lucky groups of oysters are selected from the conditioning system, placed on spawning tables, and warmed back up. If they aren’t inspired to spawn, gonad is introduced and, by all accounts, they go nuts. Let the spawning frenzy commence.

Once the oysters are done spawning, their eggs are transferred to large growout tanks, where they mature for 2 – 3 weeks. (Don’t you wish humans matured this quickly?) While they’re in the tanks, the larvae are fed a diet of algae, which is grown in an adjacent greenhouse and delivered to the larval tanks via the hatchery’s computer-operated feeding system.


Alas, all larvae must grow up some time. Usually, those near the 14-day mark develop and eye-spot and a foot, and, if they’re big enough, are ready to set. Outside in the large outdoor oyster tanks, the larvae are allowed to get comfy cozy on top of shell.

It’s at this point that the Oyster Recovery Partnership takes over.

Founded in 1994, ORP brings together scientists, state and federal government agencies, conservation organizations, and watermen together to restore oysters in the Bay. Their efforts have resulted in the re-establishment of more than 70 oyster reefs from the Magothy and Severn Rivers all the way down to Tangier Sound. And, they’ve even begun selling oyster larvae, seed, and shell.

If you’re wondering where the shell for the Horn Point larvae comes from, ORP is responsible for that too. Through their Shell Recycling Alliance, environmentally-responsible restaurants, caterers, and seafood distributers can donate discarded shells exclusively to the hatchery.


Owings Mills’ The Classic Catering People have been a part of the program for two years.

“We do a lot of bull and oyster roasts in the summer,” says chef Bryan Davis. “When we do, we make a point of telling guests what we’re doing with the shells and asking them to bring them back and put them in the recycling bins. Once they realize what we’re doing, they really like it.”

ORP goes and picks up the shells twice a week, and takes them back to Horn Point, where they’re allowed to sit for a year and are then cleaned by ORP employees.

“The cleaner the shell, the better the set,” says ORP’s executive director, Stephan Abel. “The better the set, the more oysters we get out.”

If everything goes according to plan, each recycled shell will result in ten bitty oysters’ being replaced to the Bay.

About 48 hours after the folks from Horn Point deliver the larvae to the outdoor oyster tanks, ORP examines them under a dissecting scope to see if they’ve successfully attached. If they have, they can now be officially deemed spat and are introduced to ambient river water (again containing the tasty naturally-occurring phytoplankton).  Soon, they’ll have eaten and grown their way out of the setting tank and into the nursery in a shallow part of the Choptank River. Sometimes, they’re big enough to go directly onto a prepared site.


Once they’ve reached a predetermined size (be it in the outdoor oyster tanks or the nursery), the spat and their shell are dumped directly onto ORP’s planting vessel, the Robert Lee, and are then taken to a designated planting site and pitched overboard.

Don’t worry if this sounds harsh to you—an oyster can handle it. Even a baby one.
“It doesn’t know if it’s upside down; that’s a human thing,” says Horn Point’s Dr. Mutt Meritt, hatchery program director and trusty leader of the Pearls of Wisdom tour. “It can stand on its head!”

Throughout the year, scientists from the the University of Maryland Paynter Labs and Morgan State keep a close eye on how the newly-planted oysters are doing.  


So far, ORP’s plantings have been a success. They’ve gone from 2 million in 1998 to 458 million 2010. Their goal is 2 billion.

If you’d like to help them reach that goal, there are tons of ways to help out. You can donate, volunteer, or just read a little more.

If you’re interested in visiting the Horn Point Hatchery, stop by on October 13th. They’re having an open house.