Oysters are not like clams.

On an afternoon in early July, that was a key fact when David Colvin, Jr., explained why he and a few other members of Old Saybrook’s Shellfish Commission (SC), along with the co-owners of Indian River Shellfish, an oyster farming business that operates on Long Island Sound in Clinton and Madison, were depositing shells into the Oyster River.

“Clams can move up and down in the mud, in the sand, so they don’t get covered up,” Colvin said. “The oyster has to stick to something that’s hard. They stick to rocks, concrete, other oyster shells.”

At this time of year, oysters reproduce and “release these microscopic little seed into the river,” he continued. The larvae “float around and they settle—if they settle into mud, they just die. If they settle onto something and they can stick to it, they grow.”

Larvae that have settled onto a surface are called spat.

“So what we’re doing is we’re putting shell down, fresh shell on the top of the surface,” said Colvin. “In the next couple of weeks, when they reproduce, we’re hoping that they stick and we get a set. We’re trying to get oysters to set.”

It’s been a while since the Oyster River was filled with oysters. Colvin guesses there might be a 100,000 oysters in the river.

“But 100,000 oysters is just a drop in the bucket,” he said. “There are supposed to be millions.”

In previous centuries, Old Saybrook had a robust oyster industry, but from the mid-20th century on, oyster populations dropped. The town unsuccessfully tried to get back in the game in the mid-’90s by getting state permission to re-open the beds, but the Oyster River regularly silts over, and mud is clearly visible on its banks.

Now the town is again working with the state to test the water on a regular basis, said Old Saybrook Director of Public Works Larry Bonin, who is also an SC member. It’s a two- to three-year process of collecting data “to see if we can open the area to shellfishing,” he said.

Bonin operated a front loader to deposit heaps of shells from Cornfield Point beach onto a small motorboat with plywood laid across one end. SC member Andrew Pandiani and Mike Gilman of Indian River Shellfish shoveled the shells into the river while Indian River’s George Harris steered the boat.

Colvin and fellow SC member Shannon Duggan were on hand to take turns with the shoveling.

Oysters are not just a tasty and nutritious food. They are natural water filters, straining the water for algae and other nutrients. This in turn allows other plants to grow, thereby creating habitats for other underwater species. Oysters themselves are ideal surfaces for other oysters to cling to—as these structures grow, forming complex reefs, they provide hiding and hunting places for other species.

Oystering itself helps dredge the river, Colvin explained.

“As soon as the last oyster guy stopped oystering, all the oysters that were there as it silts in, this black muck, it just covers them over and kills them,” he said.

Oystermen remove the flesh of the oyster and toss the shells back into the river, giving the larvae something to latch onto.

The activity of oystering also stirs up the silt.

“The oystermen are doing everyone else a favor because they’re keeping [the river] dredged—you lift up that muck and the tide takes it out, and keeps [the river] navigable,” Colvin said.