Final town approvals in hand, the Nature Conservancy and several town and private agencies are all but ready to start a project they say is much-needed — re-introducing oysters to the East Branch, where they’ve all but disappeared.

The importance of oysters in systems such as the Westport River is hard to over-estimate, project proponents said — they clean the water, provide purchase for young oysters on otherwise barren bottoms and thus help the population expand, help prevent erosion and provide economic benefits to the folks who dig them, and the town as well.

Shellfish warden Rick Smith said one of the first things he and harbormaster Bill Chace decided when they were hired last year is that re-establishing the town’s historic oyster beds should be a priority — “we’ve committed a lot of time and energy to making our river cleaner and more productive,” Smith said. “This is part of that.”

The mollusks are not doing well here nor on the state level, project principals said.

“We’ve seen a 95 percent decline in wild oyster populations statewide,” added the Nature Conservancy’s Dan Goulart, who is partnering with the division of marine services on the project. “Oysters require shell to regenerate and that shell no longer exists in many of our estuaries.”

The partners’ plan is to spread shells along 10 total acres of East Branch river bottom near and around Cadmans Neck — four sites just west of Cadmans Neck, one in Cadmans Cove and two just south of the neck.

The shells are necessary for oysters to find purchase on otherwise muddy, featureless bottom, and once they are in proponents will follow up by spreading locally purchased oysters and spat. With any luck, Smith said, they’ll take.

Monitoring the project will be the Nature Conservancy, the Massachusetts division of Fish and Wildlife, the Westport River Watershed Alliance and the town’s department of marine services.

The project has been in the planning stages for months but most of the work to date has been selling it and getting necessary approvals — the conservation commission recently approved a notice of intent.

“Where there were concerns I feel like we went out and met peopl where they are,” Goulart said, noting that five public meetings were held at the Acoaxet Club, library, WRWA offices and other locations. “I think there’s been really strong public support (and) I think it will bring significant ecological benefit to the town of Westport including enhanced fisheries habitat, water filtration, improved water quality” and reduced erosion.

Members of the select board signed off on the project several weeks ago, leaving it in town administrator Chris Vitale’s hands to sign necessary approvals and work with state agencies on any further permits or approvals needed.