ANNA MARIA – Damon Moore outlined his vision for local oyster habitat restoration during a Feb. 21 presentation at The Center of Anna Maria Island.
Moore, the founder and executive director of Oyster River Ecology Inc., began with the historical abundance of oysters in local waters and their subsequent decline.
“The oldest reference I could find to the Manatee River was in 1792,” Moore said, when explorers referred to the river as the “River of Oysters.”
From 1876 to 1897, he said the waters went from “oysters, oysters, everywhere to totally depleted” due to the commercial oyster trade.
“It gets worse. A lot worse. Manatee Avenue was originally a sandy road which was paved with oyster shells which were taken from the river,” Moore said. “For several months after, the oyster meat rotted and Manatee Avenue was the most odiferous street in the whole United States.”
From 1931 to 1962 the Bradenton Dredging and Shell Company removed more than 650,000 cubic yards of shell from the Manatee River, he said.
Moore said the current decline in the oyster population is due to water quality issues including water pollution, altered freshwater flows and increased erosion and sedimentation.
“When you put a big dam on the Manatee River that changes how much fresh water comes in, I call it the Goldilocks zone of salinity,” Moore said. “When you’re an oyster, if it’s too fresh, you close up and you don’t open, you will starve to death. If it’s too salty, you’re fine with that but so are all of your predators.”
Moore said the problem locally was overharvesting of hard material that oysters need to thrive and create oyster beds.
“What restoration projects generally consist of is returning that hard material into the water column to allow them to grow,” Moore said. “We don’t have to seed them. We’re lucky there’s enough of an existing population growing in mangrove roots. There’s plenty of larval oysters.”
“When I’m talking about restoration I’m talking about restoring a population of oysters that existed in the Manatee River,” he said, adding that restoration can take place through both community-driven and contract-driven projects.
“Vertical oyster gardens are very popular,” he said. “This is something you can do on your own dock. The docks on Anna Maria Island, you’re in really high salinity waters. If on docks or seawalls, the predators can’t jump which gives the oysters an extra level of protection.”
A vertical oyster garden is typically a string of recycled shell which can be hung from a dock where oysters can grow. Once they’ve reached a certain size, they will fall off into the water and coalesce into an oyster reef, Moore said.
He compared barge and backhoe placement of 6 inches of limerock at a per acre cost of $635,000 to the $216,000-per-acre cost of 12-inch metal pin vertical oyster gardens.
“That’s a significant savings,” Moore said.
“Restoration targets are 300 acres by 2050 for Tampa Bay in the 2020 Tampa Bay Estuary Habitat Management Plan,” he said. “For 300 acres, the cost is $190,680,000 for barge and backhoe compared to $64,947,960 for 12-inch metal.”
