The Sanibel Captiva Conservation Foundation has constructed a three-acre oyster reef at the mouth of the Caloosahatchee River using ancient shells. This project aims to improve water quality and support marine life in the area where the river meets San Carlos Bay. In just six months, the reef has already attracted various species.
The oyster reef, located about a mile off the coast of Shell Point, was built by marine scientists from the Sanibel Captiva Conservation Foundation (SCCF). The initiative addresses the destruction of 90% of local oyster reefs, many of which were removed and used for roadways. Doctor Eric Milbrandt, with the SCCF, explained the project's early success: "It's working right, exactly, because they are foraging. They are finding small crabs."
The shells for the reef came from a former orange grove on the Lee-Charlotte county line, provided by Bermont Materials. Joe Rice from the company described the site: "See that ledge right there. That's where your shell starts. So that layer down here, that is probably 12-13 feet of shell to get to this level. This is where those shells were that you saw in the restoration."
Within six months, the reef has become a habitat for birds, fish, and crabs. Milbrandt noted the ecosystem's activity: "So right now the birds are using it. They are finding nooks and crannies but as you can imagine, as the tide comes back in, all the fish that are in the surrounding area or maybe finding small pools to hide under the smaller fish, the crabs that all come out and start foraging on the surface and then eventually the larger fish will come and so it's kind of like a smorgasbord for juvenile redfish. They come in, they've been able to go downstream of and just sit and heat whatever is coming off the reef."
Oysters are key to water filtration, with each capable of processing 50 gallons per day. Currently, there are about 200 oysters per square meter on the reef, expected to reach 1,000 in two years. Milbrandt highlighted the benefits: "So the amazing thing about oysters is that they filter 50 gallons of water per oyster per day and right now you probably have 200 oysters per square meter, about half your dinner table but in two years, we'll have a thousand oysters per square meter and that has a tremendous benefit in terms of clearing the water and helping to remove nutrients from the water."
The water over the reef appears clear due to ongoing filtration, as Milbrandt observed: "You can see today even, over the reef where there is water, how clear the water is, and that's because the filtration process is already occurring." However, he emphasized the limited scope: "In terms of the whole bay, it's only going to have a very small impact on the area around the reef, which is why we need to build more reefs."
Milbrandt added context on the broader challenge: "We've lost 90% of our oyster reefs, and a lot of those reefs were just put on barges and used for roadways. It's like if we can replace them, we have a lot of work to do obviously, but this is one step towards that."
