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Oyster restoration important in aiding water quality

By Staff | Nov 25, 2015

SCCF volunteer Troy Gembecki, dumps a bucket of fossilized shells out into Tarpon Bay on Veteran’s Day. BRIAN WIERIMA

Oysters play a much more important role than just being served steamed or raw on some restaurant table, ready to be consumed by a a visitor on vacation.

The importance of oysters in the environment is largely overlooked, but what they provide in water quality, is vital.

That’s why the Sanibel Captiva Conservation Foundation is aiming to rebuild the depleted oysters reefs off the shores of Sanibel, an oyster restoration project which now has three sites being built on.

“We are working on three places to rebuild the oyster reefs, and they are located in Tarpon Bay, San Carlos Bay and the third at the southern part of Matlachay Pass,” said SCCF Marine Laboratory Director Eric Milbrandt. “Oysters basically grow on anything which is hard, and that includes such things as rip-rap and shells.”

The oyster restoration project directed by the SCCF looks to improve the oyster reefs, which were nearly destroyed completely in the Sanibel area.

Oysters most important ecological function is to filter the water. They remove organic and inorganic particles from water and also can remove microscopic phytoplankton. In essence, oysters help remove harmful algae biomass from water.

Oyster reefs, or areas were numerous oysters live and congregate, also provide habitat for marine wildlife. Regrowing the oyster reefs is a vital part of nurturing water quality.

“In this area, 90 to 95 percent of the oyster population was destroyed by either poor water quality or by road construction,” Milbrandt said. “They can filter up to 20 to 25 gallons of water per day and they also help stabilize the bottom of the bays.”

The SCCF received a large delivery of fossilized shells, which is piled up near the Sanibel Dock park. For the last several months, SCCF volunteers and staff have been loading up the shells in five-gallon buckets and transferring them to a barge located near one of the three sites.

“Each bucket contains about 30 to 35 pounds of shells and barge loads hold about 100 to 130 buckets,” Milbrandt said. “So far in one week, we move 20 cubic yards of shells. We average 10 barge loads per week and anywhere from three to four trips per day when we get enough volunteers.”

The goal at each of the three sites is to cover six inches to a foot of the fill and work will be done up to the end of the year, even into 2016 if need be.

Milbrandt had to go through a long and strenuous permit process to gain access to the sites, which included working on reefs with a low amount of sawtooth fish, which are endangered in the area.

Each area also have relic reefs, or reefs which are currently dead.

The SCCF successfully rebuilt oyster reefs in the Clam Bayou area on Sanibel in 2009-10 and after the second year after the work was done, there were self-populating oyster populations.

“We don’t really know the size and the extent of the oyster reefs in the area, because they have never been mapped out,” Milbrandt said. “Our current projects only cover two acres, compared to the thousands of acres which is in the Pine Island Sound.”

A healthy oyster reef will have around 1,000 to 1,500 oyster per square meter, but in a nearly dead reef, only 50 oysters are found per square meter.

“The peek settlement period is September through November,” Milbrandt said. “When the weather cools down, the spawning slows down. Within six months, we should have oysters colonizing at the three sites, but it will take two to three years to have it looking like an oyster reef.”

The typical work day for an oyster restoration volunteer includes filling the buckets up at the Sanibel Dock site, loading them onto a trailer and transferring them to one of the three sites, where the buckets will be loaded onto the barge.

Then a boat will haul the barge out to the site, where the buckets are dumped in a specific area, with water usually only being knee deep.

“The more volunteers we have, the more we are able to get done,” Milbrandt added.

To volunteer for the SCCF oyster restoration project, go to www.sccf.org or call 239-472-2329. Email is also acceptable and do so at sccf@sccf.org.