Predators and parasites are having a field day in the bay, thwarting the reproductive capacity of oysters to rebuild their populations on the bars where they live.
DAVID ADLERSTEIN Apalachicola Times Editor ApalachTimes
APALACHICOLA — A five-year study designed to determine the optimal densities for planting oyster shells in the Apalachicola Bay is yielding a bushel full of additional data on how the oyster reefs respond to changes in water quality.
And so far, the findings are giving scientists only a thimble full of optimism.
In a detailed presentation Tuesday night at the Apalachicola Community Center, representatives from the University of Florida and Florida Fish and Wildlife Conservation Commission, the two lead agencies conducting a five-year project funded by the National Fish and Wildlife Foundation, offered details on what they have found two years into the study.
Discovered so far is that predators and parasites are having a field day in the bay, stymieing the reproductive capacity of oysters to rebuild their populations on the bars where they live.
“These are not good times for oysters in Apalachicola Bay,” said Kane. “This is as low as it’s been since 1985.”
Kane outlined a scenario in which field samples collected since May 2016, from each of the three experimental sites at Hotel Bar and Bulkhead Bar near the St. George Island Bridge, and Dry Bar to the west of that, have shown lots of dead oysters and plenty besieged by the predatory southern oyster drill and boring sponges.
“Large egg masses were abundant. The reproductive capacity of these snails are out of control, and sponges are having a really good time,” he said. “Being an oyster on a oyster reef is a really tough life.”
Kane showed slides of shells riddled by channels carved by sponges, and those of shells completely encased in egg sacs. “This is a huge issue for reef stability over time,” he said.
The good news, what little there was, is that scientists have found a diminishing presence of the dermo disease, which can be fatal to oysters.
In addition, the amount of spat being produced by oysters in the bay is a goodly number, as demonstrated by work done by a team of divers under the direction of Melanie Parker, with FWC’s Fish and Wildlife Research Institute out of St. Petersburg.
Parker said there is “a phenomenal spat set,” but as the oysters grow over 18 months to full maturity, and their numbers decrease.
She said that will 300-400 cubic yards per acre seems to be optimal for growth, oysters do not appear to be growing to full maturity at the rate that they ought to be. “I really want to see the next quarter’s sampling,” she said. “It’s possible we didn’t hit the larger ones because there’s not a lot of them to begin with.”
Another possible explanation, according to Shannon Hartsfield, president of the Franklin County Seafood Workers Association, is that unethical harvesters are snatching them from the cordoned-off experimental sites, thus depleting the big ones.
“He said he has reported some of these instances to FWC. “But by the time they get there, they’d be off the site,” he said. “A lot of days are foggy, foggy.”
Parker said it is too soon to say, without further evidence, what effect this harvesting may be having on the researchers’ findings.
Kane said that while he does not make policy for the bay, he is inclined to support a closure that could help in replenishing the reefs.
“The substrate needs to be restored,” he said. “It needs to be stabilized. You have to shell it, you have to nurse it that way.
Retired oysterman Jerry Williams said he is inclined to support some sort of temporary closure as well. “The alternative is worse,” he said. “Over time, if you keep it closed, the odds are better it will rebound.
“I don’t want to see it destroyed,” he said. “I raised a family on it. It’s shame what the state of Florida has done (with its management). They were told it was detrimental to this bay, and they knew better.”