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Time will tell storms’ impact on island turtles

By Staff | Sep 7, 2012

Sea turtle hatchling entering the Gulf.

Despite brushes with two storms already this hurricane season, the sea turtles who nest on Sanibel and Captiva beaches will survive.

“Damage from Tropical Storm Debby was worse than the damage from Tropical Storm Isaac,” said Amanda Bryant, biologist and sea turtle coordinator for Sanibel Captiva Conservation Foundation. “When Debby impacted the islands we had more nests on the beach than for Isaac and higher than normal tides lasted longer with Debby.”

According to Bryant, 19 nests either washed away or the staking was lost on Sanibel and two nests on Captiva.

“It can be difficult to determine if the entire nest washed away or just the stakes at times,” said Bryant. “So, we monitor the area where the nest was located for signs of hatching. We never dig into the area where the nest was. This would disrupt the incubation of any eggs that may be still in the nest.”

SCCF has replaced the lost staking at all nest sites.

The really good news, though, is that when Isaac impacted Southwest Florida, nesting season already had finished on the islands.

“Storm events are a natural part of a sea turtle’s life and nesting,” said Bryant. “They’ve encountered storm events for as long as they have nested on beaches. Events like this have little impact on the overall survival of the species. Females come ashore to nest roughly every other year and lay several nests (up to six) over the course of one nesting season as adaptation to nesting during hurricane season.

“Sea turtles are also very ling lived. Combined, these factors mean one nesting season with reduced hatching success has little effect on the overall population. It’s also important to remember that Sanibel and Captiva and even the larger Southwest Florida area are but a small area of nesting beaches for sea turtles. So, while our nests were impacted by these storms, many nesting beaches throughout the Southeastern U.S. saw no impact.”

SCCF’s own sea turtle activity as of Aug. 31, which is closely monitored, bear that out. Over the past three years, the number of nests on Sanibel and Captiva at this time of year has increased each year. The number of false crawls observed also has grown, more than doubling in some cases, while hatches are down slightly over last year and about the same as two years ago.

“There have not been any nests since the storm,” added Bryant. “We have not had a loggerhead nest laid since early in August.”

We may never know the full extent of turtle loss due to these storm incidents.

“Part of the reason we have to wait and see what the impacts are to individual nests is because the length of time a nest was under water as well as where the nest was in embryo development play a role in how well a nest handles being inundated with water,” said Bryant. “Typically, nests that are briefly washed over or are early in development handle being washed over better than nests that are under water for a long time or close to hatching. Since we have no way of knowing what goes on under the sand’s surface in a nest, it is difficult to predict how badly a nest will be impacted by a storm.”

It means just watch, and wait to see if a nest hatches.

There is nothing anyone can do to encourage nesting other than the conservation practices already in place – maintaining a turtle-friendly beach year-round with no beachfront lighting, holes or other obstacles to nesting turtles, and for beachgoers to maintain a safe distance from staked nest areas.