Stay in the know about wildlife, water quality, and ecosystems on Sanibel and Captiva Islands and in Southwest Florida

How Hurricanes Impact Sea Turtles

September 13, 2023
sea turtle on sanibel
sea turtle nest that had been buried under sand
Nest that had been buried in sand

Following Hurricane Idalia on Aug. 30, SCCF sea turtle staff and volunteers have been working tirelessly to respond to impacts to sea turtle nests.

This includes confirming the presence or absence of nests that may have had their marking materials washed away, or nests that were buried under — in some instances — several feet of sand. After digging out nests, SCCF creates a ‘ramp’ for hatchlings.

While the process is ongoing and at least 62 nests were completely lost, 27 were found and remain on the beach. One nest even hatched the day after the storm!

How do sea turtle nests on the beaches fare during storms?

Nests that are incubating on the beach as a hurricane arrives do not have the ability to move and occupy a space more sheltered from a storm’s path.

“It’s important to note that it is not feasible for humans to remove the eggs from the beach to incubate elsewhere in anticipation of a storm’s arrival,” said SCCF Sea Turtle Biologist Jack Brzoza said. This would likely have a detrimental effect on the embryonic development and hatch success and is not a tactic that is permitted here in Florida.”

Storms often affect incubating nests through tidal inundation and through changes to nesting habitat resulting from erosion or accretion.

Sea turtle eggs are permeable, allowing for gas, water, and heat exchange, which is necessary for successful incubation and embryonic development. Prolonged submersion from tidal inundation or significant storm surge can cause embryonic mortality — if submerged too long, the eggs essentially drown.

“However, the arrival of a hurricane or major storm do not mean the loss of all nests on the beach due to drowning. In some instances, nests may be washed over by the tide, but only briefly,” Brzoza said. “Nests can survive a wash-over event, or even several wash-overs. In some instances, it may be beneficial by having a cooling effect on the nest.”

Sand Erosion and Accretion

Erosion can result in total nest washouts when sections of beach are lost to tides and storm surge. Less severe erosion may reduce the distance from the eggs to the sand surface. This can alter temperature of the egg chamber, which has the potential to affect hatch success.

uncovering sea turtle nest after storm on sanibel
Unburying a heavily accreted nest on Sanibel after Hurricane Idalia

Storms can also deposit additional sand onto the beach and incubating nests, known as sand accretion. Additional sand on top of a nest can also create temperature differences and make it more difficult and energy-demanding for hatchlings to reach the surface of the sand.

How are sea turtle adults out in the ocean affected when a storm arrives?

During extreme weather events, some sea turtles alter their behavior. Studies have shown — usually through data collected via satellite transmitters — that adult sea turtles will change their diving patterns, often diving deeper and for longer periods while a storm passes.

Other turtles have been observed moving into areas closer to the storm’s periphery, where changes in wind speed, pressure, and/or temperature may be less severe. These movements to calmer or deeper waters are typically not the result of long journeys but rather a shift in use of habitat they currently occupy within the path of the storm.

Data obtained from the transmitters before, during, and after a storm has passed confirm the turtles’ survival. However, in some instances, turtles’ transmitters stopped sending a signal post-storm. While uncertain, this could be explained by the turtles not surviving or the transmitters failing or falling off.

“In essence, through such behavior, many turtles have been observed to ‘ride out’ storms, which shows their adaptability and resiliency to these natural occurrences,” Brzoza said.


Archives by Month