Florida’s snowbirds may have packed up and headed north, but another invasion is now heading to our beaches. Each year starting in early May, sea turtles lumber ashore in the dark of night to lay their eggs in a ritual powered by millions of years of primordial instinct. It is a magical experience that most humans rarely view, and those who are lucky enough to encounter will never forget.
Marine biologists and sea turtle conservationists around the state are gearing up for another season of sea turtle nest monitoring and data gathering. Last year was a good nesting season, say sea turtle experts, continuing an upward trend over the past several years.
According to survey data from the Florida Fish and Wildlife Conservation Commission’s (FWC) Fish and Wildlife Research Institute:
- Along Pinellas County beaches, loggerheads, the most common nesters in this region, went from a low of 159 nests in 2011 to a high of 420 in 2015.
- Manatee County reported a low of 280 nests in 2011 and a high of 691 last year.
- Sarasota County reached a high of 5,274 nests in 2015, compared to 2,941 in 2011.
“It was a good year, although some significant storms caused a lot of higher than normal tides and a lot of nests washed out,” said Lindsey Flynn, associate sea turtle biologist at Clearwater Marine Aquarium (CMA). Some 75 nests were reportedly affected by severe storm events in Pinellas County during late July and early August 2015. Five nests were moved due to shoreline erosion causing eggs within the nests to wash out to sea. Three of the five nests hatched (moved eggs do not normally hatch).
Flynn works with nearly 100 volunteers and interns who monitor 26 miles of beaches from north Clearwater to St. Pete Beach. The aquarium has been involved in sea turtle nest monitoring since 1990; last year, CMA reported 216 nests compared to 201 nests in 2014. CMA reports nesting data to FWC including false crawls, disorientation, obstruction, predation and vandalism.
Five species of sea turtles nest on Florida beaches – loggerheads, leatherbacks and greens are the most common, with an occasional Kemp’s ridley and hawksbill. An estimated 60,000 to 80,000 loggerheads nest across the state each year, with four counties on the East Coast from Brevard to Palm Beach having the highest density in the world (along with Oman in the Arabian Peninsula). On the Gulf Coast, Sarasota County claims bragging rights for the highest number of nests.
Since 1989, data shows Florida’s loggerhead sea turtle nesting fluctuates in cycles of increase and decrease, ranging from a low of 28,047 nests in 2007 to a high of 59,918 nests in 1998. Last year, 52,647 nests were reported statewide.
“Loggerheads seem to be doing OK,” says Allen Foley, a wildlife biologist with FWRI who conducts sea turtle research. “Keep in mind that females won’t nest every year, sometimes it can be two, three or four years in between, and many other factors go into nesting, so one can’t assume that nesting numbers correlate to sea turtle mortality.”
Major factors that affect nesting include beach erosion and beach renourishment, severe storm events and coastal development. Whether sea turtles can adapt to these threats is something that scientists are studying, yet can’t fully predict, says Foley.
“Over time, we are dealing with a tremendous change in sea level and eroding beaches,” he explains. “In Florida’s past, the beach would naturally go in and out up to 100 feet and the turtles would adapt and survive. Now, sea level rise is happening so fast and there is so much coastal development, that turtles are coming ashore and running directly into buildings. Everything is happening more quickly now than ever before, and when things happen quickly animals have problems adapting.”
Beach renourishment projects are of special concern. The FWC Imperiled Species Management Section works to ensure protection of sea turtles by reviewing construction permits to minimize impacts to sea turtles. In general, FWC will try to avoid permitting such projects in a high-nesting area during summer nesting season, says Foley. Any nest laid on a beach in the process of renourishment would need to be moved.
Following completion, the new beaches must be monitored carefully for several years.
“The new beach is not quite ready for nesting,” Foley explains. “The sand tends to be hard and compact and there are a lot more false crawls, where they crawl up but won’t nest, and if they do, the hatchlings will often have a hard time emerging. It will actually take two or three years for the beach to get back to a more natural state.”
Sea turtle adaptation
It’s nothing short of a miracle that sea turtles continue to survive and thrive. An average of 100 to 120 eggs are dropped in a nest, yet only an estimated one out of 1,000 hatchlings reaches adulthood. First they must make it to the water by avoiding predators, obstacles and the attraction of artificial light from beachfront buildings. This lighting on nesting beaches causes hatchlings to crawl inland rather than toward the water.
“Baby turtles are programmed to go to the light as soon as they emerge,” says Kristen Mazzarella, senior biologist in charge of Mote Marine Laboratory’s Sea Turtle Conservation and Research Program in Sarasota. “That’s why it’s crucial to keep lights away from the beach. The babies can end up in swimming pools, parking lots, you name it.”
Many coastal communities have ordinances prohibiting white lights on or near the beach, which is helping, says Mazzarella. “Buildings are installing shielded lights or red or amber LEDs, but now the problem is skyglow from inland lighting. If there is any glow from inland, the baby turtles will head toward it. That’s a tougher light to manage.”
Once they make it to the water, the tiny turtles swim through the surf using magnetic orientation where they are programmed to swim six days to the loop current which takes them around the tip of Florida into the Atlantic Ocean and the sargassum line, a massive floating line of macroalgae, where they can rest and find food.
During the next 25 to 30 years, they will travel widely. Many drown in shrimp trawls; others get hooked or entangled by open-ocean longlines set to catch reef fish, sharks, tuna and swordfish. When the females are around 30 years old, they will return to the same beach where they hatched to lay their eggs. Human activities pose the most threat to sea turtle survival through loss of habitat (coastal development), collisions with boats, and discarded fishing line and plastics.
Summer storms can be devastating, so nest monitors need to keep abreast of the weather. “Tropical storms Debbie and Isaac were just two weeks apart and we lost half our nests,” recalled Mazzarella. “Fortunately, it was mid-season, so we still had half a season to continue. We always do inventories before a storm to determine which nests may be flooded or washed away. We try not to move a nest, but occasionally we will.”
Mote has been gathering data on sea turtle nesting for more than three decades with the help of an extensive volunteer program. Mote staff records tagged turtles and places tags on nesting females which help to identify returning turtles. “We have identified some turtles coming back in 10 different years,” says Mazzarella.
Last year was a record year for all species in the 35 miles Mote patrols from Longboat Key to Venice. Long-term data shows that nesting by loggerhead turtles had declined, then rebounded in recent years, said Mazzarella, while green turtle nesting— although very low in numbers—had increased.
“Green turtles are going up around the state, loggerheads have been up really high for the past four years,” she said.
Sea turtle protectors
Many sea turtle enthusiasts seem to possess a passion and devotion akin to fire and brimstone. Patrolers happily walk the beach for hours starting at the crack of dawn or sit through the night nest-watching. Volunteers set up booths and spread turtle awareness at festivals, street fairs, schools and summer camps.
Early each nesting season, volunteers visit beach resorts, hotels and condo properties dispensing educational materials. It seems to be working. Along St Pete Beach, the Dolphin Beach Resort, the TradeWinds Island Grand and Guy Harvey Outpost have switched to all turtle-safe exterior lighting.
At the Guy Harvey Outpost, Joe Widlansky of Sea Turtle Trackers, Inc., conducts Turtle Talks every Tuesday year-round on the beach. The show-and-tell educates visitors about loggerhead nesting and life cycle with the aid of a mock sea turtle nest.
Widlansky worries that despite the uptick in nesting, a downturn may be around the corner. Survival of loggerheads depends largely on humans, he opines, so the job of educating the public should never slow down.
“A lot of people have no clue that sea turtles are nesting along the beaches here,” says Widlansky, who works with a crew of 140 volunteers monitoring St. Pete Beach and Shell Key. “It’s all about education. Our job is making sure the babies get to the water and get a chance to grow up.”