SCCF wraps up record-breaking sea turtle season
With the second-highest number of nests on record for both loggerhead and green sea turtles and a new record number of hatchlings, the Sanibel-Captiva Conservation Foundation recently finished tallying up an amazing comeback season on the islands.
“We were just 24 nests short of our record for loggerheads on Sanibel and only one nest away from our record for loggerhead nests on Captiva,” Sea Turtle Program Coordinator Kelly Sloan said.
Aside from regular monitoring of sea turtle nesting season, which runs from May to October, SCCF staff also took on a number of research projects intended to increase understanding of sea turtles.
“Our dedicated team put in a lot of work across all aspects of our program, from nest monitoring to stranding response to research projects, contributing much to the successes we’ve seen this year,” Sloan said “We also are so appreciative of our volunteers. With their hard work and positivity, they keep the sea turtle program running.”
Nearly 100 volunteers logged 5,426 hours this season, the highest amount ever, showcasing their passion for conservation during an extremely busy season. A total of 850 nests of loggerhead and green sea turtles produced a record number of 48,444 hatchlings on both islands.
Staff conducted five research projects during the course of the season, including: a sea turtle tagging project; two brevetoxin accumulation studies to investigate the impacts of red tide on sea turtle strandings and in nesting females; a green sea turtle satellite telemetry project; and a groundwater impact study.
The sea turtle tagging project started in 2016. Since then, 636 unique turtles have been tagged, measured and identified on Sanibel. The average size of a loggerhead 94.5 centimeters long and 66 centimeters wide. The night-time tagging project achieved a new record with 352 turtle encounters.
“Staff interacted with 1,126 beach-goers, handing out red light filters for flashlights and educating them on sea turtle friendly beach practices,” Sloan said.
In their red tide research, the team is working with scientists from SCCF’s Marine Lab to collect and test tissue samples to determine brevetoxin concentrations in sea turtle strandings. They are also examining sea turtle stomach contents to see how what they ingested may have impacted the level of brevetoxins. Preliminary results show red tide as a likely mortality factor in nearly all of the turtles sampled.
“We’re also evaluating the impacts of red tide on maternal health and potential transfer of brevetoxins to hatchlings,” Sloan said.
The green sea turtle satellite telemetry study, conducted in partnership with the Conservancy of Southwest Florida since 2017, has placed a total of 10 satellite tags on turtles on Sanibel and four on Keewaydin. During the 2019 season, SCCF researchers tagged four green sea turtles.
“The objective is to determine the post-nesting and inter-nesting movements of green turtles nesting in Southwest Florida,” she said.
To further research in hatchling sex ratios as well as hatching and emerging success, the team quantified the impact of groundwater on nest temperature, salinity and moisture content. Groundwater wells and microstations with sensors were deployed at 20 loggerhead nests in 2019 and nearly 600 hatchlings were sampled for sex determination.
To report any issues with sea turtles, call the SCCF hotline 978-728-3663.
To find out more about SCCF’s program, visit www.sccf.org/our-work/sea-turtles.