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

SCCF Sea Turtle Team Does More than Monitoring

May 31, 2022

SCCF’s sea turtle team has recorded over 220 total nests for the season. Aside from monitoring, the team is also gathering blood samples during night surveys that are being used in vital research projects.

Nest Monitoring

After several busy mornings of volunteers documenting 7-8 nests along the west end of Sanibel, the team has documented 134 total loggerhead (Caretta caretta) nests just for that stretch. While it may have seemed like a slow start this year, current counts are actually very similar to 2021’s nest counts on this date. 

This past week especially was a big one for Captiva, where nesting has been noticeably lagging so far this season. But after several mornings of 4-5 nests, it seems the turtles have finally shown up and Captiva’s nest counts are rebounding quickly, with a total of 52 nests now.  

Last week, the team found the first green sea turtle (Chelonia mydas) nest of the season! “The nest was discovered on a morning survey, and the turtle was not seen at night, so we are unsure if she was a returning female from a previous season or perhaps a new green turtle we have never seen before,” said Coastal Wildlife Biologist Jack Brzoza. “We’ll be on the lookout for this turtle as we hope to see her again.” 

Research on Loggerheads

For the third nesting season, the SCCF team is collecting blood from a subsample of loggerheads nesting on Sanibel. “In addition to our own research, these small blood samples are contributing to three collaborator projects and will provide important information that helps managers better protect these fragile populations that face so many threats,” said Coastal Wildlife Director Kelly Sloan. The bloodwork is informing these studies:

  • The SCCF Sea Turtle Program is looking at the long-term, sublethal effects of red tide blooms on the health and reproductive success of nesting loggerheads on our beaches. 
  • Dr. Simona Ceriani with the Florida Fish and Wildlife Research Institute will process for stable isotope analysis, a tool that allows researchers to identify the general area where each female forages and resides when she is not at the nesting beach. This is possible because isotopic values differ in nature across space, making the saying “you are what you eat and where you eat it” true. This technique is used in a variety of fields from human forensics to aid solving crimes to food traceability, i.e. the label of a wine bottle says it’s from Italy—is it really true?
  • Dr. Brian Shamblin with the University of Georgia will use the blood to create individual genetic tags to test for relatedness among nesting females and to track offsite nesting of individuals.
  • Dr. Justin Perrault, Loggerhead Marinelife Center, and Dr. Annie Page-Karjian, Florida Atlantic University, are doing a statewide disease assessment survey for ChHV5 and ChHV6. ChHV5 is associated with the disease fibropapillomatosis (known as FP) and ChHV6 infection is associated with lung-eye-trachea disease. The idea for this study came about because seven loggerheads that were sampled for a previous in-water project tested positive for both viruses. This project will provide an idea of exposure for nesting and foraging loggerheads in Florida.

SCCF is also participating in another research project led by Dr. Tomo Hirama of the Florida Fish & Wildlife Conservation Commission that is evaluating the orientation response of sea turtle hatchlings to physical cues on nesting beaches. One of the necessary components to achieve the project’s goal is quantified hatchling orientation data. 

Last week, Dr. Hirama trained SCCF volunteers to collect data about hatchling tracks using a phone app as pictured here. This study will make it possible to understand the relationships between hatchling orientation and the beach environment, including man-made lights.



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