Active Projects

Caught on Camera: The secret lives and foraging behaviors of loggerhead sea turtles

Have you ever been curious what sea turtles do when we’re not around? Or how about what they do to avoid us when we are around? For the next year starting in Summer 2021, we are hooking up loggerhead sea turtles off Crystal River, Florida with Paralenz Vaquita dive cameras to see the world from their perspective. The cameras will stay attached for 3-4 hours, after which they will pop off, float to the surface, and transmit a VHF radio signal, allowing us to retrieve the footage.

Through this project, we hope to gain a better understanding of the turtles’:

  • Dive patterns,
  • Foraging behaviors,
  • Habitat preferences,
  • Interactions with other organisms (e.g., other turtles, dolphins, sharks, fishes), and
  • Response behaviors when exposed to humans (e.g., snorkelers, boats anchored or transiting)

This footage will also help us:

  • Quantify the frequency of exposure to numerous threats (e.g., plastic pollution, boat strikes), and
  • Fill in critical knowledge gaps in sea turtle and benthic ecology
    • How does prey selection impact tissue stable isotope signatures?
    • How do foraging mechanics relate to epibiont assemblage patterns?
    • Can foraging-epibiont patterns partially explain the meiofauna paradox – the counter-intuitively wide dispersal of benthic microorganisms?

Funding sources for this project include:

Wave exposure and inundation of sea turtle nesting beaches

Inundation and nest erosion from wave exposure, storm surge, and sea level rise are major threats to sea turtle nests – causing mortality as well as potential changes in hatchling size, morphology, locomotor function, and sex. Female turtles use several environmental cues when deciding where to nest such as beach slope, tide height, and distance from the water to reduce the chances of wave exposure. However, waves are still a common problem and increasing storm intensity and coastal development only exacerbate the issue. Identifying where and under what conditions wave exposure becomes a problem, and deciding what action to take (if any), is a common issue for sea turtle managers. For example, before we can consider any management action or intervention ranging from beach preservation to nest relocation, we need to know:

  • At what frequency or duration of exposure does wave wash-over cause significant harm to developing turtles?
  • Do these exposure thresholds vary with the developmental stage of the embryo?
  • How does this tolerance (or lack thereof) vary across species and populations?
  • What are the benefits of non-lethal levels of wave exposure, including reduced incubation temperatures, increased male hatchling production, large body sizes, and/or faster crawling speeds?
  • Would relocating nests introduce other threats which may cause as much (or greater) impact than wave exposure in their current location, such as hyperthermia, increased female hatchling production in a female-dominant population, desiccation, and increased predation or orientation?
  • How is wave exposure likely to change in the near future due to coastal development, armoring, beach erosion, hurricane frequency and strength, and sea level rise?
  • How may sea turtles naturally adjust their nesting behaviors to combat these changing beach conditions?

To help inform conservation initiatives to combat this threat, we can use beach elevation data, nest location and productivity data, and wave runup modeling to:

  • 1) identify the reduction in loggerhead sea turtle hatchling production caused by wave exposure, and
  • 2) map out which beaches represent priority areas for conservation initiatives.
Map of wave exposure along a portion of the St Joseph Peninsula shoreline
Proportion of wave exposure along a stretch of the St Joseph Peninsula shoreline from 2016 to 2019. Loggerhead sea turtle nests laid during this time were typically above the most frequently exposed portions of the beach.

Following these modeling exercises, we can collect in situ information such as the frequency of wave exposure, its duration, hatchling production, and other data to close the information gaps and better inform management decisions. For example, St George Island was identified as a priority area for wave exposure impacts based on wave runup mapping in the Florida Panhandle. In 2021, we will be monitoring wave exposure and inundation across the nesting beach throughout the nesting season to begin describing embryonic tolerance to these threats.

Funding sources for this project include:

Publications in this project and related literature:

Understanding the exposure of sea turtles to vessels: Determining the potential impacts of vessel strikes in South Florida

The Florida Fish and Wildlife Conservation Commission recently identified 8 inlets throughout the state as sea turtle-vessel strike hotspots (Foley et al. 2019). In October 2018, the Florida State University Marine Turtle, Research, Ecology, and Conservation Group convened a workshop in Tallahassee, Florida, with relevant stakeholders including state wildlife managers, law enforcement, rehabilitation centers, and academics to identify conservation actions which may be effective in reducing sea turtle-vessel strike mortality. Such actions could include reducing speed along designated paths (comparable to the existing manatee speed zones throughout Florida), avoiding or temporarily closing areas immediately offshore high-density nesting beaches, and an educational campaign to alter boaters to the presence of sea turtles in the area and impacts of sea turtle-vessel interactions both to the turtle and the vessel.

Student conducting a boater survey

These conservation actions and the sentiments of the boating community about their theoretical enforcement were evaluated with social surveys at 8 public boat ramps throughout the St. Lucie Inlet region (see the Publications page to request a copy of the report and the published journal article). This region is home to many species of sea turtles including loggerheads, greens, Kemp’s ridleys, and leatherbacks – hawksbills and even an olive ridley have been reported in the area as well!

Following the social surveys, we conducted a series of in-water surveys with Inwater Research Group to identify areas of significant overlap between vessel traffic and sea turtle habitat use throughout the inlet and nearby waterways which may benefit from conservation actions. Check out the publication in Marine Policy – https://www.sciencedirect.com/science/article/abs/pii/S0308597X21000828

Funding sources for this project include:

Publications in this project and related literature:

Integrative assessment of a loggerhead foraging aggregation in Crystal River, Florida

A student with a Kemps ridley sea turtle

For the past several years, the Florida State Marine Turtle Research, Ecology, and Conservation Group has been conducting regular in-water sea turtle surveys in the St. Martins Marsh Aquatic Preserve and the Chassahowitzka National Wildlife Refuge offshore between the Crystal and Homosassa Rivers. We regularly capture loggerhead, green, and Kemp’s ridley sea turtles for health and morphometric assessments, biopsies for genetic and stable isotope analysis, and tagging to understand population dynamics. This extensive monitoring allows us to describe habitat use patterns across the three species and between seasons, including changes in those patterns due to human activities such as the recreational scallop fishery (Wildermann et al. 2018).

A new twist for the 2021 season will be the deployment of turtle-mounted cameras (see above)! These cameras will record behavioral and dive data to help us better understand foraging and disturbance-evasion activities for loggerhead sea turtles. I’m sure we are also in for a few surprises!

We will be continuing our sampling for another year, so if you see us out on the water, say “Hello!” and keep an eye out for turtles!

Funding sources for this project include:

Publications in this project and related literature:

Collaborations and Project Assistance

In addition to my own research, as a member of the FSU Marine Turtle Research, Ecology, and Conservation Group, I have the pleasure of assisting my lab-mates and other researchers in their projects. These projects have included …

  • Validation of the use of stereo-video imaging for in-water sea turtle morphometric data collection in collaboration with the University of West Florida
  • Evaluation of hatchery management actions on hatchling productivity in San Pancho, Mexico with the Science Exchange Internship Program and Grupo Ecologico de la Costa Verde
  • A global survey of microplastic pollution at sea turtle nesting beaches in collaboration with the University of Exeter
  • In-water trawl surveys on the R/V Georgia Bulldog with the South Carolina Department of Natural Resources to conduct population surveys and morphometrics/health assessments
  • Night surveys on St. George Island, Florida to collect epibiont samples and conduct morphometrics/health assessments
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