Long-Term Monitoring Program Reveals a Continuing Loggerhead Decline, Increases in Green Turtle and Leatherback Nesting

The steep decline in loggerhead nest numbers has followed a modest increase that occurred between 1989 and 1998. Between 1989 and 2007, the overall trend in loggerhead nesting is down approximately 37 percent. The index nesting data used in this analysis comprise nest counts made by hundreds of participants who survey turtle tracks and nests at certain Florida beaches. The participants hold a Florida Marine Turtle Permit and are specially trained in sea turtle nest identification. Participants are also required to follow a rigorous protocol to ensure nest counts reveal unbiased trends. Scientists at FWC’s Fish and Wildlife Research Institute coordinate the nest counts.

Nest counts for green turtles and leatherback turtles in Florida show an opposite trend over the same period.  In 2007, the number of green turtle and leatherback nests on index beaches was the highest since the trend-monitoring program began in 1989. These two species nest on many of the same beaches in Florida as the loggerhead, but in much smaller numbers.   

Follow this link for more information on how nesting-trend data are collected, and for trends in nesting by green turtles and leatherback turtles.

Florida accounts for more than 90 percent of the loggerhead nesting in the United States with a nesting aggregation considered to be one of the two largest remaining in the world.  Although loggerhead sea turtles nest at many locations around the world, nearly 90 percent of the world’s population is believed to nest on the beaches of Florida and Oman (on the Arabian Peninsula). Data collected during the 2007 season indicate the lowest nesting levels in Florida in the 19-year history of this monitoring program.

Loggerhead sea turtle deaths in Florida, as indicated by strandings (which are dead or moribund turtles found on the beach or in the water) have more than doubled during the past decade based on information from the FWC’s Fish and Wildlife Research Institute, Sea Turtle Stranding and Salvage Network database.  Loggerheads have many threats to their survival. Artificial lighting on nesting beaches causes hatchlings from nests to crawl inland rather than toward the water. On developed beaches, coastal armoring meant to protect buildings from erosion has resulted in the loss of nesting habitat near natural dunes. Throughout the state’s waters, collisions with boats constitute the most common identifiable cause of trauma in sea turtles that wash up dead on Florida beaches. 

Florida has been subject to numerous hurricanes in recent years, but these storm events have a very limited effect on nesting activity of adult female turtles.  Because loggerheads hatched on Florida beaches require some 20–30 years to reach maturity, recent storm impacts on turtle populations would not appear for many years.  Moreover, hurricane impacts to nests tend to be localized and often occur after the main hatching season for the loggerhead is over.

Some threats to Florida’s loggerheads occur far from the state’s waters and beaches. During the approximately 30 years it takes for a loggerhead sea turtle to mature, a turtle is likely to have traveled widely in the Atlantic Ocean basin where major sources of incidental mortality occur. These threats include drowning in fishing trawls that are pulled to catch shrimp, and hooking and entanglement by open-ocean longlines set to catch sharks, tunas, and swordfish.  

Occasionally, mass strandings of dead loggerheads occur without clear evidence revealing what disease, toxin, or event was the cause.  In Florida, FWC is continuing efforts to manage errant lighting that could mislead and result in hatchling sea turtle mortalities on developed beaches.  Although Florida’s booming human population and coastal growth are challenges for sea turtle protection, FWC has expanded efforts to guide coastal construction practices, regulate commercial fishing activities, and facilitate the rescue and rehabilitation of sick and injured sea turtles. 

In order to help protect and manage Florida’s sea turtles outside of Florida waters, FWC provides nesting data to the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service and the U.S. Fish and Wildlife Service. Both federal agencies have management oversight beyond Florida's jurisdiction. Floridians interested in doing their part to help Florida’s sea turtles can learn more about sea turtles and threats to their survival by visiting the Sea Turtles section.