Index Nesting Beach Survey Totals (1989-2015)

The Florida Index Nesting Beach Survey records sea turtle nest counts on a standardized set of index beaches. Researchers use the annual survey to determine nesting trends.

Since 1989, the Fish and Wildlife Research Institute (FWRI) coordinated the Index Nesting Beach Survey, a detailed sea turtle nesting-trend monitoring program conducted in conjunction with the Statewide Nesting Beach Survey. The index survey uses standardized data-collection criteria to measure seasonal nesting and allow accurate comparisons between beaches and between years. Consistent effort by location, fixed dates, and specialized annual training of beach surveyors make the index program suited to these trend assessments. Approximately 30 percent of Florida's beach length is surveyed under index-survey criteria.

FWRI coordinates data collection through a network of surveyors, including federal, state and local park personnel; other government agency personnel; members of conservation organizations; university researchers; and private citizens. FWRI staff provide annual training to beach surveyors and compile data from the annual surveys.

At a core set of index beaches monitored since 1989, trained surveyors monitor 320 kilometers of nesting beach (nearly 200 miles) divided into zones that average 0.8 kilometers (approximately a half mile) in length. These core index beaches represent the Atlantic and Gulf coasts of peninsular Florida. Beach surveyors monitor core index zones daily during a 109-day sea turtle index-nesting season (May 15 through August 31). Researchers record nests and nesting attempts by species, nest location and date. Index nest counts represent approximately 66 percent of known loggerhead nesting in Florida, 68 percent of known green turtle nesting and 35 percent of known leatherback nesting.

Nesting loggerhead
A loggerhead sea turtle throws sand over a nest to conceal her eggs.


Loggerhead Nests

Observed loggerhead nest counts on Florida’s 26 core index beaches varied from a peak of 59,918 in 1998 to a low of 28,074 in 2007. Since 2007, there has been a general increase in nest counts. This increase includes the most recent nesting season in 2015, a year in which nest counts (52,647) were higher than in the last two year (2013-2014) but lower than 2012 (the second record high year since the beginning of the INBS program).

Index beaches in the Florida Panhandle, which are not part of the set of core beaches, had higher loggerhead nest counts in 2015 compared to the previous two years; the 2015 count was the 3rd highest on Florida Panhandle index beaches since these surveys to detect trends began in that area in 1997.


Annual loggerhead nest counts on core index beaches, caption below
Annual loggerhead nest counts on core index beaches. From 1989 through 2015, annual counts ranged from 28,074 to 59,918 nests. Survey effort remained nearly identical. These data represent peninsular Florida and exclude an additional set of beaches in the Florida Panhandle and southwest coast that were added to the program in 1997.


Graph of annual loggerhead nest counts, caption below

Annual loggerhead nest counts on Florida Panhandle index beaches.



Concern over declines in annual loggerhead nest counts prompted researchers to conduct a detailed analysis of the species’ nesting trends since 1989. Download a 2009 journal article about the research:
Decreasing Annual Nest Counts in a Globally Important Loggerhead Sea Turtle Population.

The article Trends in Nesting by Florida Loggerheads includes survey data through 2015.

Green Turtle Nests

Green turtle nest counts have increased approximately one hundredfold since counts began in 1989 – a trend that differs dramatically from that of the loggerhead. In 2015, green turtle nest counts reached a new record high with 27,975 nests laid on the 26 core INBS beaches during the 109-day sea turtle index-nesting season. Green turtles set three record highs in 2011, 2013 and 2015. Nest counts in 2015 were slightly higher than the 2013 counts which was more than twice the counts from 2011 (the 3rd record high year). Nesting green turtles tend to follow a two-year reproductive cycle and there typically are wide year-to-year fluctuations in the number of nests recorded.


graph showing green turtle nest counts, caption below
Annual green turtle nest counts on core Index beaches. Since 1989, nest counts have ranged from 267 to 27,975, peaking in 2015. Numbers show a mostly biennial pattern of fluctuation, with three records set on 2011, 2013 and 2015.


Leatherback Nests

Surveyors counted 489 leatherback nests on core index beaches in 2015. These counts do not include leatherback nesting at the beginning of the season before May 15, nor do they represent all the beaches in Florida where leatherbacks nest; however, the index provided by these counts remains a representative reflection of trends. Similar to nest counts for green turtles, leatherback nest counts have been increasing exponentially.

graph showing leatherback nest counts, caption below
Annual leatherback nest counts on core Index beaches. From 1989 through 2015, leatherback nests at core index beaches numbered from 27 to 641.

FWC Facts:
Sea turtles range in size from the 75- to 100-pound Kemp’s ridley to the 1,300-pound, 8-foot-long leatherback.

Learn More at AskFWC