Index Nesting Beach Survey Totals (1989-2016)

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.

Loggerhead Nesting-CherylSanchez

    A loggerhead sea turtle nesting early in the morning throws sand over a nest, concealing her eggs, on an index beach in Brevard County. The greatest majority of loggerhead nesting occurs at night but sometimes surveyors encounter females still on the beach early in the morning.
Photo credit: Cheryl L. Sanchez

Since 1989, the Fish and Wildlife Research Institute (FWRI) has 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 a standardized data-collection protocol 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 following the index-survey protocol.

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 329 kilometers of nesting beach (204 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). Surveyors record nests and nesting attempts by species, nest location and date. Index nest counts represent approximately 60 percent of known loggerhead nesting in Florida, 70 percent of known green turtle nesting and 36 percent of known leatherback nesting.

Loggerhead Nests

Observed loggerhead nest counts on Florida’s 27 core index beaches have varied greatly since the beginning of the program in 1989, reaching a minimum of 28,074 in 2007 and a maximum of 65,807 nests in 2016. These numbers do not represent Florida’s total annual nest counts because they are collected only on a subset of Florida’s beaches    (27 out of 215 beaches) and only during a 109-day time window (15 May – 31 August). The standardized data collection approach used by the INBS program is designed to examine nesting trends. Nest counts on Florida’s 27 core index beaches reveal a complex nesting pattern for the loggerhead turtle with multiple changes in trend direction.  More years are needed to understand whether loggerhead nesting follows a cyclic pattern.

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Annual loggerhead nest counts on core index beaches. From 1989 through 2016, annual counts ranged from 28,074 to 65,807 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 and in more recent years.

 

Index beaches in the Florida Panhandle, which are not part of the set of core beaches, had the highest loggerhead nest counts in 2016 since these surveys to detect trends began in that area in 1997. Three additional beaches joined the Index program in the Panhandle in 2016: St. George Island State Park, St. Joseph Peninsula and Gulf Island National Seashore.

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Annual loggerhead nest counts on Florida Panhandle index beaches.

 

Concern over declines in annual loggerhead nest counts (observed between 1999 and 2007) 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 2016.


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 loggerheads that nest on the same beaches. In 2016, green turtle nest counts on the 27 core index beaches were dramatically lower than in 2015 (the record high year since the beginning of the INBS program). The low nest numbers were expected because green turtles tend to follow a two-year reproductive cycle and typically, there are wide year-to-year fluctuations in the number of nests recorded.

  

green turtle nesting trends graph, 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 319 leatherback nests on the 27 core index beaches in 2016, the lowest number of nests reported since 2008. 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 over the period of monitoring.

LeatherbackNests2016
Annual leatherback nest counts on core Index beaches. From 1989 through 2016, leatherback nests at core index beaches varied from a minimum of 30 nests in 1990 to a maximum of 657 in 2014.


FWC Facts:
The secretive little pygmy sunfish is not a true sunfish and may be more related to sticklebacks and pipefishes.

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