Project Title: Population Assessment of Sea Turtles in Lake Worth Lagoon
Project Manager: Paul Davis
Organization: Palm Beach County (Florida Government)
Grant Amount: $19,000.00
Completion Date: 2007-05-19
Summary: Lake Worth Lagoon (LWL) is a 20 mile long body of water located just west of the Atlantic Ocean along the coast of Palm Beach County, Florida. The lagoon was historically a freshwater lake, but it has been severely altered by human activities since the late 1800s. Today, the LWL is a moderately polluted estuarine waterway that receives ocean water from two man-made inlets. Palm Beach County has extensive monitoring of its high density nesting beaches, yet little is known about the sea turtles utilizing the LWL. The Lake Worth Lagoon Management Plan recommends evaluating sea turtle populations in the lagoon to provide information that will guide lagoon restoration management decisions. This information will also be useful in comparing this population with other inshore Florida populations. Five species of sea turtle have been reported in the lagoon, largely from stranding reports, incidental take from dredges, and anecdotal observations. Sighting data collected during aerial manatee surveys exists, but this information is ancillary and not species specific. This project will collect data primarily by netting which will be augmented by visual observations. The five main objectives of this project are: 1. Obtain baseline data on species abundance, size frequencies and sex ratios; 2. Determine Catch per Unit Effort (CPUE) at specific sites in the LWL; 3. Document the prevalence of fibropapillomatosis (FP), a potentially deadly disease that occurs at a high frequency among sea turtles in Indian River Lagoon and Florida Bay. 4. Obtain blood samples for genetic, sex ratio and disease analysis. 5. Determine habitat preference of sea turtles within the LWL by collecting GPS coordinates of sighting and captures and overlaying this with existing habitat data.
Results: Four sampling events were conducted during this project. Twenty eight visual transects were conducted, covering 176.96 km of the LWL. A total of 52 green sea turtles were sighted on transect, generating a sighting rate of 0.29 green sea turtles/km. An additional 71 sea turtles were spotted off transect, primarily during netting activities. Tangle nets were set twenty nine times in the vicinity of Little Munyon Island. Twenty six green sea turtles and one loggerhead have been captured during netting activities, generating a Catch per Unit Effort (CPUE) of 3.01 sea turtles per km/net hour. The overall FP rate in captured green sea turtles is 53.8%. Twenty five blood samples and 12 dietary samples have been collected. (Author: Paul Davis)