A Global Snapshot of Loggerheads and Leatherbacks
By BRIAN J. HUTCHINSON and ALEC HUTCHINSON
“The Unsolved Mysteries of Sea Turtles” underscores one of the greatest challenges that conservationists face in preventing extinctions: insufficient data.
Scientists the world over are working to meet this challenge in their research efforts. The SWOT Team with its global perspective is identifying, collecting, and presenting sea turtle data from around the world—an effort that will ultimately enable the conservation community to take collective actions when sea turtle populations decline and to focus resources on the highest priorities.
The inaugural volume of SWOT Report and its presentation of worldwide leatherback nesting beaches was the first step. With plans to tackle one species at a time, one year at a time, the SWOT Team has addressed its next priority for global data collection: the loggerhead sea turtle.
Like leatherbacks, loggerheads are found in almost every ocean. Both species are threatened nearly everywhere they are found by hazards at their nesting beaches and during transoceanic journeys. Listed as Endangered on the IUCN Red List of Threatened Species, loggerheads face threats including coastal development, fisheries bycatch, direct hunting (for eggs and meat), pollution, and climate change.
The following two maps document just one slice of the long and complex lives of some of Earth’s most widely ranging and mysterious animals. Here we present the loggerhead and leatherback nesting beaches of the world, with the number of nests laid at each site during the 2005 nesting season. Each dot represents the contributions of the patrollers who walk each beach, collecting data day and night, as well as the institutions and donors who make these efforts possible. As such, every data point is numbered to correspond with a citation that acknowledges its source. The featured first-year loggerhead data are printed with comprehensive citations, while leatherback data citations are abbreviated. Both sets of data are available in full on the SWOT Web site at www.SeaTurtleStatus.org.
The global snapshot of loggerhead nesting in this report is the first presentation of its kind. The leatherback map presents the SWOT Team’s second year of leatherback data, building on the inaugural data presented in SWOT Report, Volume I. In total, the 166 SWOT Team data providers have documented 203 loggerhead beaches from 68 sources in 45 countries, and 204 leatherback beaches from 76 sources in 52 countries.
These maps were developed under the guidance of the SWOT Scientific Advisory Board that has agreed on specific protocols for the development of the maps. The number of nests documented at each beach is used as the display value for each data point. In areas where only a count of nesting females was available, that count was used to estimate the number of nests by applying a conversion—the average number of nests laid per female, per season (the clutch frequency)— from the geographically closest available beach during the same nesting season. Recognizing that these conversions are imperfect, we have chosen to report only the original count values in the citations.
SWOT Team members have also contributed information on the procedures used to gather their data, so that each piece of data may be evaluated for its completeness. Specifically, in each citation we present the techniques used for beach monitoring, the period of beach monitoring, the period of the full nesting season, and the peak period of nesting.
The following maps represent a momentous second step into the future of data sharing and sea turtle conservation planning. With hawksbill nesting sites of the world on the SWOT Team’s horizon, we continue toward our vision of presenting a continually contemporized view of all seven species of sea turtles across the globe.
Worldwide Loggerhead Nesting Sites 2005 (data citations) | SWOT Report, vol. II (2007).
Worldwide Leatherback Nesting Sites 2005 (data citations) | SWOT Report, vol. II (2007).
This article originally appeared in SWOT Report, vol. 2 (2007). Click here to download the entire article as a PDF.