Research and Monitoring of Bonaire’s Sea Turtles: 2013
Sea Turtle Conservation Bonaire (STCB) was initiated in the early 1990s to protect the island’s marine turtle populations. Our current research and monitoring efforts, which were standardized more than a decade ago, include monitoring important nesting beaches around Bonaire, conducting intensive in-water netting and snorkel surveys (capture-markrecapture), and tracking post-breeding turtle migration using satellite telemetry. These techniques provide us with a better understanding of Bonaire sea turtles’ breeding success, abundance, health, residency duration, habitat quality, growth rates, migratory paths, distant feeding grounds, and threats.
During the 2013 season, we observed 77 nests at our index beach on Klein Bonaire. Total hawksbill (54) and loggerhead (23) nests documented there were similar to numbers observed during recent years. Across Bonaire and Klein Bonaire, we observed four species crawling 231 times, including 126 confirmed or suspected nests. Because our coverage of the island was not complete and weather conditions can quickly obscure crawls, these nation-wide figures represent the minimum number of crawls and nests that occurred on Bonaire and Klein Bonaire during 2013. As in previous years, nesting activities peaked during June through August. Thirty-four green turtle nests and a single leatherback nest were recorded in northeastern Bonaire, whereas hawksbills and loggerheads primarily nested on Klein Bonaire and beaches of southern Bonaire.
We observed green turtles and hawksbills along the west coast of Bonaire, around Klein Bonaire, and adjacent to Lac during snorkel surveys. Green turtle sightings were particularly high near Lac, and netting surveys also suggested large aggregations of green turtles in shallow, sea grass foraging sites of Lac. Green turtles documented there were larger than individuals reported elsewhere in Bonaire.
Five green turtles tagged in 2003 and 2006 were reported in Nicaragua’s sea turtle harvest, valuable data about sea turtle movements which complement our satellite tracking program. Unfortunately, incidences of fibropapillomatosis among green turtles were more widespread in 2013 than recent seasons.
In 2013, we tracked a post-nesting female hawksbill turtle using satellite telemetry from Bonaire to Honduras over a period of 85 days. The turtle passed through six national territorial waters, swimming over 5,000 km (3,000 mi) to reach a general area proven to be important foraging grounds for Bonaire breeding turtles.
We also outfitted a hawksbill with a datalogger to gather information on hawksbill habitat use and behaviors. The device, which collects GPS locations and depth information, was retrieved in July, 2013. Preliminary results are consistent with previously deployed dataloggers, indicating regular movements in and out of Lac Bay.
Sadly, we recorded 18 turtles stranded during 2013, 12 of which were found dead or had to be euthanized.
We will be undertaking several new research initiatives in the year ahead, including using our tagging data to estimate the total population of sea turtles using Bonaire’s waters (which will help to inform management policy) and to estimate the tremendous growth rates of green turtles in Lac, as well as reviewing our monitoring program to ensure that protocols are as efficient as possible.