Stapleton,S.

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.

Date
2014
Data type
Research report
Theme
Research and monitoring
Report number
Technical Report 2013
Geographic location
Bonaire

Research and Monitoring of Bonaire ’s Sea Turtles: 2014 Technical Report

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 nesting beaches around Bonaire, conducting intensive in-water netting and snorkel surveys (capture-mark-recapture), and tracking post-breeding migration using satellite telemetry. These techniques provide us with a better understanding of Bonaire sea turtles’ breeding success, abundance, health, growth rates, migratory paths and distant feeding grounds, residency duration, habitat quality, and threats.
During the 2014 season, we recorded 63 nests at our index beach on Klein Bonaire. Total hawksbill (45) and loggerhead (18) nests documented there were similar to numbers observed during recent years. Across Bonaire and Klein Bonaire, we observed three species crawling 260 times, including 83 confirmed or suspected nests. Only two green turtle nests were recorded in northeastern Bonaire, whereas hawksbills and loggerheads exclusively nested on Klein Bonaire and the beaches of southern Bonaire. Total nesting activities peaked during June through August, with nesting extending through December.
We documented a much higher number of false crawls (unsuccessful nesting attempts) for both hawksbills and loggerheads in 2014 than in 2013. This phenomenon may result from a small number of individuals which were inefficient nesters (i.e., false crawled multiple times before successfully laying a nest), disturbance to turtles during nesting, and / or indicate deterioration in the quality of particular nesting sites, perhaps due to factors such as removal of vegetation. Estimates of clutch size and hatch success suggest that nearly 8,700 turtles hatched on the beaches of Bonaire and Klein Bonaire during 2014, including some 6,300 hawksbills, 2,200 loggerheads and 160 green turtles.
During in-water snorkel surveys, we observed and captured green turtles and hawksbills in all regions sampled, including Klein Bonaire, along the west coast of Bonaire, and near the reef bordering Lac. Netting in Lac and Lagoen resulted in a record number of captures during 2014, primarily green turtles. The aggregation of green turtles near Lac remains much larger than sites along the west coast, and greens captured there were bigger than conspecifics elsewhere, perhaps a result of the composition and high densities of sea grasses in Lac. Analysis of the 2013 and 2014 capture data from Lac indicates that netting during the second week of a two-week session is less efficient at capturing turtles. These results suggest that conducting netting sessions during non-consecutive weeks may be a more effective sampling strategy.
We received reports from the WIDECAST Marine Turtle Tagging Centre of 5 green turtles caught in nets by Nicaraguan fishers in the sea turtle harvest during the past 18 months. These recoveries provide invaluable information about international movements and migratory behaviors. The prevalence of fibropapillomatosis (FP) among green turtles captured in and near Lac again increased in 2014, as roughly one-third of all captures were observed with external tumors. However, we recaptured two green turtles that were previously treated to eliminate the fibropapilloma tumors. In both cases, the results were positive, perhaps suggesting that removing tumors via surgery or ligation can improve the health of individual turtles and reduce the incidence of FP in Lac.
 
Retreived from http://www.bonaireturtles.org on April 13, 2015

Date
2014
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire

Research and Monitoring Report 2013 - Sea Turtle Conservation 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 
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. 
 

Date
2014
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire