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Beach Patrols

Nightly patrols of nesting beaches are conducted from June 1st through October 31st. Three separate patrols groups, each covering different beaches on the west and south coast set out around 8:00pm in order to document all nesting activity. BSTP staff not only look for the nesting females when they come out of the sea to nest, but also for any signs, such as tracks, to indicate that a female turtle was on the beach.

Recording Turtle Information (Monitoring)

Weighing a Turtle The index beach

If the nesting female has already left the beach, the patrol group will document what type of activity took place. Was the female able to nest? Did she attempt to nest, but was unsuccessful? These questions can usually be answered by looking at the tracks and the pattern of sand disturbance.

If the female is present, BSTP staff members read her tag numbers, or give her new tags if she does not have any. Long term tagging programmes provide unique information on the distribution and abundance of gravid females, as well as estimates on inter-nesting intervals and remigration intervals.  Measurements of her carapace are taken, along with measurements and site observations as to where she nested on the beach.

 
It is important that the site where a female has nested will be safe for the approximate 60-day incubation period. If the eggs will not be safe, possibly due to washout by high seas or if it is in an area of high foot or vehicular traffic, the BSTP staff will carefully relocate them to a safer area.
Most hatchlings emerge during the night. After the hatchlings have emerged, patrol groups excavate the nests.  The nest contents are examined and counted in order to determine hatching success.  Hatchlings are strongly attracted to bright light and can become disoriented by artificial lights. If this is the case, the BSTP staff will collect and release them on a darker section of the beach.

By documenting all nesting activity around the island, the Barbados Sea Turtle Project is able to monitor the populations of Hawksbills, Greens and Leatherbacks that use Barbados’ beaches in order to nest.

Satellite Telemetry

Four post-nesting hawksbill turtles (Eretmochelys imbricata) were fitted with satellite transmitters in Barbados during the 1998 nesting season. This activity was part of a Caribbean-wide hawksbill research satellite tracking project to investigate whether adult females may undertake long-distance migrations between their nesting and foraging sites.

The four study animals left Barbados waters immediately following their final nesting activity for the season and travelled for periods of between 7 and 18 days to reach foraging grounds in Dominica, Grenada, Trinidad, and Venezuela. Straight-line travel distances ranged from 200 to 435 km. 

The data indicate that adult females nesting in Barbados, where they are fully protected, may spend the majority of their lives in waters where they are only partially protected or unprotected.

Turtle 8208, affectionately know as "Lotus", returned to Barbados from her foraging grounds in Grenada for the 2001 nesting season. BSTP staff witnessed her first nest on July 11, 2001. During this time, the transmitter was removed from "Lotus" and subsequently returned to the factory for replacement of batteries and to be refurbished.

The transmitter was returned to the BSTP and was applied onto a late nesting female on October 27, 2001. This turtle, named "Jen", nested once more in Barbados on November 11, 2001. Soon after nesting she began her migration back to a feeding ground. The Barbados Sea Turtle Project was able to track her northwesterly migration where she seems to have settled off of the coast of Marie Galante, a small island off of and part of Guadeloupe. Hopefully here, "Jen" the hawksbill will be safe until she returns to Barbados to nest again in years to come. Our most distant track was that of a female who nested at Bath beach, then travelled back to her Dominican Republic foraging ground.

 

Genetic Analysis

Genetic analyses have shown that the nesting populations of  hawksbills in the Caribbean are highly structured (Bass et al., 1996), while the foraging grounds are largely mixed (Díaz-Fernández et al., 1999). The significance of this result is that it demonstrates that animals mix with others from all over the region on foraging grounds, but when they become breeding adults they recruit back to their natal beaches. It also suggests that there is relatively little recruitment to a given island from other colonies in the region. This emphasises the need to protect the remaining nesting population in Barbados in order to ensure the long term survival of the species in this country.  Equally important (also suggested by satellite telemetry data) is the commitment of Barbados to work with range states in order to ensure the success of domestic conservation measures.

  

In-water Tagging

Three days a week BSTP staff go SCUBA diving in order to catch juvenile hawksbill sea turtles that reside on the reefs along the west coast of Barbados. Upon capture they are subsequently brought up to the dive boat where data is collected. The turtles are:

Underwater Photo: Micaela Scialanga

 

  • measured

  • weighed

  • tagged

  • given an identification number on their shell

  • released

Over 600 hawksbill and green turtles have been tagged and identified by the BSTP since mid 1998 when the in water tagging programme began.  If a turtle is re-seen at an interval of 6 months or more, it is re-captured for measurement and the painted number is touched up for ongoing study.  Subsequent recaptures and sightings provide information on growth rates, the movements of turtles between reefs, and where the most important foraging habitats are off of the Barbados coastline (reef systems and sea grass beds).

 

 
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© Copyright 2006. All rights reserved. Contact: Prof. Julia Horrocks
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