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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.
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.
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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. |
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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. |
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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. |
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Satellite Telemetry |
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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.
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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. |
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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. |
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Genetic
Analysis |
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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.
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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:
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Underwater Photo: Micaela Scialanga
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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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