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Expedition report: Gentle giants: Protecting leatherback sea turtles through direct conservation action on the Caribbean coast of Costa Rica (May 2017)

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Abstract and Figures

Abstract From 27 February until 31 October 2017, nesting activities of leatherback turtle (Dermochelys coriacea), green turtle (Chelonia mydas), hawksbill turtle (Eretmochelys imbricata) and loggerhead turtle (Caretta caretta) were recorded on Pacuare beach, on the Caribbean coast of Limon province, Costa Rica. 279 leatherback nests, 72 green turtle nests, 10 hawksbill nests and 1 loggerhead nest were logged. 200 nests were relocated into a custom-built hatchery where they were guarded 24/7, 19 were incubated ex situ and 8 were relocated to a safe place on the beach. The emergence success of the nests of leatherback turtle was 58.77% (SD = 24.77, n = 162), green turtle 71.1% (SD = 23.92, n = 53), and hawksbill turtle 71.9% (SD = 23.74, n = 8). The single loggerhead nest had an emergence success of 61.53%. From all the saved nests, a total of 12,591 neonates were released (leatherback 7,349, green turtle 4,262, hawksbill 900, loggerhead 80). 10 green and 5 hawksbill adult turtles we recorded to have been killed by poachers; the true number is likely to be higher. Despite this, the number of turtles killed is the same or lower than in previous seasons. An average of 75% of turtle nests across four species (leatherback 58%, green 76%, hawksbill 67%, loggerhead 100%) were saved as a result of the project’s beach patrol and direct conservation actions. This percentage of saved nests is the highest since the project started in 2012 and should be celebrated as a major success in sea turtle conservation by LAST, the local community, Biosphere Expeditions and other partners involved in the project. Data recorded since 2012 suggest that nesting activity for leatherback and hawksbill remains stable in Pacuare. However, this should be treated with caution since the life cycle of these animals is slow. LAST and Biosphere Expeditions will continue to run this project and make various recommendations for improvements in this report. The high number of poachers, as well as the nest and adult poaching rates, remain a serious concern. This project continues to fight a successful battle with the poachers with a high this year of 75% of nests saved. If the national authorities tasked with nature protection and law enforcement were to join efforts in turtle conservation properly, and thereI are encouraging signs of this starting to happen, then in the opinion of the authors, combined actions by NGOs and state authorities will have a high chance of success of bringing poaching down to levels below 10%, which would turn this project from extinction prevention into population recovery. Resumen Desde el 27 de febrero hasta el 31 de octubre se contabilizaron las actividades de anidación de la tortuga baula (Dermochelys coriacea), tortuga verde (Chelonia mydas), tortuga carey (Eretmochelys imbricata) y tortuga cabezona (Caretta caretta) en Playa Pacuare en el Caribe de la Provincia de Limón, Costa Rica. Se registraron 279 nidos de tortuga baula, 72 nidos de tortuga verde, 10 nidos de tortuga carey y un nido de tortuga cabezona. 200 nidadas fueron trasladas al vivero donde fueron incubadas y protegidas 24/7, 19 fueron incubadas ex situ en hieleras de estereofón (mientras el vivero estaba en construcción) y ocho fueron relocalizadas en zonas seguras de la playa (también cuando el vivero estaba en construcción). El porcentaje de emergencia para las nidadas exhumadas de tortuga baula fue de 58.77% (SD.= 24.77, n = 162), 71.1% (SD = 23.92, n = 53) para tortuga verde, 71.9% (SD = 23.74, n = 8) para tortuga carey y el único nido de tortuga cabezona presentó 61.53%. Del total de las nidadas salvadas se liberó un aproximado de 12,591 neonatos (7, 349 fueron de tortuga baula, 4,262 de tortuga verde, 900 de tortuga carey y 80 de tortuga cabezona). Se registró la matanza de 10 hembras de tortuga verde y 5 hembras de tortuga carey a manos de los cazadores furtivos pero se calcula que el número real es aún mayor. Se estima que el número de tortugas asesinadas es igual o menor que en las temporadas pasadas. El 75% de los nidos de las cuatro especies de tortugas marinas (baula 58%, tortuga verde 76%, tortuga carey 67%, tortuga cabezona 100%) fueron salvados como resultado del patrullaje de la playa por parte del proyecto y las acciones de conservación implementadas. El porcentaje de nidos salvados es el más alto obtenido desde inicios del proyecto en el año 2012 y debe ser celebrado como el mayor logro alcanzado con respecto a la conservación de las tortugas marinas por parte de LAST, la comunidad local, Biosphere Expedition y demás personas involucradas en el proyecto. Los datos obtenidos desde el año 2012 nos demuestran que las actividades de anidación de la tortuga baula y la tortuga carey permanecen estables en Pacuare. En todo caso, debido a que el ciclo de vida de éstos animales es lento, se debe seguir con precaución con las estrategias para su protección. LAST y Biosphere Expedition permanecerán realizando acciones para el correcto funcionamiento del proyecto. En éste informe se hicieron varias recomendaciones para mejor los esfuerzos de conservación. El alto número de cazadores furtivos así como la cacería de las hembras y el saqueo ilegal de huevos siguen siendo un serio problema. El proyecto mantiene una competencia la cual esta resultado exitosa en contra de los saqueadores ilegales con un 75% de nidos salvados en el año. Si las autoridades nacionales apoyaran con la protección y la implementación de las leyes adecuadas, en conjunto a los esfuerzos de conservación, colaboraciones que recientemente han comenzado a suscitarse, en la opinión de los autores, el esfuerzo combinado entre ONGs y autoridades estatales tendrán una mayor posibilidad de reducir el saqueo ilegal de huevos a porcentajes menores al 10%, que cambiaría el enfoque del proyecto de prevenir la extinción de las tortugas marinas a recuperar sus poblaciones.
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EXPEDITION
REPORT
Expedition dates:
8
15 May 201
7
Report published:
April
2018
Protecting leatherback sea turtles through direct
conservation action on the Caribbean coast of Costa Rica
1
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
EXPEDITION REPORT
Gentle giants: Protecting leatherback sea turtles
through direct conservation action
on the Caribbean coast of Costa Rica
Expedition dates:
8
15 May 2017
Report published:
April
2018
Autho
r
s
:
Fabian Carrasco
Latin
American
Sea Turtles
Matthias Hammer
(editor)
Biosphere Expeditions
2
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Abstract
From
27
February until
31 October
2017
,
nesting activities of leatherback turtle
(
Dermochelys coriacea
), green turtle
(
Chelonia mydas
), h
aw
ksbill
turtle
(
Eretmochelys imbricata
) and loggerhead turtle
(
Caretta caretta
)
were recorded
o
n Pacuare beach, on the Caribbean coast of Limon province, Costa Rica.
279
leatherback nests, 72 green turtle nests, 10 hawksbill nest
s
and 1 l
oggerhead
nest were
logge
d
.
200
nests were relocated in
to a custom
-
built
hatchery
where
they were guarded 24/7
, 19 were incubated
ex situ
and
8
were relocated
to a
safe place on
the beach. The eme
rgence success of the nests of l
eatherback
turtle was 58.77% (SD = 24.77, n = 162),
g
reen turtle
71.1% (SD = 23.92, n =
53),
and
hawksbill turtle
71.9% (SD = 23.74, n = 8)
. The single l
oggerhead nest
had
an emergence success of
61.53%. From all the saved nests, a total o
f
12,591 neonates were released
(leatherback
7,349,
green turtle 4,262
,
hawksbill
900
, loggerhead
80
)
.
10 green and 5 hawksbill adult turtles we recorded to have been killed by
poachers; the true number is likely to be higher.
Despite this, the number of
turtles killed is the same or lower than in previous seasons
.
An ave
rage of
75% of turtle nests across four species (
leatherback
5
8%,
green
76%
,
hawksbill
67%
,
loggerhead
100%
)
were saved as a result of the project’s
beach patrol and direct conservation actions.
This percentage of saved nests is
the highest since the proje
ct started in 2012
and should be celebrated as a
major success in sea turtle conservation by LAST, the local community,
Biosphere Expeditions and other partners involved in the project.
Data recorded since 2012 suggest that nesting activity for leatherbac
k and
hawksbill remains stable in Pacuare. However, this should be treated with
caution since the life cycle of these animals is slow.
LAST and Biosphere Expeditions will continue to run this project and make
various recommendations for improvements in t
his report.
T
he high number of
poachers
, as well as the nest and adult poaching rates
,
remain a serious
concern.
This project
continue
s
to fight a successful battle with the poachers
with a high this year of 75%
of
nests saved
.
If
the national authorities
tasked
with nature protection and law enforcement were to join efforts in turtle
conservation
properly
,
and there
I are encouraging signs of this starting to
happen, then i
n
the opinion of the authors, combined action
s
by NGOs and
state authorities will hav
e a high chance of success
of
bringing poaching down
to levels below
10
%
,
which would
turn this project
from extinction prevention
in
to population recovery.
3
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Resumen
Desde el 27 de febrero hasta el 31 de octubre se contabilizaron las actividades de
anidación de la tortuga baula (
Dermochelys coriacea
), tortuga verde (
Chelonia
mydas
), tortuga carey (
Eretmochelys imbricata
) y tortuga cabezona (
Caretta
caretta
) en Playa Pacuare en el Caribe de la Provincia de Limón, Costa Rica.
Se
registraron 279 nidos de tortuga baula, 72 nidos de tortuga verde, 10 nidos de
tortuga carey y un nido de
tortuga cabezona.
200
nidadas fueron trasladas al
vivero donde fueron
incubadas y
protegidas 24/7, 19 fueron incubadas
ex situ
en
hieleras de estereofón
(mientras el vivero estaba en construcción) y ocho
fueron
relocalizadas en zonas seguras de la playa
(también cuando el vivero estaba en
construcción)
.
El porcentaje de emergencia para las nidadas exhumadas de
tortuga baula fue de 58.77% (SD.= 24.77, n = 162), 71.1% (SD = 23.92, n = 53)
para tortuga verde, 71.9% (SD = 23.74, n = 8) para tortuga carey y e
l único nido de
tortuga cabezona presentó 61.53%.
Del total de las nidadas salvadas se liberó un
aproximado de 12,591 neonatos (7, 349 fueron de tortuga baula, 4,262 de tortuga
verde, 900 de tortuga carey y 80 de tortuga cabezona).
Se registró la matanza
de 10 hembras de tortuga verde y 5 hembras de tortuga
carey a manos de los cazadores furtivos pero se calcula que el número real es aún
mayor.
Se estima que el número de tortugas asesinadas es igual o menor que en
las temporadas pasadas.
El 75% de los
nidos de las cuatro especies de tortugas marinas (baula 58%,
tortuga verde 76%, tortuga carey 67%, tortuga cabezona 100%) fueron salvados
como resultado del patrullaje de la playa por parte del proyecto y las acciones de
conservación implementadas.
El por
centaje de nidos salvados es el más alto
obtenido desde inicios del proyecto en el año 2012 y debe ser celebrado como el
mayor logro alcanzado con respecto a la conservación de las tortugas marinas por
parte de LAST, la comunidad local, Biosphere Expeditio
n y demás personas
involucradas en el proyecto.
Los datos obtenidos desde el año 2012 nos demuestran que las actividades de
anidación de la tortuga baula y la tortuga carey permanecen estables en Pacuare.
En todo caso, debido a que el ciclo de vida de
éstos animales es lento, se debe
seguir con precaución con las estrategias para su protección.
LAST y Biosphere Expedition permanecerán realizando acciones para el correcto
funcionamiento del proyecto. En éste informe se hicieron varias recomendaciones
p
ara mejor los esfuerzos de conservación.
El alto número de cazadores furtivos así como la cacería de las hembras y el
saqueo ilegal de huevos siguen siendo un serio problema.
El proyecto mantiene
una competencia la cual esta resultado exitosa en contra d
e los saqueadores
ilegales con un 75% de nidos salvados en el año. Si las autoridades nacionales
apoyaran con la protección y la implementación de las leyes adecuadas, en
conjunto a los esfuerzos de conservación,
colaboraciones
que recientemente han
comenz
ado a suscitarse,
en la opinión de los autores,
el esfuerzo combinado entre
ONGs y autoridades estatales tendrán
una mayor posibilidad de reducir el saqueo
ilegal de huevos a porcentajes menores al 10%,
que cambiaría el enfoque del
proyecto d
e prevenir la extinción de las tortugas marinas a recuperar sus
poblaciones.
4
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
C
o
ntents
Abstrac
t
2
Resumen
3
Contents
4
1. Expedition r
eview
5
1.1. Background
5
1.2. Research
a
rea
6
1.3. Dates
7
1.4. Local conditions & s
upport
7
1.5.
S
cientist
8
1.6. Expedition l
eader
8
1.7. Expedition t
eam
8
1.8
. Partners
9
1.9
.
Acknowledgements
9
1.10
.
Further information & enquiries
9
1
.11
.
Expedition budget
1
0
2.
Annua
l report of the nesting activity of sea turtles in Pacuare
beach, Costa Rica
1
1
2.1. Introduction
and background
1
1
2.2.
Methods
12
2.3. Results
21
2.4
.
Discussion
and conclusions
30
2.5
.
Literature cited
3
6
A
ppendix 1
:
Expedition diary & re
ports
3
8
5
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Please note: Each expedition report is written as a stand
-
alone document that can be read
without having to refer back to previous reports. As such, much of this section, which
remains valid and relevant, is a repetition from previous repor
ts, copied here to provide the
reader with an uninterrupted flow of argument and rationale.
1.
Expedition
r
eview
M. Hammer
Biosphere Expeditions
1.1. Background
Biosphere Expeditions runs wildlife conservation research expeditions to all corners of the
Earth. Our projects are not tours, photographic safaris or excursions, but genuine research
expeditions placing ordinary people with no research experience alongside scientists who
are at the forefront of conservation work. Our expeditions are open to all
and there are no
special skills (scientific or otherwise) required to join. Our expedition team members are
people from all walks of life, of all ages, looking for an adventure with a conscience and a
sense of purpose. More information about Biosphere Expe
ditions and its research
expeditions can be found at
www.biosphere
-
expeditions.org
.
This expedition report deals with an expedition to
Costa Rica
that ran from
8 to 15
May
2017
with the aim of
assisti
ng Latin American Sea Turtles (LAST) in their mission to
protect and research critically endangered leatherback
and other sea
turtles along one of
the world’s most beautiful and biodiverse coastlines.
LAST’s
aims are to reduce poaching
through patrols and
through
relocating nests to a hatchery, and to determine population
parameters of nesting
sea
turtles in order to improve the conservation status of the
various
species
. The emphasis of the May period is on leatherback turtles, which predominantly
come to
nest during this time
. Leatherback turtles are listed as Critically Endangered on
the IUCN
(International Union for the Conservation of Nature)
Red List and the
combination of direct conservation action paired with
the
research
by
this programme will
assis
t
with
the recuperation of this iconic species, ensuring its survival into the future.
Humans have always used the products and sub
-
products of sea turtles as a source of
nutrition and handicrafts
(Groombridge and Luxmoore
1989)
. However, as the human
pop
ulation increases, the demand for these products also rises, creating a black market
and huge pressure on the sea turtles
primarily for the consumption of the meat and eggs
(Chac
ón
2002)
. Since the first studies on nesting sea turtles on the Caribbean sh
ores of
Costa Rica in the 1970s
(Troëng and Rankin
2005)
, it is clear that human demand is at
unsustainable levels, threatening the survival of all seven species of sea turtles
(Chac
ón
2002).
The leatherback sea turtle is the largest of all living turtles
and is the fourth
heaviest
modern reptile behind three crocodilians. It can easily be differentiated from other modern
sea turtles by its lack of a bony shell. Instead, its carapace is covered by skin and oily
flesh. The leatherback turtle is the sea turt
le species with the widest global range,
spanning all oceans as far as the
polar
circles
(Eckert et al. 2012)
. Scientists have tracked
a leatherback turtle that swam from Indonesia to the U.S. in a 20,000 km foraging journey
over a period of 647 days
(Bens
on et al. 2012)
. Leatherbacks follow their jellyfish prey
6
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
throughout the day, resulting in turtles preferring deeper water in the day
time, and
shallower water at night (when the jellyfish rise up in the water column). Leatherback
turtles are known to purs
ue prey deeper than 1,000 m
-
beyond the physiological limits of
all other diving animals except for beaked whales and sperm whales
(Eckert et al. 2012)
.
T
hree major, genetically distinct populations occur in the Atlantic, eastern Pacific, and
western Pac
ific Oceans. Whilst the species as a whole is classed as Vulnerable on the
IUCN’s Red List, the Atlantic subpopulation of this project is considered to be Critically
Endangered. Recent estimates of global nesting populations are that 26,000 to 43,000
femal
es nest annually, which is a dramatic decline from the 115,000 estimated in 1980
(Eckert
et al.
2012)
.
Direct
utili
s
ation
of turtles or eggs for human use (consumption and commercial products)
is one of the major threats
(Chacón 200
2)
and as such
is
the
focus for this project through
direct conservation action such as nest and nesting ground protection and ensuring
hatchling success.
The project involves community members alongside international citizen scientist
s
in its
conservation activities, recruit
ing local people as research and conservation assistants,
and giving them an alternative income to poaching. This is urgently needed in what is a
very isolated and vulnerable community, with very few educational and employment
opportunities.
Through the
construction of an uncontaminated hatchery as a safe incubation zone for
each nest laid on Pacuare beach, the project collects data from eggs and hatchlings and
protects nests from predation and poachers. The leatherback turtle nesting season runs
from Feb
ruary
to
July, with peak nesting activity in April and May. The project is made
possible by the cooperation of the local community
The Environmental Association of
Nuevo Pacuare
and the local coastguards
,
and meets the standards and protocols set
by MI
NAET (Ministerio de Ambiente y Technologia) for handling turtles and their eggs.
1.2. Research area
Costa Rica is a small country in Central America. The country has coastlines on both the
Atlantic and the Pacific and is home to nearly 5% of the planet
s
biodiversity. Despite its
small size, it is considered one of the planet’s top 20 countries in terms of biodiversity.
Indeed,
Costa Rica is known for its progressive (environmental) policies, having disbanded
its army and being the only country in the wor
ld to meet all five criteria established to
measure environmental sustainability. It was ranked fifth in the world and first in the
Americas in the 2012 Environmental Performance Index. It was twice ranked the best
-
performing country in the New Economics F
oundation's (NEF) Happy Planet Index, which
measures environmental sustainability, and
was
identified by the NEF as the greenest
country in the world in 2009. In 2007, the Costa Rican government announced plans for
Costa Rica to become the first carbon
-
neu
tral country by 2021. In 2012, it became the first
country in the Americas to ban recreational hunting.
When
Col
u
mbus
discovered Costa Rica in 1502, the first indigenous people he saw wore
gold bands in their noses and ears
which later led to the name o
f the country
The Rich
Coast
or Costa Rica. In those days, there were four main indigenous tribes, which after
the arrival of the Spanish were decimated by small pox. Today a remarkable 98% of Costa
Ricans are of Spanish descent.
7
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
The project’s study si
te, Pacuare beach, is located in the province of Limon, in the district
of Matina. The project site is only accessible by boat, through the canals of Tortuguero. It
is a very remote and isolated area
rich in wildlife and nature.
Figure 1.2a.
Map a
nd flag of Costa Rica with study site.
An overview of Biosphere Expeditions’ research sites,
assembly points, base camp and office locations
can be
found
at
Google Maps
.
1.3. Dates
The expedition
ran from
8
15
May
201
7
and was
composed of a team of international
research assistants, guides, support personnel and an expedition le
ader (see below for
team details).
1.4. Local conditions & s
upport
Expedition base
The expedition base
was
a remote and rustic research station with cabins for sleeping,
shared bathroom and shower blocks, a kitchen, hatchery and various other utility bu
ildings.
Participants share
d
cabins, with between one
and
three people of the same sex (except
couples) to a cabin.
All meals
were
prepared for the team and special diets
were
catered
for.
Weather
Costa Rica has a tropical climate and the sun shines thro
ughout the year. Day
temperatures during the expedition
were
between 16 and 30° C with slightly lower
temperatures at night and humidity around 80%
(
www.weatherbase.com
)
. There have also
been many non
-
seasonal ra
in events in recent years, so participants
needed to
be
prepared to work in varied weather conditions.
Field communications
M
obile phones worked
intermittently on the beach.
In the field, two
-
way radios and mobile
phones were used for communication bet
ween research teams.
8
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
The expedition leader also
posted an expedition diary on
Biosphere Expeditions’ social
media sites such as
Facebook
,
Google+
and the
Wordpress blog
.
Transport and vehicles
Team members made their own way to the
San Jos
é
assembly point. From there onwards
and back to the assembly point all transport an
d vehicles
were provided
.
Medical
The expedition leader was a trained first aider, and the expedition carried a
comprehensive medical kit.
Further medical support was provided by a clinic
i
n Bataan,
about 40 minutes by boat and 40 minutes by taxi. There
is also a main hospital in Limon,
45 minutes from Bataan by car.
Safety and emergency procedures were in place,
but did
not have to be invoked as there were no accidents or incidents.
1.5.
S
cientist
Fabian Carrasco
was
the head scientist for this expedit
ion and is the on
-
site biologist at
the Pacuare
research site of LAST.
He has dedicated
much of his career
to sea turtle
research and co
nservation, and was previously
a research assistant
at
Pacuare. Fabian
has a Bachelor of Science
degree
in Biology fr
om
the Universidad Autónoma of Morelos,
México.
Fabian
worked with
three species of sea turtle
in México
before joining LAST in
2016.
F
ab
i
a
n i
s a fully qualified first aider
and speaks both English and Spanish
.
1.6. Expedition l
eader
Ida Vincent grew up in
Sweden and lived in Australia for ten years before moving to
Seattle in the USA. Ida studied Marine Biology at the University of Queensland and
Environmental Science at Murdoch University (both in Australia), finishing with BSc and
Masters degrees respecti
vely. Ida has worked as a marine scientist and aquatic ecologist
in Madagascar, Papua New Guinea, the Philippines, Australia and the Pacific Northwest in
the USA. She is also a qualified PADI divemaster, Reef Check trainer, as well as a
climbing leader and
instructor with the North Cascade Mountains as her backyard. Ida also
enjoys photography, painting and writing. She has published both scientific and magazine
articles about alpine climbing,
as well as a murder mystery novel
.
1.7. Expeditio
n t
eam
The ex
pedition team was recruited by Biosphere Expeditions and consisted of a mixture of
ages, nationalities and backgrounds. They were (
in alphabetical order and
with countries
of residence):
Helen Bartholomew (UK), Frank Brett (UK), Eilidh Carrington (Switzer
land), Sandip
Chakraborti (USA), Neil Goodall (UK), Lindsay Hickman (UK), Catherine Maden (UK),
Rosalyn Mayho (UK), Valeria Quesada Phillips (Costa Rica)
*.
*place
ment kindly sponsored via
a
GlobalGiving fundraising campaign
9
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
1.8
.
P
artners
Our partner
on this project is Latin American Sea Turtles (LAST) who represent
WIDECAST (the Wider Caribbean Sea Turtle Network in Costa Rica). LAST has over 28
years of experience in sea turtle management and research and ha
s
attracted various
strategic partners than
ks to their contribution to this field (Whitley Award for Nature, The
Nature Conservancy and WWF)
.
LAST ha
s
initiated projects to monitor reefs, trained
national park rangers in monitoring turtle nesting
,
and educated hundreds of local students
on the impo
rtance of marine and coastal conservation. They also act as environmental
advisors to the government on marine environments, participate in several local, national
and international networks
,
and publish articles to improve
public
knowledge about the
ocean
and its life. In order to reduce threats to sea turtles, and to restore population levels,
LAST has implemented a series of sea turtle management programmes on many of the
Caribbean beaches in Costa Rica
including Pacuare beac
h.
When the Pacuare project
started in 2004, it was just for egg protection and no data were collected. WIDECAST took
over the investigation in 2007 and LAST have become the sole researchers since 2012.
1.9
. Acknowledgements
This study was conducted by Biosphere Expeditions, whi
ch runs wildlife conservation
expeditions all over the globe. Without our expedition team members (listed above) who
provided an expedition contribution and gave up their spare time to work as research
assistants, none of this research would have been poss
ible.
The same is true for all LAST
volunteers, helpers and research assistants, whom we thank too. Thank you also to the
support team and staff (also mentioned above)
, who
were central to making it all work on
the ground. Biosphere Expeditions would also
like to thank the Friends of Biosphere
Expeditions for their sponsorship and/or in
-
kind support
, Thomas Douglas of Hotel Santo
Tomas in San José for his support and advice in Costa Rica, Nicki Wheeler of LAST for
being ever helpful and reliable in setting
things up and keeping them running, Robert
Adeva of La Tortuga Feliz for help and advice in Pacuare. Finally, thank you to the
anonymous reviewers for helpful comments on the various draft versions of this report.
1.10. Further information & e
nquiries
Mo
re background information on Biosphere Expeditions in general and on this expedition
in particular including pictures, diary excerpts and a copy of this report can be found on the
Biosphere Expeditions website
www.biosphere
-
expeditions.org
.
Copies of this and other expedition reports can be accessed via at
www.biosphere
-
expeditions.org/reports
. Enquires should be addressed to Biosphere Expedit
ions via
www.biosphere
-
expeditions.org/offices
.
10
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
1.11
. Expedition b
udget
Each team member paid
a contr
ibution of £1,48
0 per
seven
-
day
slot
towards expedition
costs
. The contribution covered ac
commodation and meals, supervision and induction, all
maps and special non
-
personal equipment,
and
all transport from and to the team
assembly point. It did not cover excess luggage charges, travel insurance, personal
expenses
such as
telephone bills, souv
enirs, etc.,
or
visa and other travel expenses to and
from the assembly point (e.g. international flights).
Details on how these contributions were
spent are given below.
Income
£
Expedition contributions
15,450
Expenditure
Staff
includes loca
l & international salaries, travel and expenses
3,238
Research
includes
equipment
and other research expenses
401
Transport
includes
car hire,
fuel,
taxis and other local transport
650
Base
includes
board and lodging at the research station
1,752
Admi
nistration
includes local sundries, fees and miscellaneous
expenses
50
Team recruitment
Costa Rica
as estimated % of PR costs for Biosphere Expeditions
6,430
Income
Expenditure
2,929
Total percentage spent directly on project
81
%
11
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Please not
e:
This report details the results of an entire nesting season from February to November
2017
. The bulk of the
work
during this period
was conducted by LAST
,
with Biosphere Expeditions assisting during the leatherback nesting
season in May.
Please also n
ote: Each expedition report is written as a stand
-
alone document that can be read without having to refer
back to previous reports. As such, much of this section, which remains valid and relevant, is a repetition from previous
reports, copied here to provi
de the reader with an uninterrupted flow of argument and rationale.
2.
Annual report of the nesting activity of sea turtles in
Pacuare beach, Costa Rica
2.1. Introduction and background
S
ea turtle nesting
o
n Costa Rica
’s
Caribbean coast has been describ
ed since the
19
70s
,
mainly in Tortuguero (Troëng
&
Rankin 2005).
H
umans have been using sea turtle
products and
by
-
products, mainly as a food resource
,
but also
to produce
handicrafts
(Chacón
2002).
More recently,
as a result of
the demographic increase of
Costa Rica
s
population
, the pressure on sea turtle species
has
intensified,
increasing
black market
demand
throughout
the
country, and targeting
sea
turtle eggs and meat.
In an effort to
reduce
the threat
to
sea turtles
and
help to re
-
establish
health
y
sea turtle
population
levels
, a large number of conservation projects
ha
ve
been implemented on the
Caribbean coast of Costa Rica
.
This Pacuare beach p
roject
is one of them
.
LAST (Latin
America
Sea Turtle
s
) in association with WIDECAST
(Wider Caribbean Se
a Turtle
Network)
and the Asociación para el Ambiente de Nuevo Pacuare
established the project
in 2012.
The
p
roject involve
s
the
community in
conservation
activities
such as
guarding
the
hatchery or working as research
assistant
s
on beach patrols. The
community of Pacuare is
located in a remote and rural area of the country
.
C
ommunity members do not have paid
jobs
and many of them are involved in the trafficking and consumption of drugs.
During
sea turtle
season,
vagrant community members come to Pacua
re to poach
eggs and
turtles
,
further
increasing
the pressure
on the
turtle
species.
Conservation activities of this project are highly important to protect and restore the
population of
the four species
that nest
i
n this
area, which are
hawksbill
sea
tu
rtle
(
Eretmochelys imbricata
), leatherback
sea
turtle (
Dermochelys coriacea
), green
sea
turtle
(
Chelonia mydas
) and loggerhead
sea
turtle (
Caretta caretta
). The
hawksbill
is considered
C
ritically
E
ndangered, green turtle and loggerhead turtle are classifie
d as
E
ndangered
on
the IUCN red list
.
The l
eatherback
turtle
was
catalogued
as a Critically Endangered
until
2013
whe
n
the
convention of the
IUCN
Sea Turtles Specialist Group
changed
it status
to
V
ulnerable.
The main objective of
the
Pacu
a
re
p
roject is t
o improve the conservation status of
sea
turtle
species
in the area by
working with the community
and governmental agencies.
Working closely with other institutions and standardising
conservation activities
will help
with the protection of the females duri
ng the nesting
season
and
the
ir
reproductive
success
.
The success rate of the project is
also
strongly
linked
with
the number of
citizen
scientist
volunteers
on the beach
each year as they are a non
-
confrontational counterforce
to
the number of poachers
pr
esent at the same time
. National and international
citizen
scientists
provide help
in
data recording, beach and hatchery maintenance
.
12
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
2.2. Methods
From the month of February until November, daily nightly patrols were
organis
ed to
monitor the 7.1 km
of be
ach administrated by LAST
/
WIDECAST. National and
international
citizen scient
i
sts
were involved in data recording, measurement of nesting
females and hatchlings, as well as nest relocation and maintenance of the hatchery. Such
involvement is a key elemen
t of the project, since none of the nests can be left
in situ
due
to the high poaching activities in the area.
Citizen scientists
are trained upon arrival and
then conduct most activities under the supervision of a trained staff member in order to
reduce b
ias and errors in data recording. Evans
et al. (
2000) and
Birchenough et al.
(2001)
have demonstrated that, given training, volunteers can perform straightforward tasks as
competently as more experienced scientists.
Study site
Pacuare Beach (10°18’48.66
’’N, 83°21’17.25’’W
10°13’25.37’’N, 83°16’47.12’’W) is
located in Costa Rica’s Bataan district within the canton of Matina, in the province of
Puerto Limon (Figure 2.2a). The beach is 7.1 km long and delineated by the Parismina
River mouth in the north a
nd the Pacuare River mouth in the south.
It is a dynamic beach,
susceptible to erosion during high tides. The beach study site is geographically divided into
three se
ctions known for the project as:
Figure 2.2a.
Pacuare beach study site and sectors.
13
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
S
ector A (2.3 km):
This section has parts of the beach close to the vegetation
because so much sand has been washed away
. However, this section sees a lot of
nesting
activity due to its isolation.
Sector B (2.3 km):
This straight, open section of beach is
an important nesting area
but also the area where most poachers
operate
.
Sector C (2.5 km)
:
This sector is the most inhabited and also has the most
driftwood, making nesting activities very challenging for turtles.
In order to facilitate
accurate
loc
ali
s
ation of
nesting activities, the beach is
further
divided
in
to
sectors of 50 metres following a parallel line to the sea. In each site, a wooden marker
carrying
a consecutive number
is
set
.
Numbers
run
from the n
orthern
(Laguna Perla at the
Parismina R
iver mouth
) to the southern limit (Pacuare Riv
er
mouth).
Training
T
raining
of
community
and international
research assistants
took place
during
the
first
week of
March
. R
esearch assistants
participated in
lectures
o
n
biology,
ecology,
threats,
identifica
tion of the species,
conservation strategies and monitoring protocols on nesting
beach
es, as well as
practical training
in
tagging, data recording and relocation of nests.
All
training activities
were coordinated
at
the
LAST
biological station
.
During th
e season,
national and international citizen scientists
were trained by the resident
biologist and
the
research assistants.
On patrols, data
collection
and activities were
supervised by a trained
professional.
Figure 2.2b.
Training session
for expedit
ion citizen scientists
.
14
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Hatchery
A hatchery was built at wooden marker #104, on the vegetation line, in an area subject to
little erosion and without risk of flooding. The hatchery was delimited by a 1.25 m high
metal fence to prevent the intrusion of pr
edators or turtles. During construction, sand was
removed down to a metre depth in the whole area to remove roots, wood and other
elements that could damage the eggs. Later, sand from the low tide line, naturally
sterilised by the sea, was filtered through
a sieve of 0.25 cm mesh and placed in the
selected area. The hatchery was then divided int
o
210
squares of
5
0
x
5
0
cm. Once
constructed, the hatchery was guarded around the clock to prevent poaching, to check on
egg condition at regular intervals
,
and to
prevent ant and other pest infestations.
Figure 2
.2c
.
Hatchery.
Nightly patrols
Staggered patrols of a maximum of
eight
persons per patrol started from 19:00, with the
last patrol leaving the station
at
midnight. Each nightly patrol was guided by a t
rained staff
member and lasted an average of four hours, depending on nesting activity. The distance
usually covered
during a patrol was 10 km
.
Patrols walked in a line parallel to the shoreline and behind the patrol leader in order not
to
miss out on an
y activity. Only red lights and dark clothing were used while recording
biometrics, tagging nesting females, relocation of clutches and release of neonates.
15
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
If a
patrol found a
poacher
who
was already
with a
turtle,
and in line with LAST’s strict non
-
conf
rontation
policy,
the patrol either waited until the oviposition was over
in order
to
record data
,
or kept on pat
rolling
,
depending on the leader’
s decision.
Nest p
rotection
Because of the constant pressure from poaching in Pacuare,
just eight
nests wer
e
relocated
to an alternate safe place on the
beach
. Twenty
nests were incubated
ex situ
.
Both strategies were used because the hatchery was be
ing
buil
t at the time
.
Two hundred
nests were relocated
to
the hatchery
for guarding and hatching. N
est
s were
div
ided into
four categories,
in situ
or natural, relocated at the beach,
ex situ
and relocated
to
the
hatchery
:
The nests
in situ
are
those
left in the
original
place selected by
laying
females at
the time of ovoposition. In Pacuare
,
in situ
nests
were
thos
e
that
were
not
found by
project workers in time
to collect eggs (i.e. when the turtle had already laid her
eggs, covered the nest and left again)
. In that case, patrol members camouflaged
the tracks to confuse poachers and
to prevent them from
locating
eg
gs later on.
N
est
s
relocated
at the beach
are those
that were collected and removed from the
place that the
laying
turtle selected
initially
to a safe
r
place
on
the beach (safe from
erosion or poaching). In Pacuare, relocated nests were
those found at
the
beginning of the season when the hatchery was not
ready to receive eggs yet
.
N
ests incubated
ex situ
are
those
removed from their original place and incubated
in cooler boxes or
S
tyro
foam
boxes
at the LAST biological
station
. This was done at
the beginni
ng of the season whilst the hatchery was being built
.
N
ests
relocated
to
the hatchery
are
those
removed from their original locations
and transferred into the hatchery.
Egg collection
Figure 2
.2
d
.
Egg collection
.
16
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
When
patrols found
a turtle
without
a
poacher present, the patrol leader approached
the
turtle and decided
the correct moment
when the group could approach
without interrupting
the nesting process. When the turtle
had
finished digging the egg chamber, a sterile plastic
bag was
carefully
put
into the hole to collect the eggs the turtle was laying
(Figure 2.2d)
.
M
easurements
of the depth and width of the nest were also made
.
Once the turtle started
to cover the
nest
, the egg bag was pulled out
of the hole
gently and
located
in a safe
place. Bio
metric data was then collected.
Biometrics
After oviposition, the carapace
width and length of
the nesting female
was measured as
shown in Fig
ure
2.
2e
.
Each measurement was
repeated three times and dictated clearly to
the
citizen scientist
in charge of
writing down the data.
Figure 2
.2
e
.
Carapace length (left) and width measurements (right).
Tagging
Before tagging, all turtles were checked for Evidence of Previous Tagging (EPT) and all
information
was
recorded onto the data sheet in accordance w
ith protocol R
-
055
-
2007
(Chacón
et al. 2007
)
as
recommended by
SINAC
(Sistema Nacional de Areas de
Conservación
).
Nesting female without tags, or those who were about to lose tags, were
tagge
d with metal tag Monel #49 (leatherback turtle), as well as PIT tags (passive
integrated transponders). Tags were applied by a trained staff member holding a valid
scientific
tagging licence issued by
MI
NAE
(Ministry of Environment of Costa Rica).
Figure 2.2f.
Placement of the metal
tags in the uropigeal area of a leatherback turtle.
17
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Clutch relocation
Once a clutch of eggs was collected and measuring and tagging of a turtle
was completed
,
the patrol
walked back to the hatchery to relocate the nest.
When transporting the egg bag
it was
handled
steadily
in order
to avoid movements that could
damage the eggs and
cause the abortion of the embryonal
development. Onc
e at the hatchery, one of the 21
0
square
s was chosen, following a rule that each square that takes a nest must be followed
by an empty
square
to avoid
nest
s
damag
ing
each other
(for example
low
/
high
temperature,
excess of / lack of humidity, lack of
oxygen
or infection
)
Visibly normal eggs w
ere relocated and counted first, followed by yolkless or infertile eggs.
A mesh basket was placed on the nest to prevent access by predators and to contain the
neonates at their emergence (Fig
ure
2.
2
c
).
Figure 2
.2g
.
Clutch of eggs next to a leatherback
turtle, ready for relocation.
Neonates
Hatchery shifts lasted
for
six hours maximum at night and two hours during daytime.
N
ests
were checked every
15
minutes
throughout the day and night
to remove crabs, flies and
ants but also to
check
for
any hatchli
ng emergence.
Neonates were released at different parts around the beach
so as
to not create
known
feeding areas for predators. The hatchlings were released at a minimum distance of 10
metr
e
s from the high tide line so they could impri
nt on the beach
.
D
uring nigh
t
time
release,
no
light
was used
to avoid disorientati
ng
the
neonates
. D
uring
daytime,
hatchlings were
kept until 17:00 (when temperature was lowering)
, except on
cloudy or rainy
days
when
daytime releases were allowed if the temperature was low
enough
.
18
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
From every nest, 15 hatchlings were
randomly
chosen
and both length and width of the
carapace were measured with a
caliper.
Neonate
weight
was recorded with
a
50 g
PESOLA scale. L
atex gloves
were used and neonates
were
handle
d
as
gentl
y as possib
le
to
avoid stressing or
disorient
ing
them
.
Figure 2
.2h
.
Measuring a hatchling.
Exhumations
E
xhumations
(Figure 2
.2j)
were
performed
on all hatched nests
to evaluate the percentage
of hatch
l
ing
s
emerged
, the number of hatchlings live/dead remained inside the nest and
analyse the unhatched eggs.
E
ach exhumation was made
within
24 or
48 hours after the
first emergence or 70 days after the nesting date
if no hatchlings had emerged.
From
every
nest, the number of
egg shell
s
,
live neonates
and dead neonates were
recorded
.
Eggs that had not hatched were opened to estimate embryonal development
(Figure. 2.2i).
Figure 2
.2
i
.
Development stages of the embryos in non
-
h
atched eggs (
Chacón et al.
2007)
.
19
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
I) Embryo uses up to 25 % o
f the space inside the egg, II)
up
to
50
%
, III) up to 75%, IV) up to 100%.
The percentage of hatching and emergence
was
cal
culated following the formula:
Where PE = percentage of hatching, PEM = percentage of emergence, C =
empty
shells,
N = total number of eggs and TM = number of dead hatchlings present in the nest or its
surrounding
area
.
Figure 2
.
2j
.
Conducting an exhumation count.
20
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Research permits
On
18
February 2017
the
scientific
permission
to monitor the
four
species of sea turtles
nesting in Pacuare w
as
delivered under resolution SINAC
-
ACLAC
-
PIME
-
R
-
003
-
2017 and
signed by Jorge
Arturo Gonzáles
Villalobos.
2.3
. Results
2.3.1. Leatherback turtle
Nests and false crawl activity
From
26
Febru
ary
to 16
August
2017
a
total of
487
nesting activities were recorded
at
Pacuare Beach
.
279
of
those
activities
were recorded as
successful
ovopositions.
The
remaining
208
were
classified as false crawls,
i.e.
the females emerged from the sea
,
but
the acti
vity did not end in a successful nest.
In comparison
to
the
five
previous seasons
whe
n LAST
has
monitored the beach,
the 2017
season
was an average year (Figure 2.3.1)
,
which is in line with
the inter
-
annual
fluctuations described by several authors (Troëng et al
. 2004, Chacón
-
Chaverri and
Eckert
2007).
806
514
234
599
414
487
514
191
137
388
210
279
0
100
200
300
400
500
600
700
800
900
2012
2013
2014
2015
2016
2017
Total activities
Number of nests
Figure 2.3.1a.
Number of nests and nesting activities of
Dermochelys coriacea
recorded in Pacuare beach since 2012.
21
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Seasonal distribution
April and May
were the months with most nest
ing activity with
81 and 127 nests
respectively
. February and August corresponded to the beginning and
the
end of the
season
with
one nest per month
respectivel
y
.
In
March
and June
there were 22
and 41
successful ovopositions
respectively. At the tail end
of the season in
July there were
six
.
This pattern
is
similar to
the one described
for previous
seasons
(Chacón
-
Chaverri
and
Eckert 2007, Fonseca
et al.
2012, Marion
and
Chacón 2013, Fonseca
and
Chacón 2014,
Marion
2015
).
1
22
81
127
41
6
1
0
20
40
60
80
100
120
140
February
March
April
May
June
July
August
Month
number of nests
Figu
re 2.3.1b.
Seasonal distribution of nesting activity for
Dermochelys coriacea
in Pacuare beach during the year
2017
.
22
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Spatial distribution
During
the
2017 nesting season, nesting activities were
recorded
across all beach sectors.
M
ost
activities
were rec
orded in
sector
s
11
-
20, 51
-
60
and 71
-
80
. Due to the
spatial
distribution
around the entire beach, the protection
of
the nests is a logistic
al
challenge
since it requires personnel present on
seven
kilometr
e
s
of beach
each day and night
.
For
total
coverage
of the beach
a minimum of eight patrols
are
required. T
he average
number
of patrols was six
, which means that there were gaps in coverage (and thus openings for
the poachers).
Figure 2.3.1c.
Spatial distribution
of
nesting activity for
Dermochelys coriacea
in Pacuare beach during the year
2017
.
Green bars correspond to sector A, red bars to sector B and blue bars to sector C
(see page 12)
.
Number of females registered
Nesting turtles are generally classed as either neophytes or remigrants. A neophyte turtle
is one which is in its first reproductive season. This is very
difficult to distinguish without an
internal laparoscopy to determine first
-
time breeding capabilities. For tag and release
program
me
s, the term is often used for fem
ales with no tags or evidence of
previous tags
on flippers and that have not previously be
en recorded nesting at that location. Once
tagged and seen repeatedly nesting within the same season, the turtle is then referred to
as a renesting or interseasonal turtle.
Remigrant turtles are those which have a tagging history of two or more seasons re
corded
in
the same program
me
or at multiple program
me
locations.
23
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
During the 2017 season,
a total of
158 nesting
females were recorded
. 23
were classified
as neophytes
, 124 were seen just on
ce
, 27 were observed nesting twice, four females
were recorded thr
ee times and three females were
registered four times
.
124
27
4
3
0
20
40
60
80
100
120
140
1
2
3
4
Number of females
Number of activities registered
Figure
2.3.1d
.
Number of returning
Dermochelys coriacea
females registered in Pacuare beach during the year
2017
.
Biometrics
The average curve carapace length (CCL) of
the females measured in Pacuare was
150.79
cm (SD
= 7.16
, n
= 150
) and the curve c
arapace width
(CCW)
was 112 cm (SD
=
7.
06
, n
= 149
). These measurements are similar to the ones
recorded
in Gandoca Beach
between
1990 and 2010 (
Chacón
-
Chaverri
and
Eckert
,
2
007, Fonseca
and
Chacón 2010)
and Tortuguero (Harrison
and
Troëng 2003)
.
24
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
0
2
4
6
8
10
12
14
16
130
135
138
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
Curve Carapace Length (CCL)
Frequency
Figure
2.3.1e
.
Distribution of Curve
d
Carapace Length (CCL)
in cm,
found in
Dermochelys coriacea
, Pacuare beach,
2017
.
0
2
4
6
8
10
12
14
16
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
120
121
122
123
124
126
128
129
130
132
133
135
Curve Carapace Width
Frequency
Fi
gure
2.3.1f
.
Distribution of the Curve Carapace Width (CCW)
in cm,
found in
Dermochelys coriacea
, Pacuare beach,
2017
.
Nest c
onservation
During the 2017 season, the
percentage of nests that were
poached
was 4
2
%
(or the
percentage of nests saved
58% (
n
= 162). T
his percentage
of saved nests
is the
highest
since
the project started in 2012
(Figure 2
.3.1g)
.
Of the saved nests,
83
% w
ere
relocated
to
the hatchery,
12
% w
ere
incubated
ex situ
and
5
% w
ere
relocated
to
a safe place
on
the beach. It is
vital
that the maj
ority of saved nests
were relocated in the hatchery because Pacuare is highly frequented by poachers and
25
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
none of the nests can be left
in situ
. The nests incubated
ex situ
were the first nests of the
season, when the hatchery was being built and the number
of volunteers
was
not
high
enough to guard the nests at the hatchery.
44.94
54.06
40.57
37.11
52.83
58.06
0
10
20
30
40
50
60
70
2012
2013
2014
2015
2016
2017
Season
Percentage of saved nests
Figure
2.3.1g
.
Percentage of saved nests for
Dermochelys coriacea
in Pacuare
beach since 2012.
Hatching and emergence success
An estimate
d
7,349
neonates
,
which
emerged from the hatchery, relocated nests and the
styrophoam boxes
,
were
released
at
Pacuare beach during
the
2017 season
.
The emerge
nce
success
of
nests relocated
to
the hatchery
was
6
4
%
. T
his percentage is
the second highest percentage since
the project started in 2012
(Figure 2
.
3
.1h
)
and
higher
than the p
ercentage registered in Gandoca, between
11
and
39%
(Chacón
& Eckert
2007)
and Tortuguero
:
42
%
(Troëng
et al.
2007
)
.
26
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
62.67
60.32
48.86
73.69
50.88
63.92
0
10
20
30
40
50
60
70
80
2012
2013
2014
2015
2016
2017
Year
Percentage of emergence success
Figure
2.3.1h
.
Percentage of emergence success for
Dermochelys coriacea
in Pacuare beach since 2012.
27
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
2.3.2 Green
t
urtle
Nests and false crawl activity
During
the
2017
season,
175
nesting
a
ttempts
were
recorded
for green turtle
,
of which
only 72
resulted
in a
successful
ovoposition. This low number
is
due to
the disturbance
that turtles
experience through
poacher
s
.
79
99
52
32
136
72
0
20
40
60
80
100
120
140
160
2012
2013
2014
2015
2016
2017
Season
Number of recorded nests
Figure
2.3.2a
.
Number of nests of
Chelonia mydas
recorded in Pacuare beach since 2012.
The majority
of
nests were
registered
in
July and
August with
27
and
35
respectively
. I
n
April there were two nests whil
st
in
May and
October there
was
no
nesting activit
y
. (Figure
2.3.2b
).
At
Tortuguero most nests
are
found during September and October (Gonzáles
and
Harrison 2012)
.
2
1
27
35
7
0
5
10
15
20
25
30
35
40
April
June
July
August
September
Month
Number of nests
Figure
2.3.2b
.
Seasonal distribution of nesting activity
of
Chelonia mydas
in Pacuare, Costa Rica
in 2017.
28
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Most of the nesting activity took place in sector 21
-
30 and 61
-
70
(Figure 2.3.2c
). 5
6
% of
the nesting activit
y
was
in the
n
orth part of the beach (after
wooden marker
50).
Figure 2.3.2c.
Spatial distribution of the nesting activity of
Chelonia mydas
in Pacuare, Costa Rica
in 2017
.
Green bars correspond to sector A, red bars to sector B and blue bars to sector C
(see page 12)
.
Number of females registered
In 2017
, 37
nesting
females
were recorded
and
33
did not present any tags
or
evidence of
previous tagging
.
Number
of killed females
Ten green turtle
fem
al
es were
recorded
as
killed by poachers
during the season, which is
the lowest recorded since the project started in 201
2
(Figure 2.3.2d).
44
10
22
16
40
10
0
5
10
15
20
25
30
35
40
45
50
2012
2013
2014
2015
2016
2017
Season
Number of killed turtles
Figure
2.3.2d
.
Number of
Chel
onia mydas
killed in Pacuare, Costa R
ica.
29
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Fate of nests
76% of
nests were protected in
2017. Fifty
-
four nests
were relocated
to
the hatchery and
one was incubated
in a
S
tyro
foam
box.
Hatching and emergence success
The percentage of emergence from the
exhumed
nests was
71
% (SD =
23.92
, n =
53)
with
4,262 neonates
released. T
h
e
percentage
of emergence
is the lowest recorded since
the
project
started in 2012 (Figure 2.3.2e).
81.59
71.55
72.63
72.63
80.83
71.1
64
66
68
70
72
74
76
78
80
82
84
2012
2013
2014
2015
2016
2017
Season
Percentaje of emergence
Figure 2.3.
2e
.
Percentage of nest
emergence for
Chelonia mydas
since 2012 in
Pacuare, Co
sta Rica.
30
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
2.3.3.
Hawksbill turtle
Nests and false crawl activity
21
nesting
activities
were recorded
in 2017
,
of
which
10
were successful
,
All 10 nests were
relocated to the hatchery. T
he highest number of
nesting
activities were in July and August
wi
th seven and six respectively.
Five turtles were recorded to have been killed
(Fig
ure
.
2.3.3a
).
0
5
10
15
20
25
2012
2013
2014
2015
2016
2017
Nesting activities
Relocated nests
Poached nests
Killed turtles
Figure
2.3.3a
.
Nesting activity, number of relocated and extracted nests and killed
Eretmochelys imbricata
since 2012, Pacuare,
Costa Rica.
Hatching and emergence success
The average emergence success
of
exhumed nests was
7
2
% (SD =
23.74%
, n =
8)
rele
asing
an estimate
d
900
hatchlings. The highest
emergence success
percentage was
from
the
nests
relocated in July
(9
5%
)
, while
the
lowest
percentage
was
from a
clutch
relocated
in August (
27%
).
2.3.4.
Loggerhead turtle
One
loggerhead nest
was found in July
and relocated
into
the hatchery. After 55
incubation days, p
ercentage of emergence was 61%, r
eleasing
approx.
80 neonates.
2.
3.5
.
Environmental awareness
Expedition participants
also
took part
in
other
activities
such as weekly beach clean
-
ups.
Mainly plastic waste was collected, then
separated and
later transported to a recycling
cent
r
e
in Bataan.
The very high amount of plast
ic rubbish is
easily observed,
brought by
both the sea and the river. There is no
collection nor recycling coordination
in place locally
and awareness of (plastic) waste avoidance is low.
31
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
2.4. Discussion and conclusions
Leatherback turtle
487 nesting act
ivities of leatherbacks were recorded during the 2017 season.
From
162
clutches moved to the hatchery,
7,349
leatherback
neonates emerged
and were
successfully released
in
to the ocean.
The emergence success was 59% (SD=24.77,
n=162).
The poaching rate for
leather
back was 42%, which means that 5
8% of nests were
saved by the project’s direct conservation action.
T
his percentage
of saved nests
is the
highest
since
the project started in 2012
(Figure 2
.3.1g)
.
The nesting activities registered since 2012
show
that the population of leatherback turtles
remains stable in Pacuare. However, this should be treated
with caution
since the life cycle
of these animals is slow and previous observations have been made of the possible
decline of the fourth biggest rookery
in the world (Troëng
et al.
2004). Pacuare is one of
the most important nesting site
s
in Costa Rica for
l
eatherbacks
,
but still suffers a great
deal of pressure from illegal poaching activities
,
as well as
deaths recorded due to
commercial fish
ing
(Troëng
et al.
2004). LAST and Biosphere Expeditions
therefore
recommend that the program
me
continues its monitoring activities to determine
the
long
-
term
effects of illegal extraction along with the conservation efforts that could prevent the
very real possibilit
y of the
species becoming extinct.
The
phenomenon
that there do not appear to be many remigrant leatherbacks at Pacuare
could be explained by the fact that Pacuare is part of a beach complex where females
nest. The genetic pool of the Western Caribbean (
Dutton
et
al.
2013)
runs from the s
outh
of Nicaragua
to the n
orth of Colombia. So females
can
return to nest in areas where LAST
do not operate.
Green
turtle
175
nesting activities of
green turtle
were recorded during the 2017 season.
From
53
clutches
moved to the hatchery,
4,262
green turtle
neonates emerged
and were
successfully released
in
to the ocean.
The emergence success was
71% (SD=23.92,
n=53)
.
The poaching rate for
green turtle
was 24%, which means that 76% of nests were
saved by the project’s
direct conservation action.
The nesting
distribution pattern
of this species in particular
is
a challenge
for
the project as
it requires people across the beach at all times for good protection of nests.
Also, it
appears that green turtles especially
get
scared
easily
and return to the sea or are hunted
before they finish laying eggs. If we compare
the
2017 season with previous seasons
,
2017 was an average year for laying
.
This
shows the importance
of continuous
monitoring
to determine long
-
term trend
s
and
accurate strategies to conserve and re
-
establish
green
turtle populations.
Ten
green turtles were recorded to have been killed by poachers during the 2017 season.
W
e estimate the
real
number
to be
even higher
,
because poachers
in 2017 started using a
new
poaching strategy
in which they tied a rope to the turtle and let
the animal return
a
rope
length
into the ocean
, only
to retrieve and kill the animal later
during the day, when no
patrols (which work only at night when the turtles come to lay) are around
.
T
he strategy is
applied
so that patrols do not catch poachers in the act of killing
and alert th
e coastguard.
32
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
I
t also allows poachers to capture m
ore turtles as no
time is
spent at night, when the
turtles are around, with killing and butchering, leaving more time for capturing.
This is a
worrying trend. Yet d
espite this, the number of turtles
killed
is the same or lower than
in
previous seasons (Figure
2.3.2d
)
.
This fact
shows
that
direct
conservation
action at
Pacuare
must continue in the face of
poaching pressure and until a time that vagrant poacher presence is much reduced or
eliminated from the beach. This can only be done with the cooperation of
the resident
community and the
help of the coast guard. The latter was very helpful this year,
but
despite this only
one
green turtle
was rescued.
The emergence percentage in 2017 was
the
low
est
percentage recorded since the
beginning of the project in
2012 (
Figure 2.3.2e
).
This was probably b
ecause the nests
were exposed to
varying
temperature
s
for a
longer periods tha
n
usual
due
to
the number
of
poachers on the beach. Because of this p
atrols had to wait until
a
turtle return
ed safely
to the sea, meanin
g eggs were not reburied as quickly as they should have been under
better conditions.
Hawskbill
turtle
21 nesting activities of hawksbill turtle were recorded during the 2017 season.
From
10
clutches moved to the hatchery,
900
hawksbill neonates emerged
and were successfully
released to the ocean.
The emergence success was
7
2
% (SD=23.74, n=8)
. The poaching
rate for
hawksbill
was 33%, which means that 67% of nests were saved by the project’s
direct conservation action.
Five hawksbill turtles were killed b
y poachers.
The nesting activity in 2017 was similar to
the one recorded
in 2014
. Also, this year we had the highest number of killed turtles since
LAST started
the project
in
2012
. Two females were recorded trying to
nest during the day
,
when no patrols
w
ere
out,
in a place 3 km away
from
the project
base. Both where killed.
Loggerhead
turtle
One nesting activity of loggerhead turtle were recorded during the 2017 season.
From
this
one nest
moved to the hatchery,
80
loggerhead neonates emerged
and were su
ccessfully
released to the ocean.
The emergence success was 62%. Since there was only one
loggerhead nest recorded during the season, which was relocated to the hatchery, 100%
of nests were saved by the project’s direct conservation action.
Loggerhead tur
tles
are rarely observed
along
the Caribbean coast of Costa Ri
ca,
especially
at
Pacuare beach
.
Tortuguero National Park and Cahuita are the beaches that
record
the
highest number of loggerhead
nests through
out
the year.
Th
e
recording
of
a
loggerhead
nest
b
y this project during
the
2017 season is a good indicator of the recovery
o
f the population.
It may also be that loggerheads
have
discovered
Pacuare beach as a
relatively
undisturbed place to lay their eggs
,
even
despite
the high numbe
r of poachers
during
the season, which are held in check by the efforts of this project.
33
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Overall efforts
200
clutches
of four different sea turtle species
were relocated
to
the custom
-
built
hatchery,
nineteen
were
incubated
ex situ
, eight were relocated to a safe place
on
t
he
beach
and none were left
in situ
because of the high local poaching rate.
However, overall
75% of all nests of the 2017 season across
the
sea turtle species were saved by the
project’s direct conservation action.
This is the highest number since the p
roject started in 2017 and should be celebrated as a
major success in sea turtle conservation by LAST, the local community, Biosphere
Expeditions and other partners involved in the project.
Additional technology
During th
e
2017
expedition
and in accord
ance with the 2016 recommendations, we trialled
a
handheld forward
-
looking infrared (
FLIR
) device
that help
ed
us to see a leathe
rback
nesting from 30 metr
e
s
away and a poacher walking by.
Discussion
T
he illegal extraction of eggs
continues to be a
challenge for the project
. Since
the start of
the project in
2012
,
data
recorded strongly
indicate
s
tha
t
Pacuare beach is one of the most
important nesting sites
,
for the leatherback turtle
in
particular, but
also for o
ther sea turtles
in Cost
a
Rica
(Marion and Hammer 2017)
.
But e
very season
,
high levels of poaching are
observed
and
whilst
this project is battling successfully to keep poac
hing in check and
save turtles, the overall problem
shou
ld be
dea
lt with some urgency by
the local
authorities, such as the Ministry of Environment and Energy (MINAE)
and the police
(Fuerza Pública), who are tasked with nature protection.
It is self
-
evident that t
h
e eradication of the poaching problem is not
easy, since poaching
provides a very significant income for otherwise very poor and disadvantaged
resident and
transient
communities along Pacuare
beach
.
In addition, most of the individuals involved in
poaching are already outlaws or delinquents with crim
inal records
(as ascertained through
personal communication and observation)
, with a concomitant low threshold towards
further illegal activities.
The high percentage of illegal harvesting is explained by several factors, which are:
The absence of
effec
tive
action
by the
local authorities responsible for the
protection of natural resources, including the National Service of Coastguards
(SNG), Instituto Costarricense de Pesca y Acuacultura (INCOPESCA) and the
Ministry of Environment and Energy (MINAE).
T
he lack of job opportunities in the cantons of Siquirres and Matina, which
encourages or forces a large portion of the population to
turn
to illicit activities such
as drug traffic
king
and the illegal extraction of natural resources.
Not all of the beac
h can be covered all the time by the project due to a combination
of economical restrictions, logistical difficulties and lack of volunteers.
34
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
All of the above
factors
result in
an ongoing
, if successful, struggle of NGOs against
transient and criminal poa
chers, many of whom sustain their alcohol and drug addiction
through the depletion of the population of sea turtles on the Caribbean Coast.
As long as
NGOs are by and large left to continue this struggle by themselves
, poaching will remain a
problem and ne
sts will continue to be poached
. Despite this, and given enough future input
from international volunteers and citizen scientists, many nests will continue to be saved
and many hatchlings will be helped into the ocean, thereby preventing the local extincti
on
of sea turtle populations.
If, however, the national authorities tasked with nature protection and law enforcement
were to join efforts in turtle conservation, then this could be turned from extinction
prevention
in
to population recovery.
In the opini
on of the authors, combined action will
have a high chance of success in bringing poaching down to levels below
10
%.
In 2017 there were encouraging signs of this
beginning to happen
. The local coast guard
started to run s
poradic patrol
s of the beach. F
ive
poachers were arrested and taken to trial
as a result,
which did
seem to
have some effect on
poachers
, who
appeared
to spend
fewer
hours on the beach at night.
We use cautious wording here, because we do not
have any hard data to support this supposition.
We did, however, come across more
turtles in the process of laying tha
n
usual, with no poachers present, which suggests that
fewer
poachers
were active.
Even a slight increase in authority involvement is to be welcome
d
. Ultimately, however,
authorities s
hould be proactive in the
removal of transient, crimin
al poachers from the
community. This
can only be achieved
with the
cooperation
of the community
,
which could
lead, in an ideal world,
to the establishment of safe, nature
-
based tourism in the area with
significant econom
ic benefits for the community. This
social and economic development of
the community of Pacuare is a crucial parameter to allow LAST to meet its obje
c
tives and
to
protect the population of sea turtles.
LAST also
recommend
s
the creation
of
ecotourism activities, such as
English classes for
locals and
the
development of alliances with partners to promote sustainable exploitation
of the natural resources of Pacuare.
A
police station
should be set up
to regulate, monitor
and control
such act
ivities and
to
support both the locals and the tourists in case of
emergency.
La Tortuga Feliz Foundation is a Dutch foundation established in Pacuare
in
2004
which
assist
s
LAST in its mission by recruiting intern
ational volunteers; both organis
ations
d
onate a percentage of the income provided by the international volunteers to the
Asociación para el Ambiente de Nuevo Pacuare
, which
is in charge of employing the local
research assistants. A high number of volunteers allows the recruitment of additional l
ocal
guides but the month of April, which is the beginning of the peak nesting activity, is
generally less frequented by volunteers
. Therefore there
were
nights when
the beach
was
understaffed and the
opportunities for poachers were drastically increased.
Therefore,
LAST must continue to
work with
research partners
, such as Biosphere Expeditions,
so
that more
volunteers
can be
found
to patrol the beach
each night
. This will not only help
LAST to reach its objectives
,
but also bring a stable alternative live
lihood to the community
of Pacuare.
35
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
It is also crucial to raise environmental awareness
amongst
the
local
population of
Limon
province so that the consumption of
turtle
meat and eggs
is reduced
. Without consumers,
there would not be any market, and poach
ing
would cease
.
T
he involvement of the municipality of Siquirres
in
the construction of properties in public
area
s
is another important
point to be considered
.
Most of
the poachers live in slums or
ranchos built illegally and without proper handling of
h
uman waste
. If the municipality could
remove these itinerant persons, they would be contributing to the reduction of the illegal
extraction of eggs and killing of
turtles
.
The accumulation of rubbish on the beach
could be prevented by setting up an eff
ective
collection system in the municipalities surrounding the area.
T
here is
in fact
no
rubbish
collectio
n
or recycling coordination in place
at all
for the communities
adjacent to the
Pacuare River.
Recommendations for the
2018
season
LAST and Biosph
ere Expeditions recommend several measures to ensure population
protection and recovery of all
four
turtle
species
present in Pacuare:
T
he use of
Styrofoam boxes as
a replacement
artificial hatchery
at times
when
erosion patterns prevent
the building of a
beach hatchery and when the numbers of
volunteers
are not enough to conduct
patrol
s
as well as
hatchery
guarding
activities
at the same time
.
The use of l
ong
-
range radios
is
crucial to coordinate the relocation of clutches and
to ensure a more efficient
coverage of the beach.
The
use of
a
handheld forward
-
looking infrared (FLIR) device should be tried with
all
species. If the device is able to recogni
s
e turtles in
side
the vegetation (where
green and hawksbill turtles prefer to nest)
or in the waves (when
a poacher is
attempting to capture
a turtle)
,
the
n
the
number of saved turtles
and nests
c
ould
increase considerably.
Continu
ed
nurturing of
the
existing
relationship with the Coastguards
is critical, so
that the joint
efforts of law reinforcement author
ities
and
NGOs
can
continue to
combat and eventually eradicate
illegal
turtle poaching and killing
activities in
Pacuare.
The d
evelopment of
alternative livelihood opportunities for the local community
is
vital
as a measure to reduce poaching activities a
nd support the community in
developing itself to attract eco
-
tourism and voluntourism.
36
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
2.5.
Literature
cited
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. Dutton (2011) Large
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scale movements and high
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use areas of western Pacific leatherback turtles, Dermochelys coriacea.
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Chacón, D.
(2002)
Diagnóstico sobre el comerciode las tortugas marinasy sus derivados en el
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Centroamérica (RCA). San José, Costa Rica. 1
44 pages.
Chacón, D., J. Sánchez, J. J. Calvo
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J. Ash (2007)
Manual para el manejo y la conservación de
las tortugas marinas en Costa Rica; con
énfasis en la operación de proyectos en playa y viveros.
Sistema Nacional de Áreas de Conservación, Ministerio d
e Ambiente y Energía. 103 pages.
Chacón
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Chaverri, D.
,
and
K. L. Eckert (
2007)
Leatherback Sea Turtle Nesting to Gandoca Beach
in Caribbean Cost
a Rica: Management Recommendations from Fifteen Years of Conservation.
Chelonian Conservation Biology 6: 101
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110.
Dutton, P.H., Roden, S.E., Stewart, K.R., LaCasella, E., Tiwari, M., Formia, A., Thomé, J.C.,
Livingstone, S.R., Eckert, S., Chacon
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Chaverri,
D. and Rivalan, P.
(
2013
)
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) in the Atlantic revealed using mtDNA and
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636.
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, and P.C.H. Pritchard (2012) Synopsis of the
biological data on the leatherback sea turtle (Dermochelys coriacea). U.S. Department of Interior,
Fish and Wildlife Service, Biological Technical Publication BTP
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R4015
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2012, Washington, D.C.
Fonseca, L. G. an
d D. Chacón. (2010).
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Caribe Sur, Costa Rica. Informe temporada 20
10 WIDECAST. 24 pages.
Fonseca, L. G., H. Alguera, B. Vanegas
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D. Chacón
(
2012)
Reporte final de la anidación de
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Chacón
(
2014
)
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. Informe Técnico. STC. 56 pages.
Groombridge, B. and R. Luxmoore (1989).The green turtle andhawksbill (Reptilia: Cheloniidae):
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Pacuare, Costa Rica 2013.
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. 25 pages.
Marion, M.
(2015)
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. 28 papges.
37
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Marion, M. and Hammer, M. (2017)
Gentle giants:
Protecting leatherback sea turtles through direct
conservation action on the Caribbean coast of Costa Rica
. Expedition report for e
xpedition dates: 2
19 May 2016
. Available via
www.biosphere
-
expeditions.org/reports
.
Troëng, S., D. Chacón
and
B. Dick (2004)
Possible decline in leatherbackturtle
Dermochelys
coriacea
nesting
along the coast o
f Caribbean Central America.Oryx 38: 395
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403.
Troëng, S.
and
E. Rankin (2005)
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term conservation efforts contribute to positive green turtle
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ans, A. de Haro, and E. Vargas (2007)
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122.
38
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum
Officially acc
redited member of the International Union for the Conservation of Nature
Appendix 1
:
Expedition diary & reports
A multimedia expedition diary is available on
https://biosphereexpeditions.wordpress.com/cat
egory/expedition
-
blogs/costa
-
rica
-
2017/
All expedition reports, including this and previous expedition reports,
are available on
www.biosphere
-
expeditions.org/reports
.
ResearchGate has not been able to resolve any citations for this publication.
Research
Full-text available
Monitoring of sea turtle nesting activities took place from 24 February-15 November 2016 in Pacuare Beach (Caribbean coast of Costa Rica). Monitoring was conducted by Latin American Sea Turtles (LAST) and assisted by Biosphere Expeditions citizen science volunteers from 2-19 May 2016. 414 nesting activities of leatherback turtle (Dermochelys coriacea), 525 of green turtle (Chelonia mydas) and 22 of hawksbill turtle (Eretmochelys imbricata) were recorded. 220 clutches were relocated to the custom-built hatchery, three were left in situ. None were relocated on the beach, because of the very high local poaching rate. From clutches moved to the hatchery, 12,755 neonates emerged (4,147 leatherback, 8,266 green, 342 hawksbill turtle) and were successfully released to the ocean. The percentages of emergence recorded were 51% (SD=30.31, n=112) for leatherback, 81% (SD = 21.33, n = 95) for green and 66% (SD = 37.82, n = 4) for hawksbill turtle. The average nest poaching rate recorded for each species was 40% for leatherback, 23% for green and 43% for hawksbill turtle. In addition, 40 green sea turtles and two hawksbill turtles were recorded to have been killed by poachers. The data recorded in 2016 (and since 2012) indicate clearly that Pacuare beach is one of the most important nesting sites for the leatherback turtle in Cost Rica. Nevertheless, very high levels of poaching continue, predominantly perpetrated by transient and criminal poachers who frequent the beach during the nesting season. There is currently little support and attention from government authorities tasked with nature conservation and law enforcement, which means that NGOs such as LAST and Biosphere Expeditions, with the critical help from national and international volunteers and citizens scientists, by and large struggle against poachers unaided. Even with the very positive nest and turtle protection, as well as neonate hatching rates reported here, this means that conservation activities by NGOs alone are unlikely to go beyond preventing the extinction of local turtle populations. Whilst this is in itself a vital contribution to sea turtle survival, help by government authorities, which are after all tasked with nature protection and law enforcement, could transform efforts from extinction prevention to population recovery with concomitant benefits for the local population through sustainable, turtle-based ecotourism in a safe area free from criminal poachers. LAST and Biosphere Expeditions therefore strongly recommend that the project continues in order to prevent local turtle extinction, to gather sufficient scientific information that will allow the creation of conservation tools such as protected areas, and to build partnerships with government and other agencies that will lead to a recovery of the populations of sea turtles on the Caribbean coast of Costa Rica. 3 © Biosphere Expeditions, an international not-for-profit conservation organisation registered in England, Germany, France, Australia and the USA Officially accredited member of the United Nations Environment Programme's Governing Council & Global Ministerial Environment Forum Officially accredited member of the International Union for the Conservation of Nature Resumen El monitoreo de las actividades de anidación en Playa Pacuare (Costa Caribe de Costa Rica) se realizó entre el 24 de febrero y el 24 de noviembre 2016. El monitoreo fue coordinado por Latin American Sea Turtles (LAST) y apoyado por voluntarios ciudadanos del 2-19 mayo 2016. 414 actividades de tortuga baula (Dermochelys coriacea), 525 de tortuga verde (Chelonia mydas) y 22 de tortuga carey (Eretmochelys imbricata) fueron observadas. 220 nidadas fueron relocalizadas en el vivero de tortugas marinas, tres se dejaron in situ y ninguna nidada fue reubicada en la playa por el problema de saqueadores furtivos. De las nidadas relocalizadas en el vivero, 12,755 neonatos emergieron (4,147 tortugas baula, 8,266 tortuga verde y 342 tortuga carey) y fueron liberadas al mar. Los porcentajes de emergencia registrados fueron 51% (SD=30.31, n=112) para la tortuga baula, 81% (SD = 21.33, n = 95) para la tortuga verde y 66% (SD = 37.82, n = 4) para la tortuga carey. El promedio de saqueo ilegal registrado fue de 40% para la tortuga baula, 23% para la tortuga verde y 43% para la tortuga carey. Además, 40 tortugas verde y dos tortugas carey fueron matadas por cazadores furtivos. Los datos registrados en 2016 (y desde 2012) demuestran que Playa Pacuare es uno de los sitios de anidación más importante para la tortuga baula en Costa Rica. Sin embargo, la tasa de saqueo ilegal sigue siendo muy alta, involucrando principalmente saqueadores transitorios quien se apoderan de la zona durante la temporada de anidación. Presentemente, se observa poco apoyo y atención de parte de las autoridades gubernamentales responsables del reforzó de las leyes ambientales; eso significa que ONGs tal como LAST y Biosphere Expeditions, con la ayuda critica de voluntarios nacionales e internacionales y científicos ciudadanos, se enfrentan a una lucha desbalanceada con los saqueadores ilegales. A pesar de la protección positiva de las nidadas y de las hembras, además de la tasa alta de emergencia de los neonatos reportados aquí, es poco probable que las ONGs logran más allá que la prevención de la extinción de las poblaciones locales de tortugas marinas. Aunque es una contribución vital a la supervivencia de las especies de tortugas marinas, la ayuda de las autoridades gubernamentales podría transformar el esfuerzo contra la extinción de las poblaciones a un esfuerzo de recuperación de las poblaciones junto con beneficios hasta la población local a través de un eco-turismo responsable basado en las tortugas marinas, en una zona libre de saqueadores furtivos.
Article
Full-text available
This study presents a comprehensive genetic analysis of stock structure for leatherback turtles (Dermochelys coriacea), combining 17 microsatellite loci and 763 bp of the mtDNA control region. Recently discovered eastern Atlantic nesting populations of this critically endangered species were absent in a previous survey that found little ocean-wide mtDNA variation. We added rookeries in West Africa and Brazil and generated longer sequences for previously analyzed samples. A total of 1,417 individuals were sampled from nine nesting sites in the Atlantic and SW Indian Ocean. We detected additional mtDNA variation with the longer sequences, identifying ten polymorphic sites that resolved a total of ten haplotypes, including three new variants of haplotypes previously described by shorter sequences. Population differentiation was substantial between all but two adjacent rookery pairs, and F ST values ranged from 0.034 to 0.676 and 0.004 to 0.205 for mtDNA and microsatellite data respectively, suggesting that male-mediated gene flow is not as widespread as previously assumed. We detected weak (F ST = 0.008 and 0.006) but significant differentiation with microsatellites between the two population pairs that were indistinguishable with mtDNA data. POWSIM analysis showed that our mtDNA marker had very low statistical power to detect weak structure (F ST < 0.005), while our microsatellite marker array had high power. We conclude that the weak differentiation detected with microsatellites reflects a fine scale level of demographic independence that warrants recognition, and that all nine of the nesting colonies should be considered as demographically independent populations for conservation. Our findings illustrate the importance of evaluating the power of specific genetic markers to detect structure in order to correctly identify the appropriate population units to conserve.
Article
Full-text available
Leatherback turtle (Dermochelys coriacea) nesting activity was monitored, individual movements via flipper tag recoveries and satellite telemetry were determined, and illegal egg collection was quantified at Tortuguero, Costa Rica from 1995 to 2006. Annual nest deposition was estimated at 199–1,623 nests per year; a Bayesian regression model suggests that leatherback nesting decreased by 67.8% between 1995 and 2006. Tag recaptures from fisheries bycatch and strandings have been reported from Cuba, Nicaragua, and the United States. Two leatherbacks were followed with satellite telemetry; 1 swam to Cuba and 1 moved into the northwest Atlantic Ocean. Minimum rates for illegal egg collection from 2000 to 2005 were estimated at 13.0%–21.5%.
Article
Full-text available
Leatherback turtle Dermochelys coriacea nesting has declined on Pacific beaches and as a result the species is considered Critically Endangered. Atlantic populations are, however, also important for the species' survival and therefore we undertook a study to quantify the size and nesting trend of the Caribbean Costa Rica and Panama leatherback turtle rookery. Tag returns show that post-nesting females from the rookery disperse throughout the Caribbean, Gulf of Mexico and North Atlantic. Aerial and track survey results were used to estimate 5,759–12,893 nests per year between San Juan river and Chiriquí beach, making this the fourth largest rookery worldwide. Monitoring results from three beaches (Tortuguero, Pacuare and Gandoca) were used to examine any temporal trend in nesting using nonparametric regression. Nesting appeared to decline slightly from 1995 to 2003 but the trend could be an artefact of interannual variation in nest numbers. Explanations for the difference in nesting trends over the past 15 years for Pacific (rapid decline) and Caribbean (slight decline or stable) rookeries include: (1) hatching success on Caribbean beaches has been higher due to dispersed nesting, (2) fisheries bycatch has been greater in the Pacific, and (3) less overlap between fishing areas and leatherback turtle habitats in the Atlantic. Quantification of human-caused mortality of all life stages and knowledge of the marine habitats used by Atlantic leatherback turtles are required to facilitate the development and implementation of effective strategies to reduce threats and avoid a repeat of the decline that has occurred in the Pacific population.
Article
Full-text available
Worldwide, green turtle Chelonia mydas populations have declined and the species is classified as globally endangered. Tortuguero, Costa Rica, hosts the largest remaining green turtle rookery in the Atlantic basin. Tortuguero green turtles have been hunted since pre-Columbian times. Monitoring and conservation of the green turtle population began in 1955. The long-term efforts provide an excellent opportunity to evaluate the success of sea turtle conservation action and policies. Nest counts conducted 1971–2003 were analyzed to: (1) determine the nesting trend, (2) estimate rookery size and (3) identify events and policy decisions influencing the trend. A nonparametric regression model indicates a 417% increase in nesting over the study period. Rookery size was defined as the mean number of nests 1999–2003 and estimated at 104,411 nests year−1, corresponding to 17,402–37,290 nesting females year−1. A comparison with 34 index populations verifies Tortuguero as one of the two largest green turtle rookeries worldwide. Events and policy decisions in Costa Rica, Nicaragua, and Panama that comprise the main nesting, feeding and mating grounds for the Tortuguero population are likely to have had the greatest influence on green turtle survivorship. Conservation efforts and policies catalyzing increased hatchling production and decreased adult and juvenile mortality since 1963 have contributed to the positive nesting trend. The trend demonstrates that long-term conservation efforts can reverse nesting declines and offers hope that adequate management can result in recuperation of endangered sea turtle species.
Article
Field research was conducted, from 1990 to 2004, at Gandoca Beach (9°59.972′N, 82°60.530′W), located within the Gandoca-Manzanillo National Wildlife Refuge at the southernmost extreme of the Caribbean coast of Costa Rica. Nightly patrols of the 8.85-km nesting beach were undertaken annually from the second week of February through the last week of July, and pertinent information regarding the nesting process was recorded. An estimated 90% of all nesting females were documented and uniquely tagged; these 2751 females deposited 8766 nests (believed to be a complete count). Averaged over the 15-year study period, 12.5% of all nests were left unaltered in situ; 12.9% were left in situ, with tracks camouflaged by beach patrollers; 33.9% were relocated to lower risk zones on the beach; and 25.4% were relocated to beach hatcheries. Poaching, which had once claimed nearly 100% of all eggs laid, averaged 15.5% annually during the study period, demonstrating a clearly declining trend, attributable to the presence of beach patrollers, policies associated with the wildlife refuge, and changing attitudes within proximal communities. A comparison of tag registries indicates an interchange of gravid females among nesting beaches both within Costa Rica and internationally with Panama and Colombia. The interchange reinforces the importance of joint efforts to address primary threats, including beach erosion, egg poaching, direct harvest of adults for meat (especially in Panama), and coastal development. The population is statistically stable but shows a steadily declining trend in the number of nests laid since 2000.
Diagnóstico sobre el comercio de las tortugas marinas y sus derivados en el istmo centroamericano. Red Regional para la Conservación de las Tortugas Marinas en Centroamérica (RCA)
  • D Chacón
Chacón, D. (2002) Diagnóstico sobre el comercio de las tortugas marinas y sus derivados en el istmo centroamericano. Red Regional para la Conservación de las Tortugas Marinas en Centroamérica (RCA). San José, Costa Rica. 144 pages.
Manual para el manejo y la conservación de las tortugas marinas en Costa Rica
  • D Chacón
  • J Sánchez
  • J J Calvo
  • J Ash
Chacón, D., J. Sánchez, J. J. Calvo and J. Ash (2007) Manual para el manejo y la conservación de las tortugas marinas en Costa Rica; con énfasis en la operación de proyectos en playa y viveros.
Synopsis of the biological data on the leatherback sea turtle (Dermochelys coriacea). U.S. Department of Interior, Fish and Wildlife Service
  • K L Eckert
  • B P Wallace
  • J G Frazier
  • S A Eckert
  • P C H Pritchard
Eckert, K.L., B.P. Wallace, J.G. Frazier, S.A. Eckert, and P.C.H. Pritchard (2012) Synopsis of the biological data on the leatherback sea turtle (Dermochelys coriacea). U.S. Department of Interior, Fish and Wildlife Service, Biological Technical Publication BTP-R4015-2012, Washington, D.C.