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Expedition report: Gentle giants: Protecting leatherback sea turtles through direct conservation action on the Caribbean coast of Costa Rica (May 2018)

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Abstract and Figures

From 24 February until 31 October 2018 nesting activities of leatherback turtles (Dermochelys coriacea), green turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) were recorded on Pacuare beach, Costa Rica. A total of 191 sea turtle nests were protected (leatherback = 156, green = 29, hawksbill = 6). 173 nests were relocated to the hatchery and 18 nests were reburied in a safe place at the beach. The emergence percentage of the exhumed nests of leatherback turtle was 67% (SD = 21.52, n = 155), 74% (SD = 20.23, n = 24) for green turtle and 88% (SD = 20.78, n = 6) for hawksbill turtle. A total of 10,960 neonates were released from all the protected nests (leatherback = 8,112, green = 2,038, hawksbill = 810). Ten green and five hawksbill turtles were killed by poachers, which is the same number of turtles killed as during the 2017 season, and evidence that poaching continues, but is not increasing. 65% of the total nests laid by the three species were saved as a result of the direct conservation actions taken by LAST, Biosphere Expeditions, the community and all the other partners involved in the project. This percentage of saved nests is the highest since the project started in 2012 and a credit to all involved. The population of leatherback turtle remains stable, which is encouraging, albeit at a relatively low level due to lack of remigrant leatherbacks. Elsewhere, however, steep declines of up to 60% have been noted. 65% of leatherback nests were saved. 69% of green turtle nests were saved and 46% of hawksbill turtle. Challenges remain, especially those related to a lack of human resources available to patrol the beach to prevent poaching and the almost complete absence and lack of support from law enforcement, especially the coast guard. On the rare occasion that the coast guard is present, arrests are made, which anecdotal evidence suggests has a positive impact on reducing poaching activity at the beach overall. Given this, continued direct conservation actions such as nightly patrols and hatchery construction and guarding by the project, supported by citizen scientists and the community, are critical for sea turtle survival at Pacuare and elsewhere. LAST and Biosphere Expeditions will continue the project in Pacuare beach to save nests and combat poaching, and to generate more scientific information in order to create management and conservation strategies to aid sea turtle population recovery. We encourage law enforcement to assist. If the police and coast guard were to help with beach patrolling, as well as the arrest and prosecution of poachers, the number of saved nests would increase considerably. 3 © Biosphere Expeditions, an international not-for-profit conservation organisation 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 Desde el 24 de febrero al 31 de octubre 2018 se registraron las actividades de anidación de tortuga baula (Dermochelys coriacea), tortuga verde (Chelonia mydas) y tortuga carey (Eretmochelys imbricata) en Playa Pacuare, Costa Rica. Durante la temporada se protegieron un total de 191 nidos de tortugas marinas de los cuales 156 correspondieron a tortuga baula, 29 a tortuga verde y seis de tortuga carey. 173 nidos fueron relocalizados en el vivero y 18 nidos fueron reubicados en sitios seguros en la playa. El porcentaje de emergencia para las nidadas exhumadas de tortuga baula fue de 67% (SD = 21.52, n = 155), 74% (SD = 20.23, n = 24) para tortuga verde y 88% (SD = 20.78, n = 6) para tortuga carey. Del todas las nidadas protegidas se liberaron un total de 10,960 neonatos de los cuales 8,112 fueron de tortuga baula, 2,038 de tortuga verde y 810 de tortuga carey. Un total de 10 hembras de tortuga verde y cinco de tortuga carey fueron asesinadas durante la temporada; misma cantidad de tortugas asesinadas que la temporada 2017. Evidencia de que la matanza de tortugas continúa constante pero no está aumentando. El 65% del total de nidos depositados por las tres especies fueron salvados como resultado de las acciones de conservación tomadas por LAST, la comunidad local y las personas involucradas en el proyecto. Éste porcentaje de nidadas protegidas es el más alto registrado desde el inicio del proyecto en 2012. La población de tortuga baula permanece estable, lo cual es alentador, aunque a un nivel relativamente bajo debido a la falta de hembras remigrantes. Sin embargo, en otros lugares, se han observado fuertes caídas de hasta el 60%. El 65% de nidos de tortuga baula fueron salvados. El 69% de nidos de tortuga verde y el 46% de tortuga carey fueron salvados. Los desafíos permanecen, especialmente los relacionados a la falta de personal disponible para patrullar la playa para prevenir la extracción ilegal de nidadas y la cacería de hembras anidantes, y la falta de apoyo por parte de las instituciones gubernamentales, como el servicio nacional de guardacosta. En las raras ocasiones que los guardacostas estuvieron presentes lograron hacer algunos arrestos, lo que que tuvo un impacto positivo reduciendo considerablemente las actividades ilegales de extracción de nidadas y cacería de tortugas. Bajo este escenario, la continuidad de las actividades directas de conservación, como patrullaje nocturno, construcción y cuidado de vivero por parte del proyecto apoyado por los ciudadanos científicos, la comunidad local son críticas para la supervivencia de las tortugas marinas en Pacuare y en otros lugares.
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EXPEDITION
REPORT
Expedition dates:
7
14 May 2018
Report published:
April
2019
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 accredited member o
f 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:
7
14 May 2018
Report published:
April
2019
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 accredited member o
f the International Union for the Conservation of Nature
Abstract
From 24 February
unti
l
31
October
2018
nesting activities o
f leatherback turtles
(
Dermochelys coriacea
), green turtles (
Chelonia mydas
) and
hawksbil
l turtles
(
Eretmochelys imbricata
)
were recorded
on Pacuare beach, Costa Rica
. A total
of 191 sea turtle nests were protected
(
leatherback
= 156,
green
= 29, hawksbill
= 6).
173 nests were relocated
to
the hatchery and 18 nests were
re
buried in a
safe plac
e at the beach. The emergence percentage of the exhumed nest
s of
leatherback turtle was 67% (SD = 21.52, n = 155), 74
% (SD = 20.23, n
= 24) for
green turtle and 88
% (SD = 20.78, n = 6) for hawksbill turtle.
A total of 10,960 neonates were release
d from a
ll the protected nests
(leatherback = 8,112, green =
2,038
,
hawksbill
= 810)
.
Ten green and five
hawksbill turtles were killed by poach
ers, which is the same number of turtles
killed as
during the 2017
season, and evidence that poaching
continues, but is
n
ot increasing.
65
% of the t
otal nests laid by the three species were saved as a result of the
direct
conservation actions taken by LAST
,
Biosphere Expeditions,
the
community and all the
other
partn
ers
involved in the project.
This percentage of
saved nest
s is the highest since the project started in 2012
and a credit to all
involved
.
T
he population of leatherback turtle remains stable,
which is encouraging, albeit
at a relatively low level due to lack of remigrant leatherbacks
. Elsewhere,
however, steep d
eclines of up to 60% have been noted.
65% of leatherback
nests were saved.
69% of green turtle nests were saved and 46% of hawksbill turtle.
Challenges
remain, especially those related to a lack of human resources available to patrol
the beach to prevent
poaching and the almost complete absence and lack of
support from law enforcement, especially the coast guard. On the rare occasion
that the coast guard is present, arrests are made, which anecdotal evidence
suggests has a positive impact on reducing poach
ing activity at the beach
overall. Given this, continued direct conservation actions such as nightly patrols
and hatchery construction and guarding by the project, supported by citizen
scientists and the community, are critical for sea turtle survival at P
acuare and
elsewhere.
LAST
and Biosphere Expeditions
will continue
the project in Pacuare beach
to
save nests and combat poaching, and to
generate more scientific information in
order to create management and conservation strategies
to aid sea turtle
popu
lation
recovery
.
We encourage law enforcement to assist.
If
the police and
coast guard
were to help with beach patrolling, as well as the arrest and
prosecution of poachers,
the number of
saved
nests would increase
considerably.
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 accredited member o
f the International Union for the Conservation of Nature
Resumen
Desde el 24 de
febrero al 31 de octubre 2018 se registraron las actividades de
anidación de tortuga baula (Dermochelys coriacea), tortuga verde (Chelonia
mydas) y tortuga carey (Eretmochelys imbricata) en Playa Pacuare, Costa Rica.
Durante la temporada se protegieron un
total de 191 nidos de tortugas marinas de
los cuales 156 correspondieron a tortuga baula, 29 a tortuga verde y seis de
tortuga carey. 173 nidos fueron relocalizados en el vivero y 18 nidos fueron
reubicados en sitios seguros en la playa. El porcentaje de
emergencia para las
nidadas exhumadas de tortuga baula fue de 67% (SD = 21.52, n = 155), 74% (SD
= 20.23, n = 24) para tortuga verde y 88% (SD = 20.78, n = 6) para tortuga carey.
Del todas las nidadas protegidas se liberaron un total de 10,960 neonatos d
e los
cuales 8,112 fueron de tortuga baula, 2,038 de tortuga verde y 810 de tortuga
carey. Un total de 10 hembras de tortuga verde y cinco de tortuga carey fueron
asesinadas durante la temporada; misma cantidad de tortugas asesinadas que la
temporada 2017.
Evidencia de que la matanza de tortugas continúa constante pero
no está aumentando.
El 65% del total de nidos depositados por las tres especies fueron salvados como
resultado de las acciones de conservación tomadas por LAST, la comunidad local
y las pers
onas involucradas en el proyecto. Éste porcentaje de nidadas protegidas
es el más alto registrado desde el inicio del proyecto en 2012.
La población de tortuga baula permanece estable, lo cual es alentador, aunque a
un nivel relativamente bajo debido a l
a falta de hembras remigrantes. Sin embargo,
en otros lugares, se han observado fuertes caídas de hasta el 60%. El 65% de
nidos de tortuga baula fueron salvados.
El 69% de nidos de tortuga verde y el 46% de tortuga carey fueron salvados. Los
desafíos perm
anecen, especialmente los relacionados a la falta de personal
disponible para patrullar la playa para prevenir la extracción ilegal de nidadas y la
cacería de hembras anidantes, y la falta de apoyo por parte de las instituciones
gubernamentales, como el se
rvicio nacional de guardacosta. En las raras
ocasiones que los guardacostas estuvieron presentes lograron hacer algunos
arrestos, lo que que tuvo un impacto positivo reduciendo considerablemente las
actividades ilegales de extracción de nidadas y cacería d
e tortugas. Bajo este
escenario, la continuidad de las actividades directas de conservación, como
patrullaje nocturno, construcción y cuidado de vivero por parte del proyecto
apoyado por los ciudadanos científicos, la comunidad local son críticas para la
s
upervivencia de las tortugas marinas en Pacuare y en otros lugares.
LAST y Biosphere Expeditions continuaran con el proyecto en Pacuare para salvar
el mayor número de nidos posibles y combatir al saqueo de nidadas y la cacería de
hembras anidantes, par
a generar más información científica y así crear estrategias
para el manejo y conservación que ayuden a la recuperación de las poblaciones de
tortugas marinas. Alentamos a las autoridades a apoyar en las actividades de
conservación. Si las autoridades públ
icas ayudaran durante el patrullaje así como
con el arresto y persecución de saqueadores, el número de nidadas y hembras
protegidas incrementarían considerablemente.
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 accredited member o
f 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. Backgr
ound
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.
Annual report of the nesting activity of sea turtles in Pacuare
1
1
2.1. Introduction
and background
1
1
2.2.
Methods
12
2.3. Results
21
2.3.
1. Leatherback turtle
21
2.3.
2. Green turtle
24
2.3.
3. Hawksbill turtle
29
2.4
.
Discus
sion
and conclusions
29
2.5
.
Literature cited
35
A
ppendix 1
:
Expedition diary & reports
37
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 accredited member o
f 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, mu
ch of this section, which
remains valid and relevant, is a repetition from previous reports, 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
Bio
sphere 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 s
cientists 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 Expeditions 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
7 to 14
May
2018
with the aim of
assisting 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 beau
tiful 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
combina
tion of direct conservation action paired with
the
research
by
this programme will
assist
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
population 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 an
d eggs
(Chac
ón
2002)
. Since the first studies on nesting sea turtles on the Caribbean shores 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
be
easily 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 turtle 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 fr
om Indonesia to the U.S. in a 20,000 km foraging journey
over a period of 647 days
(Benson et al.
2011
)
. 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 accredited member o
f 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 pursue 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 Pacific 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
En
dangered. Recent estimates of global nesting populations are that 26,000 to 43,000
females 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 (consumptio
n 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 me
mbers alongside international citizen scientist
s
in its
conservation activities, recruiting 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 vuln
erable 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
protect
s nests from predation and poachers. The leatherback turtle nesting season runs
from February
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
Nu
evo Pacuare
and the local coastguards
,
and meets the standards and protocols set
by MINAET (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
oceans
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 progre
ssive (environmental) policies,
having disbanded its army and being the only country in the world 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 Environm
ental Performance Index. It was twice ranked the
best
-
performing country in the New Economics Foundation'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
-
neutral 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 i
ndigenous people he saw wore
gold bands in their noses and ears
which later led to the name of 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 s
mall 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 accredited member o
f the International Union for the Conservation of Nature
The project’s study site, 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 and 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
7
14
May
201
8
and was
composed
of a team of international
research assistants, guides, support personnel and an expedition leader (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 fo
r sleeping,
shared bathroom and shower blocks, a kitchen, hatchery and various other utility buildings.
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 spec
ial diets
were
catered
for.
Weather
Costa Rica has a tropical climate and the sun shines throughout the year. Day
temperatures during the expedition
were
between
18
and
35
° C with slightly lower
temperatures at night and humidity around
85
%
(
www.weatherbase.com
)
. There have also
been many non
-
seasonal rain events in recent years, so participants
needed to
be
prepared to work in varied weather conditions.
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 accredited member o
f the International Union for the Conservation of Nature
Field communications
M
obile phones worked
intermittent
ly on the beach.
In the field, two
-
way radios and mobile
phones were used for communication between research teams.
The expedition leader also
posted an expedition diary on
Biosphere Expeditions’ social media sites such as
Facebook
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 p
oint all transport and 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 mi
nutes 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 scien
tist for this expedition 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
de
gree
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
Id
a 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
Mas
ters degrees respectively. 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. Ex
peditio
n t
eam
The expedition 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):
Arhalous Attarian
(USA)
, Georg Berg
(Germany
, p
ress
)
, Gary Hogben
(UK)
,
Sandra
Hogben
(UK)
, Skarlet Ilieva
-
Markova
(UK)
,
Anna Kantilaftas
(Australia
, press
)
,
Eva Kohl
(Germany)
,
Stefanie
Parchmann
(Germany)
, Nicole Stinn
(Canada)
, Sherry Stinn
(Canada)
.
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 accredited member o
f 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 thanks to their contrib
ution 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 importance of marine an
d 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 o
rder 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, which runs wildlife con
servation
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 possible. The same is tr
ue 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 Fr
iends 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 keepin
g them running,
and
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
More background in
formation 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.biosph
ere
-
expeditions.org
.
Copies of this and other expedition reports can be accessed via
www.biosphere
-
expeditions.org/reports
. Enquires should be addressed to Biosphere Expeditions 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 accredited member o
f the International Union for the Conservation of Nature
1.11
. Expedition b
udget
Each team member paid
a contr
ibution of
1,73
0
per
seven
-
day
slot
towards expedition
costs
. The contribution covered accommodation 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 lug
gage charges, travel insurance, personal
expenses
such as
telephone bills, souvenirs, 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.
Inco
me
Expedition contributions
17,776
Expenditure
Staff
includes local & international salaries, travel and expenses
2,798
Research
includes
equipment
and other research expenses
109
Transport
includes
car hire,
fuel,
taxis and other local transp
ort
778
Base
includes
board and lodging at the research station
2,033
Administration
includes local sundries, fees and miscellaneous
expenses
524
Team recruitment
Costa Rica
as estimated % of PR costs for Biosphere Expeditions
8,676
Income
Expendi
ture
2,
848
Total percentage spent directly on project
84
%
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 accredited member o
f the International Union for the Conservation of Nature
Please note:
This report details the results of an entire nesting season from February to
October
2018
. The bulk of the
work
during this period
was conducted by LAST
,
with Biosphere Expedit
ions assisting during the leatherback nesting
season in May.
Please also 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 val
id and relevant, is a repetition from previous
reports, copied here to provide 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 bac
kground
Sea t
urtles are ancestral reptiles that have
been exposed to a multitude of threats over
the
last
few
decades
, which have brought many species to the verge of extinction. Humans
are a major culprit in
reducing sea turtle populations
through killin
g turtles and their eg
g
s,
utilisation of turtle parts and via other threats such as habitat loss, pollution, bycatch, boat
strikes, etc.
(Chacón
2002). With the
human population pressure
increasing in Costa Rica
,
the threats for sea turtle
populations have
also increased. For example, there is a well
-
established
black market all around the country targeting sea tu
rtle meat and eggs, with
the Caribbean side one of the most important supply zones
(Chacón 2002).
Sea turtle nesting studies in Costa Rica starte
d in the
1970
s mainly in Tortuguero National
Park
(Troëning & Rankin
2005). The Sea Turtle Conservation Project in Pacuare beach
was initiated in
2012 by Latin American Sea Turtles (LAST) in association with WIDECAST
and the Asociación par
a el Ambiente de
Nuevo Pacuare.
The project involves the
community in conservation activities as research assistants or
as staff
managing the
hatchery. The community in Pacuare
is highly vulnerable, due to
lack of jobs,
low levels of
education, as well as drug use and traf
ficking
. During
the sea turtle
nesting season
,
individuals
from nearby areas,
by and large
outside the local community,
come to the
beach to poach eggs and hunt sea turtles
,
which increase
s
pressure.
Because of this, effective
conservation activities are
critically
important for the protection
and survival of the four species present in Pacuare beach: hawksbill turtle (
Eretmochelys
imbricat
a
), green turtle (
Chelonia mydas
), leatherback turtle (
Dermochelys coriacea
) and
loggerhead turtle (
Caretta caretta
) (
Marion and
Chacón
2013
, Fonseca and Chacón 2014
).
Due to population decline around the world, t
he hawksbill turtle
is
catalogued
as Critically
Endangered; green turtle
is classified as V
ulnerable and
loggerhead turtle
as E
ndangered.
Leatherback turtles of
the Northwest Atlantic were
classified
as V
ulnerable
(from
Endangered)
in
the
2014
assessment
by the Convention of the S
ea Turtles Specialist
Group of
I
U
CN
,
due
to population recovery, mostly in Guyana, Trinidad and Tobago,
Panama
and Surinam
. However,
in
the last assessment
in 2018,
l
eatherback turtles
of the
Northwest Atlantic
were
catalogued
as Endangered by the
IUCN
Northwest Atlantic
Leatherback Working Group
,
due
to
declines in nesting abundance caused by
anthropogenic sources, habitat losses and chan
ge
s
in life history parameters (Northwest
Atl
antic Leatherback Working Group
2018).
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 accredited member o
f the International Union for the Conservation of Nature
The main objective of the project is to improve the conservation status of the sea turtles in
Pacuare beach through
citizen science and
the support of government institut
ions
,
as well
as the local community.
Specific tasks are to increase the
reproductive success of sea
turtles
by protecting nesting
females
and their eggs
. Citizen scientist
s
play an imp
ortant
role
in this and the
success rate of the
project is directly
lin
ked
to
the number of
volunteers
on the beach each year.
The
presence of
citizen scientists
is the project’s
first line of
defence against
poaching. Other critical tasks performed by citizen scientists are
data
collection, as well as
beach and hatchery main
tenance.
2.2. Methods
From February until November
2018
, daily nightly patrols were
organis
ed to monitor the
7.1 km
of beach administrated by LAST
/
WIDECAST. National and international
citizen
scient
i
sts
were involved in
beach patrols,
data recording,
measurement of nesting females
and hatchlings, as well as nest relocation and maintenance of the hatchery. Such
involvement is a key element of the project, since none of the nests can be left
in situ
due
to the high poaching activities in the area.
Citi
zen scientists
were
trained
for a day or so
upon arrival and then conduct
ed
most
activities under the supervision of a trained staff member in order to reduce bias and errors
in data recording. Evans and
Birchenough et al.
(2001) have demonstrated that, gi
ven
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 ca
nton 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 and the Pacuare River mouth in the south.
It is a dynamic beach,
susceptible to erosion during high tides. The
beach study site
was
geographically divided
into three se
ctions known
in
the project as:
Sector 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, m
aking nesting activities very challenging for turtles.
In order to facilitate
accurate localisation of
nesting activities, the beach is
further
divided
in
to
sectors of 50 metres following a
line
parallel to the sea.
At
each
dissect between
sectors
, a woo
den marker carrying
a consecutive number
is
set
.
Numbers
run from the
n
orthern
(Laguna Perla at the
Parismina River mouth
) to the southern limit (Pacuare River
mouth).
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 accredited member o
f the International Union for the Conservation of Nature
Figure 2.2a.
Pacuare beach study site and sectors.
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,
identification 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 the season,
national and international citizen scientists
were trained by the resident
biol
ogist and
the
research assistants.
On patrols, data
collection
and activities were
supervised by a trained
research assistant
.
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 accredited member o
f the International Union for the Conservation of Nature
Figure 2.2b.
Training session
for expedition citizen scientists
.
Hatchery
Figure 2
.2c
.
Hatchery.
Photo courtesy of Georg
Berg.
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 accredited member o
f the International Union for the Conservation of Nature
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 predators or turtles. During c
onstruction, 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 into 210 squares of 50 x 50 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 i
nfestations.
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 trained 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
to
not
miss out on any activity. Only red lights and dark clothing were used
while recording
biometrics, tagging nesting females, relocation of clutches and release of neonates.
If a
patrol found a
poacher
who
was already
with a
turtle,
and in line with LAST’s strict non
-
confrontation
policy,
the patrol either waited until the ov
iposition 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 were
relocated
to an alternat
iv
e 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
divided into
four categories,
in situ
or natural, reloca
ted at the beach,
ex situ
and relocated
to
the
hatchery
:
The
in situ
nests were
those
left in the
original
place selected by
laying
females at
the time of ovoposition. In Pacuare
,
in situ
nests
were
those
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
eggs later on.
N
est
s
relocated
at the beach
were
tho
se
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
were
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 beginning of the season whilst the hatchery was being b
uilt
.
N
ests
relocated
to
the hatchery
were
those
removed from their original locations
and transferred into the hatchery.
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 accredited member o
f the International Union for the Conservation of Nature
Egg collection
Figure 2
.2
d
.
Egg collection
.
Photo courtesy of Georg Berg.
When
patrols found
a turtle
without a
poacher pres
ent, 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. Biometric data wa
s then collected.
Biometrics
Figure 2
.2
e
.
Curve c
arapace length (left) and
curve carapace
width measurements (right).
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 accredited member o
f the International Union for the Conservation of Nature
After oviposition, the carapace width and length of the nesting female was measured as
shown in Figure 2.2e. Each measurement wa
s repeated three times and dictated clearly to
the citizen scientist in charge of writing down the data.
Figure 2
.2f
.
Measuring biometrics
.
Photo courtesy of Georg Berg.
Tagging
Before tagging, all turtles were checked for Evidence of Previous Taggin
g (EPT) and all
information
was
recorded onto the data sheet in accordance with protocol R
-
055
-
2007
(Chacón
et al. 2007
)
as
recommended by
SINAC
(Sistema Nacional de
Á
reas de
Conservación
).
Ne
sting female
s
without tags, or those who were about to lose tags, were
tagged 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
taggi
ng licence issued by
MINAE
(Ministry of Environment of Costa Rica).
Figure 2.2g
.
Placement of the metal
tags in the uropigeal area of a leatherback turtle.
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 accredited member o
f the International Union for the Conservation of Nature
Clutch relocation
Once a clutch of eggs wa
s 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
carefully
in order
to avoid movements that could
damage the eggs and
cause the aborti
on of the embryonal
development. Onc
e at the hatchery, one of the 21
0
squares 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 were 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 em
ergence (Fig
ure
2.
2
c
).
Figure 2
.2h
.
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
neonate
emergence.
Neonates were released at different parts around the beach
so as
to not create
known
feeding areas for predators. The
neonates
were released at a minimum distance of 1
0
metr
e
s from the high tide line so they could impri
nt on the beach
.
During nigh
t
time
release,
no
light
was used
to avoid disorientati
ng
the
neonates
. D
uring
daytime,
neonates
were
kept until 17:00 (when temperature was lowering)
, except on
cloudy or ra
iny
days
when
daytime releases were allowed if the temperature was low
enough
.
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 accredited member o
f the International Union for the Conservation of Nature
From every nest, 15
neonates
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 possible
to
avoid stressing or
disorient
ing
them
.
Figure 2
.2i
.
Measuring a hatchling.
Exhumations
E
xhumations
(Figure 2.2k
)
were
performed
on all hatched nests
to evaluate the
percentage o
f
neonates
emerged
, the number of
live/dead
neonates
remain
ing
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
neonates
had emerged.
From
ever
y
nest, the number of
egg shell
s
,
live neonates
and dead neonates were
recorded
.
Eggs that had not hatched were opened to estimate emb
ryonal development
(Figure. 2.2j
).
Figure 2
.2
j
.
Development stages of the embryos in non
-
h
atched eggs (
Chacón et al
.
2007)
.
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%.
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 accredited member o
f the International Union for the Conservation of Nature
The percentage of hatching and emergence
was
calculated following the formula:
Where PE = percentage of hatching, PEM = percentage of emerg
ence, C =
empty
shells,
N = total number of eggs and TM = number of dead hatchlings present in the nest or its
surrounding
area
.
Figure 2
.
2k
.
Conducting an exhumation count.
Research permits
On 2 March
2018, LAST submitted
an
application for the rese
arch permits required by the
Área de Conservación La Amistad Caribe (ACLAC) in order to monitor
sea turtle
species
present in Pacuare.
P
ermission
was granted
on
4 March 2018
under resolution
R
-
SINAC
-
PNI
-
ACLAC
-
010
-
2018
signe
d by Jorge Gonzáles Villalobos.
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 accredited member o
f the International Union for the Conservation of Nature
2.3
. Results
2.3.1
.
Leatherback turtle (
Dermochelys coriacea
)
Number of nests
A total of 392 nesting activities were recorded during the 2018 season in Pacuare beach,
of which 241 were successful and
resulted in
viable nests. Compared with the pr
evious
seasons, the 2018 season’
s data
were
slightly below average. The number of nesting
activities in the season correspond
to the inter
-
annual fluctuations described previously by
several authors (Troëng
et al
.
2004,
Chacón
-
Ch
averri and Eckert
2007) (Figure 2.
3.1a
).
0
100
200
300
400
500
600
700
800
900
2012
2013
2014
2015
2016
2017
2018
Season
Number of nesting activities
Tota l a cti viti e s
Numbe r of ne s ts
Figure 2.3.1a
.
Leatherback turtle nesting activities
at
Pacuare beach since 2012.
The months with highest amount of nests were April and May with 103 and 60
nests
respectively (Figure 2.3.1b
). No nests were recorded during the month of February
, 49
nests were registered in March,
24 in June
,
four
in July and
one
in August. As
during the
four previous seasons
,
the nesting pattern
observed at
Pacuare beach
was
similar to the
one
at
Gandoca beach,
w
h
ere 71
% of the nests were recorded in A
pril and M
ay (Chacón
-
Chaverri and Eckert 2007, Fonseca
et al.
2012, Marion and Chacón 2013,
Fonseca
and
Chacón
2014
, Marion and Chacón 2016, Carrasco and Chacón
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 accredited member o
f the International Union for the Conservation of Nature
Figure 2.3.1b.
Seasonal distribution of
nesting activity for l
eathe
rback turtle
at
Pacuare beach during 2018.
During the 2018 season, nesting activities were recorded along all 144 wooden markers.
The
marked parts of the beach
with the
highest
activity were
0
-
10, 51
-
60 and 81
-
90
(Figure 2.3.1c
). The spatial distribution
of the nesting activity continues
to be
a challenge
for the project
,
because more staff and
citizen scientist
s
would be needed in order to
successfully cover
all the
7.1 km of beach throughout the whole night
in order to thwart all
poaching efforts.
F
igure
2.3.1c
.
Spatial distribution of
nesting activity for l
eatherback turtle
at
Pacuare beach 2018 season
.
Blue bars correspond to sector A, green bars to sector B and yellow
bars to sector C (see Figure 2.2a
).
0
20
40
60
80
100
120
140
160
180
February
March
April
May
June
July
August
Number of nesting activities
Number of nests
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 accredited member o
f the International Union for the Conservation of Nature
Number of nesting females
A total of 134 n
esting females were
recorded
during the season, 29
of which
did not show
any tag or
evidence of previous tags. These
additional
females are likely to be
new
females that
have reached sexual maturity, replacing
dead or poached individuals
, which
would be
a
good
sign for the
Caribbean population of
leatherbacks in
Costa Rica
and
Panama
.
Unfortunately, there are no
studies that estimate sea turtle mortality in
the
area.
Of the 134 nesting females recorded
over
the season, 97 laid only once, 23
twice and 12
thr
ee times. O
ne turtle laid five times and another turtle six times
(Figure 2.3.1d
).
0
20
40
60
80
100
120
1
2
3
4
5
6
Number of nestings recorded
Figure 2.3.1d
.
Number of
nesting
s
recorded per female leatherback turtle
at Pacuare beach
i
n 2018
.
Nest
fate
The percen
tage of protected nests was 65
%
(n = 155)
of the
total a
mount of nests in the
season. T
his percentage
of saved nests
is the
highest
since
the project started in 2012
(Figure 2
.3.1e)
.
Of the sa
ved nests
,
89
%
(138
nests)
were reloc
ated to the hatchery and
11
%
(17 nests)
were relocated to a safe place on t
he beach. The majority of nests were
guarded at the hatchery
,
because the protection and control provided in the hatchery is
better
. P
oachers
hide
in the vegetation
at night
to avoid
detection. If a nest is relocat
ed
,
this can be seen by poachers who can t
hen poach the eggs once workers have finished
with the beach relocation and left the site.
44.94
54.06
40.57
37.11
52.83
58.06
64.7
30
35
40
45
50
55
60
65
70
2012
2013
2014
2015
2016
2017
2018
Season
Percentage of saved nests
Figure 2.3.1e
.
Percentage of saved
leatherback
nests
at
Pacuare
over time.
24
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
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f the International Union for the Conservation of Nature
Nest hatching and emergence success
The emergence success
of
leatherback nests was 67% (SD = 21.52, n = 155),
including
hatchery
and beach relocations
. 8,112 neonates
emerged from these nests
.
The emergence success of the nests inc
ubated in the hatchery was 69%. T
his percentage
is
the second highest percentage
since 2012 (Figure 2.3.1f) and
higher tha
n the
percentag
e recorded in Gandoca (Chacón and Eckert
2007) and Tortuguero (Troëng
et al
.
2007),
where the emergence success
was between 11 and 39% and 42.6 ±
35%
respectively.
Figure
2.3.1f
.
Emergence success of
saved
leatherback
nests
at
Pacuare
over time.
2.3.2
.
Green turtle (
Chelonia mydas
)
Number of nests
126 nesting activities of green turtles (
Chelonia mydas
) were
recorded, of which 42 ended
up as
successful nest
s
.
Disturban
ce by poachers for this species
remains
high
as
poachers arrive specifically for the green turtle nesting season
, with turtles too
scared
to
nest
or killed before or while nesting.
79
99
52
32
136
72
42
0
20
40
60
80
100
120
140
160
2012
2013
2014
2015
2016
2017
2018
Season
Number of nests
Figure 2.3.2a
.
Green
turtle nesting activiti
es
at
Pacuare beach since 2012.
62.67
60.32
48.86
73.69
50.88
63.92
69.28
0
10
20
30
40
50
60
70
80
2012
2013
2014
2015
2016
2017
2018
Year
Emergence success
25
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
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Officially accredited member o
f the International Union for the Conservation of Nature
Nesting activity is shown in
Figure 2.3.2b
. This is a similar pattern
Tortuguero
, where the nesting peaks
in September and October
(González and Harrison
2012).
0
4
2
17
17
2
0
10
20
30
40
50
60
May
Jun e
Jul y
Augus t
Se ptember
Octob er
Num be r of n es ti n g a cti viti e s
Numbe r of ne sts
Figure
2.3.2b
.
Seasonal distribution
of nesting activity for
green turtle
at Pacuare beach during 2018
N
esting activity was
highest on
se
ctors 11
-
20 and 21
-
30 (Figure 2.3.2c
). 55% of nests
were
in the north
ern
part of the beach (after the second lagoon).
There were no nests in
the sectors ne
ar
Pacuar
e r
iver mouth (121
-
130 and 131
-
144
).
0
7
10
4
2
5
4
3
2
2
2
1
0
0
0
2
4
6
8
10
12
0-10
11-20
21-30
31-40
41-50
51-60
61-70
71-80
81-90
91-100
101-110
111-120
121-130
131-144
Be a ch s e cto r
Num ber of nes t
Figure
2.3.2
c.
Spatial distribution of
nesting activity for green
turtle
at
Pacuare beach 2018 season.
Blue bars correspond to sector A, green bars to sector B and yellow
bars to sector C (see Figure 2.2a
).
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 accredited member o
f the International Union for the Conservation of Nature
N
umber of females
27 female turtles were recorded
,
of which 22 nesting
turtles did not present any tag or
evidence of previous tagging.
Number of turtles killed
Ten
nesting females were killed by poachers,
an overall low number
(
see
Figure 2.3.2d
),
wh
ich becomes average when considered as a percentage of females killed
compared
with previous seasons
(Figure 2.3.2e
).
44
10
22
16
40
10
10
0
5
10
15
20
25
30
35
40
45
50
2012
2013
2014
2015
2016
2017
2018
Season
Number of killed turtles
Figure 2.3.2d
.
Number of green turtles
killed
at
Pacuare
since 2012.
0
2
4
6
8
10
12
14
16
2012
2013
2014
2015
2016
2017
2018
Season
Percentage of killed turtles
Figure 2.3.2e
.
Percentage
of green turtles killed at Pacuare s
ince 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 accredited member o
f the International Union for the Conservation of Nature
The c
oast
guard
, alerted by a community member,
rescued a green turt
le female and two
green turtle
nests
, b
oth
nests were
from turtles that
had been
killed by poachers
only a few
hours
prior
.
Two persons were arrested and charged.
We do not know
whether the
charges resulted in convictions, but the two persons arrested did not return to the beach
for the rest of the season.
Two dead turtles were found on the beach in August. O
ne of them wa
s already
too
decomposed (Figure 2.3.2f
)
to determine caus
e of dea
th
. T
he second
had a
cracked
carapace from the nuchal scute to the
last vertebral scute (Figure 2.3.2g
)
,
possibly caused
by a powerful impact against to a solid obje
ct, such as a boat strike.
Figure 2.3.2f.
Decomposed g
reen turtle
.
Figure
2.3.2g.
Green turtle with carapace broken
.
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 accredited member o
f the International Union for the Conservation of Nature
Nest fate
69% of green turtle
nests were protected in 2018. 29 nests were moved to the hatchery
,
out of which,
27 were collected during the night patrols
and two were rescued
by
the
coast
guard
. No nest were relo
cated on the beach.
Nest hatching and emergence success
The percentage of emergence from
exhumed
nests
was 74
% (SD = 20.23, n = 24),
releasing approximately 2,038 neonates. Compared with the previous seasons this
percentage is average (Figure 2.3.2h
).
97
% was
t
he highest emergence percentage; t
his
nest was collected
in September. T
he lowest percentage
(13%) was from a nest collected
in August
. The
two nests sa
ved by the c
oast
guard had a
low average
percentage of
emergence of 18
%
,
because the
eggs of the
second ne
st
did not develop,
as
they spent
14 hours in the open between being extracted and given to the project for nest transfer to
the hatchery.
Figure 2.3.2h
.
Emergence success of
saved
green turtle
nests
at
Pacuare
over
time.
81.59
71.55
72.63
72.63
80.83
71.1
73.7
6
4
66
68
70
72
74
76
78
80
82
84
2012
2013
2014
2015
2016
2017
2018
Season
Percentage of emergence
29
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-
for
-
p
rofit conservation organisation
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Officially accredited member o
f the International Union for the Conservation of Nature
2.3.3
.
Haw
ksbill t
urtle (
Eretmochelys imbricata
)
Number of nests
21 nes
ting activities were registered,
out of which 13 were successful. Six nests were
placed in the hatchery, two nests were poached and five nesting females were killed by
poacher
s. This season was similar to the
seasons 2014 and 2017 (Figure 2.3.3a
).
0
5
10
15
20
25
2012
2013
2014
2015
2016
2017
2018
Ne s ti ng a cti viti e s
Re l oca te d n es ts
Poa che d ne s ts
Kill e d turtles
Figure 2.3.3a
.
Nesting activity, number of relocated nests, number of poached nests
a
nd number of killed hawksbill turtle at Pacuareover time.
Nest hatching and emergence succ
ess
The percentage of emergence of
exhumed nests was 88
% (SD = 20.78, n = 6)
,
releasing
an estimate
d
810 hatchlings. The nest with
the
highest emergence percentage
(93%)
was
laid in May
, as was
the nest with lowest emergence percentage
(75%) of the season
. The
latter
was buried in a zone in the hatchery where shade was always present
,
which could
explain the low emergence success.
2.4. Discussion and conclusions
Leatherback turtle
A total of 392 nesting activities of leatherback turtl
es were recorded t
hroughout the
season, out of which 138 nests were placed in the hatchery and 1
7
in a safe place at the
beach. F
rom
all
nests, 8,112 neonates were rele
ased into the ocean. The emergence
success was
67
%
(SD = 21.52, n = 155
), including the ne
s
ts relocated at
the beach and
the nests placed in the hatchery.
30
© Biosphere Expeditions, an international not
-
for
-
p
rofit conservation organisation
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Officially accredited member o
f the International Union for the Conservation of Nature
I
llegal harvesting of eggs
was at 35%, which means that 65
% of clutches were protected
by the project
’s
direct conservation actions. This percentage of saved nests is the highest
since the project started i
n 2012 (Figure 2.3.1
e).
The data recorded
at
Pacuare beach since 2012 indicates that the population of
l
eatherback turtle
remains stable
, which is encouraging. However,
the
IUCN’s
Northwest
Atlantic Leatherbac
k
W
orking
G
roup has
recently shown that the le
atherback population in
general is in steep decline with a
60%
reduction in abundance
over
the last 20 years
(
Northwest Atlantic L
eatherback Working Group
2018).
This decline
places the
leatherback population of the northwest Atlantic into the
Endangered
c
ategory (IUCN
2014). Therefore, LAST and Biosphere Expeditions recommend
continuation of
monitoring
to
determine
long
-
term
effects
and effectiveness of conservation action to keep the
species from becoming extinct.
The low incidence of remigrant leatherba
ck females at Pacuare is probably because
females have
a
choice
of nesting beaches
anywhere on
the Caribbean coast of Nicaragua,
Costa Rica
or Panama
.
Dutton
et
al.
2013
have shown that t
he genetic
pool of the
Western Caribbean
runs from the s
outh of Nicar
agua
to the n
orth of Colombia. So females
can
return to nest in
a plethora of
areas where
the project does
not operate.
Green
turtle
126
nesting activities of
green turtle
were recorded
during the
2018 season. A
total of 29
nests were placed in the hat
chery, from those nests
approximately 2,038 neonates
emerged and were released into the ocean.
The emergence success was
74% (SD =
20.23, n = 24). T
his percentage is average compared with the previous seasons (Figure
2.3.2h).
The
2018
season
had
the second
lowest green turtle
numbers
recorded at
Pacuare beach since LAST started running the project in 2012,
with
only
the
2015 season
being lower
(Figure 2.3.2a).
The poaching rate for gr
een turtle was 31%, which means that 69
% of
nests were saved
by the proje
ct’
s direct conservation actions.
This is a very positive result given the
resources and one that the project and its citizen scientists can be proud of. As with
leatherbacks, challenges remain, especially those related to human resources to patrol the
bea
ch and prevent poaching
.
Because of the lack of resources, t
en green turtles were
killed by poachers
this season. In addition
two dea
d turtles appeared at the beach,
probably killed by boat strikes.
This shows
that
direct conservation action
at Pacuare
bea
ch must continue in order to reduce
illegal harvesting of eggs and slaughtering of
nesting females.
The project is working with the police and c
oast
guard to
reduce
illegal
activities in Pacuare beach and create a safe environment for
all.
In 2018
the c
oas
t
guard
rescued one nesting female captured
the
night before
,
when
she was trying to lay her
eggs, and two nests from turtles that had already been killed
.
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 accredited member o
f the International Union for the Conservation of Nature
Hawskbill
turtle
21 nesting activities of hawksbill turt
le were recorded.
From
six
clutches move
d to the
hatchery,
810
hawksbill neonates emerged
and were successfully released
in
to the ocean.
The emergence percentage was
88
% (SD = 20.78, n = 6)
.
The poaching rat
e for hawksbill turtle was 54
% (including killed turtles and poached nests).
This is of
concern as only 46% of nests could be saved
. One of the reasons
for this is the
c
oast
guard and p
olice
absence
throughout
almost all of
the season.
More presence of
these law enforcement bodies would mean better success in protecting turtles and their
egg
s from poaching (see the green turtle example above).
Fi
ve hawksbill turtles were killed
by poachers
to sell their carapaces
on
the black market
.
The nesting activity in 2018 was similar to the
2014
and 2017
seasons
.
This
season was
the second year in a
row
that
five nesting females were killed (
the
highest number of
hawksbill turtles killed in a season)
and is a cause for concern
.
Loggerhead turtle
No
loggerhead turtle activity was recorded
at
Pacuare, which
corroborates our hypothesis
that the
nes
t r
ecorded in 2017 season was an isolated and sporadic event
.
Overall efforts
173
clutches
of three
different sea turtle species
were relocated
to
the custom
-
built
hatchery,
1
7
were relocated to a safe place
on
the beach
and none were left
in situ
because
of the high
poaching rate.
O
verall 60
% of all nests of th
e 2018
season across
the
three
sea turtle species were saved by the project’s direct conservation action.
This
percentage is a good result given the resources available and one the project and its
ci
tizen scientists can be justifiably proud of.
However, with the support of the police and coast guard, this percentage could easily be
higher, especially because
the Costa Rican state is the only
body
that can take
direct
actions against poachers, such
as arresting and prosecuting them (whereas this project
has a non
-
confrontation policy). Sadly, the police and coast guard were almost completely
absent from the beach throughout the nesting season. We encourage them to change this
and be more proactive in
turtle conservation, especially given their considerable resources
and manpower.
Additional technology
During th
e
2018
season and in accordance with the 2017
recommendations, we trialled a
handheld forward
-
looking infrared (
FLIR
) device
to
try to
spot
green and hawksbill turtles
hidden by poachers
in
the vegetation or
in
the canal
s
.
Unfortunately the low number of
green and hawksbill turtles and the extreme weather at Pacuare
made
using
the device
almost impossible.
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 accredited member o
f the International Union for the Conservation of Nature
Discussion
The number of protected nests and hatchlings released
are a big achievement for LAST
and its partners. T
he project has been
active
for seven years
now and in this time
w
as
able to very significantly
reduce
the p
oaching of nests and nesting females in a place
where tho
se activities were very common
;
almost 100% of turtles arriving at the beach and
their eggs were poached prior to 2012.
Having said th
at
, poaching remains an issue
.
D
ata
recorded
since 2012
strongly
indicate
tha
t
Pacuare beach is one of the most important nesting
turtle
sites
in Costa Rica
,
for the
leatherback turtle
in particular, but
also for o
ther sea turtles
(Marion and Hammer 2016
)
.
The continuation of poaching
is explained by several factors,
which are:
The absence of authorities in charge of the protection of the natural resources in
the zone includin
g the National Service of Coast G
uards (SNG), Instituto
Costarricense de Pesca y Acuicultura (INCOPESCA) and the Ministry of
Environment and E
nergy (MINAE).
The lack of en
forcement, most of all by police,
in the law of wildlife protection (Law
7317) and the law of protection, conservation and sea turtles recovery (L
aw
8325).
T
he project’s
limited
resources, both in terms of finance and manpow
er, meaning
that not all 7.1 km of beach can be patrolled all the time, leaving opportunities for
poachers.
The
low
number of job
and other
opportunities in
the area,
which
makes criminal
activities that generate income more likely and acceptable socially
.
T
he high
value of
turtle eggs and meat
on
the black market
coupled with the virtual
absence of law enforcement provides a strong incentive for poachers to continue to
ply their lucrative trade in what are
very poor and disadvantaged resident and
transie
nt communities along Pacuare beach.
In this context it is important to note
that
most of the individuals involved in poaching
appear to
have a criminal record
already
(as ascertained through personal communication and observation), with a
concomitant low t
hreshold towards further illegal activities.
All of the above
factors
result in
an ongoing
, if successful, struggle of NGOs against
what
appear to be mainly
transient and criminal poachers, many of whom
appear to
sustain
an
alcohol and drug addiction
,
thr
ough the depletion of the
sea turtle
population.
As long as
NGOs are by and large left to continue this struggle by themselves
, poaching will remain a
problem and nests will continue to be poached
. Despite this, and given enough future input
from internati
onal volunteers and citizen scientists, many nests will continue to be saved
and many hatchlings will be helped into the ocean, thereby preventing the local extinction
of sea turtle populations.
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 accredited member o
f the International Union for the Conservation of Nature
If, however, the national authorities tasked with nature pr
otection and law enforcement
were to join efforts in turtle conservation, then
the project
could be turned from extinction
prevention
in
to population recovery.
In the opinion of the authors, combined action will
have a high chance of success in bringing po
aching down to levels below
10
%.
Because of this, the project in 2018
work
ed
closely
with
the
coast
guard
. Every time
turtle
or egg poaching was noticed
,
project staff
called the coast
guard to try to save the turtles
and arrest the poachers. As a result
two poachers were arrested and
charged with wildlife
protection offences
.
However, limited coast guard resources, especially in manpower,
prevented them from attending to many of the project’s calls for help
. Despite this,
anecdotal evidence suggests that
poachers are becoming more war
y
and
are
spending
less time poaching.
Even a slight increase in authority involvement is to be welcome
d
and appears to be
producing results
.
Ideally
authorities should be proactive in the
removal of transient,
crimin
al poach
ers 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
a
nd economic development of the community of Pacuare is a crucial parameter to allow
the project
to meet its obje
c
tives and
to
protect the population of sea turtles.
We
also
recommend the creation of
ecotourism activities, such as
English classes for
loca
ls 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 activities 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
donate a percentage of the income provided by the internat
ional 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 local
guides
,
but the month of April, which is the beginni
ng 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 part
ners
, 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 livelihood to the community
of Pacuare.
It is also crucial
to reintroduce
a successful
program
me
of environmental education in the
area.
Its
absence due to lack of financial resources and disinterest of partners such as
banana plantations and commerce is
already
affecting the younger
residents
of
the
Limón
area
.
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
human waste
. If th
e municipality could
remove these itinerant persons, they would be contributing to the reduction of the illegal
extraction of eggs and killing of
turtles
.
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 accredited member o
f the International Union for the Conservation of Nature
The accumulation of rubbish on the beach
could be prevented by setting up an effective
collection s
ystem 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
2019
season
LAST and Biosphere Expeditions rec
ommend 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 bea
ch.
The
use of
a
handheld forward
-
looking infrar
ed (FLIR) device should be used
mostly on green and hawksbill turtles along with
the
coast
guard or police
. I
f the
device is used
in conjunction
with the n
ational authorities,
the success rate of saved
turtl
es
could
increase considerably. Also
,
poachers
are more likely to
be caught and
arrested
with the use of FLIR technology
.
Continu
ed
nurturing of
the
existing
relationship with the c
oast
guard
is critical, so
that the joint
efforts of law reinforcement au
thorities
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 activiti
es and support the community in
developing itself to attract eco
-
tourism and voluntourism.
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 accredited member o
f the International Union for the Conservation of Nature
2.5
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© 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 accredited member o
f the International Union for the Conservation of Nature
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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 accredited member o
f the International Union for the Conservation of Nature
Appendix 1
:
Expedition diary & reports
A multimedia expedition diary is available on
https://blog.biosphere
-
expeditions.org/category/expedition
-
b
logs/costa
-
rica
-
2018/
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.
Article
1. Traditional community-based systems of managing coastal fisheries were (or in some cases are) successful in managing resources at sustainable levels. These systems are used as models in the present study. 2. They were (or are) under-pinned by a sense of ownership and intimate knowledge of the environment in local people. 3. Such features have been largely lost, as subsistence economies have been replaced by capitalist ones, and environmental management responsibilities have shifted from local communities to national or international government. 4. There are, nevertheless, some examples of community-based management systems that still operate successfully and we believe that modern management practices, in general, would benefit from increased community involvement. This will require renewed emphases on feelings of ownership and increased knowledge of the environment in the general public. 5. Environmental education will have a fundamental role to play in achieving this goal. However, its impact in schools and universities has been disappointingly ineffective so far in promoting a population that is sufficiently knowledgeable and well-motivated to partake meaningfully in environmental management processes. 6. It is argued that educational initiatives, which involve all ages and sections of society, are required. Five promising possibilities are: (i) the participation of community groups in scientific projects; (ii) increased emphasis on life-long learning; (iii) educational campaigns; (iv) citizens' juries; and (v) the involvement of community groups in environmental planning and management processes. 7. Wide-scale adoption of innovations of these kinds will require funding and this will be achieved only by national re-assessments of educational needs and priorities. Copyright
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.