Partnership Year Report Laamu 2019-20 - Protecting sea turtles and their habitats in the Indian Ocean - Six Senses
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Protecting sea turtles and their
habitats in the Indian Ocean
Partnership Year Report
Laamu 2019-20
Jo Goodfellow, Martin Stelfox & Jillian Hudgins
TABLE OF CONTENTS
SECTION PAGE
About The Olive Ridley Project 3
Executive Summary 4
Glossary of terms 5
Introduction 7
Methods 8
Population research - results 11
New IDs 12
OUR RESEARCH
Species discovery curves 13
Population structure 14
Capture-mark-recapture 17
Encounters per hour by site type 21
Sightings per hour by site type 25
Population research - discussion 28
Capture-mark-recapture 29
Encounters and sightings per hour by site type 30
Priority survey sites 31
Nesting, entangled/injured turtles and ghost net research 34
Nesting 35
Entangled/injured turtles and ghost nets 35
Education and outreach 37
Community 38
Guests 39
Hosts 42
Future direction 43
References 45
Cover photo: © Alex Mustard
ABOUT THE OLIVE RIDLEY PROJECT
The Olive Ridley Project (ORP) is a UK registered
charity established in 2013. Our vision is to protect
sea turtles and their habitats in the Indian Ocean.
ORP operates in several regions of the Indian Ocean including the
Maldives, Kenya, Oman and Pakistan. We focus on research,
rehabilitation, education and outreach. We operate a Marine Turtle
Rescue Centre and a Sea Turtle Rehabilitation Centre in the Maldives.
We are a team of turtle biologists, veterinarians and conservationists
that use our knowledge to safeguard sea turtles and their habitats.
© Alex Mustard
RESEARCH
We have one of the largest sea turtle ID and ghost net © Leanna Crowley
databases in the Indian Ocean.
Our research areas include:
● Photo identification (population research)
● Nesting
● Genetics/isotopes
● Ocean modelling
● Ghost gear modelling
● Parasitology
● Turtle behaviour
● Satellite tagging
● Sea turtle veterinarian science
PARTNERSHIP WITH SIX SENSES LAAMU
© Alex Mustard
ORP and Six Senses Laamu have been working
together to protect sea turtles and their habitats
since April 2018.
Our permanent presence in Laamu enables ORP to maintain Laamu’s
photo ID database, monitor turtle nests and conduct educational
awareness in the region. ORP aims to better understand the size of
Laamu’s nesting and foraging turtle populations and to identify turtle
hotspots.
In Laamu, ORP forms part of the Maldives Underwater Initiative (MUI).
MUI combines the research and conservation efforts of the marine
biology team at Six Senses Laamu and the resorts three partner NGOs:
Manta Trust, Blue Marine Foundation and Olive Ridley Project.
EXECUTIVE SUMMARY
Here we report on the research, resort and community Monthly variation in the number of sightings and
activities conducted by ORP during the 2019-20 encounters at channel corner and outer reef sites could be
partnership year (April 2019 - March 2020). Where explained by seasonal shifts in population size. Increased
possible we make comparisons to previous partnership - survey effort over multiple years is required to accurately
and non-partnership - years. identify seasonal trends in population size.
During the 2019-20 partnership year, 1,652 turtle Our partnership with Six Senses Laamu relies on building
encounters (visual observations with accompanying ID capacity and nurturing sea turtle experiences in Laamu.
photographs) and 5,264 turtle sightings (visual Through this we aim to put sea turtles in the spotlight and
observations with or without accompanying ID photographs) encourage the protection and conservation of sea turtles in
were recorded. 153 new individual turtles (60 green and 93 the Maldives and beyond. Though our partnership we are
hawksbill) were added to the Laamu ID database, bringing able to reach local communities through workshops and
the total number of unique individuals to 527 (201 green festivals to teach Maldivians about the perils of sea turtles
and 326 hawksbill). Laamu hosts the fourth largest and the need for protection. We have reached a wide
database in the Maldives, and the second largest green variety of nationalities through our nest hatching events
turtle database. and turtle snorkels, and continue to develop new and
innovative ways to spread our message.
Hithadhoo West and Olhuveli Reef appeared to approach
saturation for newly identified green turtles in 2019-20, We hope that through our partnership with Six Senses
whilst Hithadhoo Corner saw a spike in newly identified Laamu we are able to establish a long term dataset that
individuals. In comparison, there was a steady increase in will help inform policy and future management of sea turtle
the number of newly identified hawksbill turtles across all populations in Laamu.
sites in 2019-20. Adult females dominate the green turtle
population in Laamu however juveniles make up the
- Dr. Martin Stelfox, ORP CEO and Founder
majority of hawksbills identified. Interestingly, apparent
survival was much higher for green turtles (~90%) than for
hawksbill turtles (76%). It is unclear if this is due to
increased mortality or increased emigration.
GLOSSARY OF TERMS
Abundance curve Chart used by ecologists to display relative species abundance - how common an
organism is in a particular location
Apparent survival The probability that an individual in the population at time i is still alive at time i+1.
Apparent survival implies that true mortality (death) and permanent emigration
(movement away from a home reef) cannot be identified from one another.
Channel Atoll opening that leads from the inside to the outside of the atoll rim
Channel corner Outer edge of larger channels
Closed population Population which does not allow for movement in and out (no immigration or
emigration)
CMR
TURTLECapture-Mark-Recapture
RESCUE & REHABILITATION
CV Coefficient of variation - statistical measure of the dispersion of data points around
the mean. Illustrates the extent of the variability of the data.
DBD Deep Blue Divers - dive centre based at Six Senses Laamu
Detection rate Frequency of detection events (photographs) for an individual
Discovery curve Visual representation of the cumulative number of individuals identified over time
Encounter Visual observation of a turtle with an accompanying identification photograph
Ghost net Lost, abandoned or discarded fishing net
Giri Sea mount (shallow, flat, sandy)
Guest interaction Measure of guest engagement - attendance of one guest at an ORP-run event
Inner reef Reef slope on the inside of the atoll rim
Long-term growth rate Compound annual growth rate over the past 3.5 years (in this study)
MUI Maldives Underwater Initiative
North-east monsoon (winter Dry season in the Maldives, running from November to February. March and April are
monsoon) included in this study as a shoulder season. The north-east monsoon is known as
iruvai in the local language Dhivehi and is the high season for tourism.
Open population Population which allows for movement in and out (immigration and emigration)
ORP Olive Ridley Project
Outer reef Reef slope on the outside of the atoll rim
Partnership year 12-month period of partnership between Olive Ridley Project and Six Senses Laamu
(April - March)
R Free software for statistical computing and graphics
RD Pollock’s robust design - a method to analyse capture-mark-recapture data that
allows for the use of both open and closed population models
Recruitment Process by which new individuals are added to an existing population
RMark Package for the statistical software R. A collection of functions that can be used to
TURTLE RESCUE & REHABILITATION
analyse capture-mark-recapture data.
Saturation Maximum number of individuals that can coexist in a community given the number
and volume of resources available (also known as the environmental carrying
capacity)
Seagrass Meadow site dominated by seagrass
Sighting Visual observation of a turtle regardless of whether or not an accompanying
identification photograph was taken
South-west monsoon Wet season in the Maldives, running from May to September (known as hulhan’gu in
(summer monsoon) the local language Dhivehi. October is included in this study as a shoulder season.
Survival probability Proportion of individuals that survive beyond a specified time
Thila Sea mount (deep, pointed)
INTRODUCTION
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This report summarises the research, resort and community The research described in this report was conducted in Laamu
activities conducted by ORP during the 2019-20 partnership atoll in the south of the Maldives. Research effort was greater
year (April 2019 - March 2020). Where data are available, the in the south of Laamu, in the areas surrounding ORPs partner
report draws comparisons with the previous partnership year resort, Six Senses Laamu. Data were collected at 55 dive and
(2018-19; April 2018 - March 2019) and years prior to ORPs snorkel sites in Laamu; 45 of these sites - those with
partnership with Six Senses Laamu. recorded GPS coordinates - are visualised in Figure 1.
TURTLE RESCUE & REHABILITATION
Figure 1: Map of Laamu illustrating survey sites.
© Alex Mustard
METHODS
Data in this report can be categorised as either “encounters” collection was pursuant to research permits issued by the
(referring to visual observations with accompanying Environmental Protection Agency. The photographs were later
identification photographs) or “sightings” (referring to all used to identify individual turtles using their unique pattern
visual observations regardless of whether or not of facial scales. Matches were initially confirmed by eye;
accompanying identification photographs were taken). however, following the transfer of the Laamu database to a
global online platform in late 2019 (Internet of Turtles:
Encounter data comprised data collected by ORP and MUI.
iot.wildbook.org), matches were later confirmed using facial
Encounter data were not collected by DBD (Deep Blue Divers -
recognition software. Photographs that could not be matched
dive centre based at Six Senses Laamu) as the use of cameras
to an existing individual in the database were assigned a new
by guiding dive instructors is prohibited.
identification number. Photographs of at least the right side
Encounter data were collected on 1,088 snorkels and SCUBA of the head (ideally both sides) were required to assign a new
dives (hereafter surveys) during the 2019-20 partnership identification number. Photographs of the left side of the
year, totalling 831 hours of survey effort. Surveys included head that could not be matched to an existing individual
both research and recreational snorkels and SCUBA dives. remained in the database for future identification but were
During each survey, sighted turtles were approached slowly, not assigned a new identification number. Only encounters of
and photographs were taken. Researchers aimed to capture at individuals with an identification number were analysed.
least one photograph of each side of the face, and one Incomplete data (missing identification numbers, dates or
photograph of the carapace. The date, site and sex of the sites) were excluded from analysis. As Internet of Turtles does
turtle were also recorded. Sex was determined based upon not yet provide the option to record survey duration data,
criteria described in Table 1. Size at maturity is debated survey duration data from sightings datasets were filtered to
within the scientific community and therefore the size at exclude entries from DBD staff and used in lieu. 1,652 turtle
which sex is determinable can only be estimated. Juveniles encounters (1,119 green and 533 hawksbill) from 2019-20
cannot be sexed visually and therefore cannot be classified by were analysed in this report.
sex. Estimates in this report were based upon research
From the encounter data, a capture history was created for
conducted by Limpus and Chaloupka (Limpus & Chaloupka
each individual. If an individual was seen in a particular
1997; Chaloupka & Limpus 1997). Suggestion that hawksbill
month a 1 was entered in the capture history matrix; if it was
turtles in the Indian Ocean are smaller than their Pacific and
not seen a 0 was entered. Encounter data were first analysed
Atlantic counterparts was also considered (Hudgins et al.
using a species discovery curve - a visual representation of
2017). Data collection involved no handling of animals and
the cumulative number of individuals identified over time. The
caused no harm to, or harassment of, sea turtles. Data
reefs with the highest populations were chosen for the In this study an RD approach was applied to foraging
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discovery curves. For green turtles Hithadhoo Corner, hawksbill and green turtle encounter data to determine
Hithadhoo West, and Olhuveli Reef (including Olhuveli East, abundance and apparent survival at reefs in Laamu between
Olhuveli Seagrass and Coral Garden between which there is May 2016 and November 2019. For the RD analyses, six
movement of individuals) were chosen for analysis. For month periods (May to October and November to April) were
hawksbill turtles the three aforementioned reefs were chosen as the primary interval (aligning with the country’s
analysed along with Laama Faru Haa and Kurethi. Kurethi was monsoons to test seasonality) and one month periods for the
omitted from further analyses due to variation in consistency secondary interval. The RD meant that the population at each
of survey effort over the years, which affected results. reef was modelled as open across the primary sampling
intervals (six months) but closed within the secondary
Encounter data was then analysed using
intervals (one month) (i.e., the population was assumed to be
capture-mark-recapture (CMR) analyses. The initial
closed to additions and deletions across all months within a
photographic identification was used as the “capture” event,
six-month period (monsoon season) but open between
the “mark” was the individual identification based on the size,
six-month periods). The analysis tested 30 different models in
shape, and layout of facial scales, and the “recapture”
R [package RMark (Laake 2013)] in order to explore how
TURTLE RESCUE & REHABILITATION
referred to subsequent photographs of that same individual.
capture probability, survival, emigration, and immigration
The correct identification of individuals is a fundamental
changed over time.
assumption of CMR methods (Otis et al. 1978). All photos
taken in the field went through a categorisation to exclude As the RD analysis performs better with more data, only sites
those without turtles, those out of focus, and those in which with consistent data collection from 2016 to 2019, and with
the facial scutes were not completely visible. From CMR at least ten identified individuals, were analysed. In some
studies, populations of animals are often modelled as either cases, the first six-month interval was omitted due to paucity
open (involving movement in and out of the population) or of data. For green turtles we analysed data from Hithadhoo
closed (no movement in or out of the population). Pollock’s Corner, Hithadhoo West, and Olhuveli Reef. For hawksbill
robust design (RD) (Kendall & Pollock 1992) offers a different turtles we analysed the three aforementioned reefs plus
approach. It combines features of both open and closed Laama Faru Haa. Both species were then analysed at an atoll
population models in an ad-hoc fashion for use in long-term scale (taking into consideration that only a small portion of
studies. RD accounts for emigration, apparent survival, and the atoll was surveyed).
detection rates at once. For a more detailed description of RD
see Kendall and Pollock (1992).
Table 1: Classification of turtle encounter and sightings data.
Species Age classification Carapace length/cm Additional notes
Green Male >80 Large tail
Female >80 Small tail
Juvenile ≤80 NA
Unknown Unknown NA
Hawksbill Male >60 Large tail
Female >60 Small tail
Juvenile ≤60 NA
Unknown Unknown NA
Sightings data comprised data collected by ORP, MUI, and were recorded. If multiple staff members were present during
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DBD. Repeat sightings of individual turtles during a survey the same survey, the maximum number of sightings by any
were recorded as separate sightings. Consequently, sightings one individual was recorded. If staff members took separate
data are not representative of the true number of individuals. routes at the same site, each route was recorded as a
separate survey. Turtle sightings were classified based upon
Sightings data were collected on 2,115 snorkel and SCUBA
the sex of the turtle (Table 1). Data missing dates, sites or
dive surveys during the 2019-20 partnership year, totalling
durations were excluded from analysis. 5,264 turtle sightings
1,771.58 hours of survey effort. During each survey, the date,
(3,266 green and 1,998 hawksbill) from 2019-20 were
survey type (dive or snorkel), site, duration, environmental
analysed in this report.
conditions, and number of sightings (including zero sightings)
TURTLE RESCUE & REHABILITATION
© Abdulla Majeed
© Nicole PelletierPOPULATION RESEARCH
RESULTS
© Pip RoeNEW IDs
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153 new turtles (60 green and 93 hawksbill) were added to varied between months (Figure 4) and between site types
the Laamu ID database in 2019-20. Figure 2 illustrates recent (Figure 5).
growth in Laamu’s ID database. At the end of the 2019-20
Peaks in the number of new turtle identifications per hour
partnership year, the Laamu ID database comprised 527
were observed in May 2019, July 2019, September 2019 and
individual turtles (201 green and 326 hawksbill). The size of
January 2020 (Figure 4); the highest proportion of new turtle
Laamu’s ID database relative to databases in other atolls is
identifications were recorded at channel and outer reef sites
shown in Figure 3.
(Figure 5).
The number of new identifications per hour of survey effort
Figure 2: Total number of identified turtles in the Laamu ID database across differing years. To allow for comparison
with the 2018-19 and 2019-20 partnership years, data from preceding years were visualised to span the same
period (April - March).
Figure 3: Total number of identified turtles in 17 atolls in the Maldives.Azura, olive ridley ghost net amputee
TURTLE RESCUE & REHABILITATION
Figure 4: Number of new turtle identifications per hour across differing months of the 2019-20 partnership year.
y
Figure 5: Number of new turtle identifications per hour across differing site types during the 2019-20 partnership year.
SPECIES DISCOVERY CURVES
A species discovery curve is a visual representation of the Hithadhoo West and Olhuveli Reef appear to be approaching
cumulative number of individuals identified over time. Figures saturation for green turtles, however Hithadhoo Corner saw a
6 and 7 show discovery curves for green and hawksbill turtles spike in newly identified individuals in 2019.
from January 2016 to March 2020. The series do not start at
Hawksbill populations increased at a regular rate across sites.
zero as there were turtles identified from most reefs prior to
The known population at Kurethi increased sharply in 2017
2016. Discovery curves allow for detection of saturation - the
due to increased survey effort at this site. Kurethi’s hawksbill
point in time when you have photographed all animals at a
population also saw a spike in newly identified individuals in
site.
mid-2019.Azura, olive ridley ghost net amputee
TURTLE RESCUE & REHABILITATION
Figure 6: Discovery curve for green turtles in Laamu.
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Figure 7: Discovery curve for hawksbill turtles in Laamu.
POPULATION STRUCTURE
The structure of identified populations of green and hawksbill 8b). Juveniles cannot be sexed visually and cannot therefore
turtles in Laamu is visualised in Figure 8. Although the sex of be classified by sex.
newly identified turtles was recorded with relative
Channel corner and outer reef sites supported the greatest
consistency during the 2019-20 partnership year, the sex of a
proportions of adult individuals for both species (Figure 9).
high proportion of identified individuals remains unknown; a
Site types with fewer than ten identified individuals were
large proportion of identifications were recorded prior to the
excluded from analysis. A relatively high proportion of adult
incorporation of sex classification data.
green turtles were also identified at inner reef sites, and a
The green turtle population is dominated by adult individuals, notably greater proportion of male green turtles were
particularly adult females (Figure 8a). In contrast, the identified at outer reef sites (Figure 9a).
hawksbill turtle population comprises mostly juveniles (FigureFigure 8: Population demographics of identified a) green and b) hawksbill turtles in Laamu.
Figure 9: Population demographics of identified a) green and b) hawksbill turtles across differing site types.
CAPTURE-MARK-RECAPTURE
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Abundance curves were plotted based on the results from hawksbill turtles, respectively. Figure 12 shows abundance
RMark. Figures 10 and 11 show the abundance of green and per species at the atoll scale.
TURTLE RESCUE & REHABILITATION
Figure 10: Abundance curve for green turtles at three reefs in Laamu from May 2016 to November 2019.
Figure 11: Abundance curve for hawksbill turtles at four reefs in Laamu from May 2016 to November 2019.Azura, olive ridley ghost net amputee
Figure 12: Abundance curve for green and hawksbill turtles in Laamu (on an atoll scale) from May 2016 to November 2019.
Survival probability was assumed to be the same for all scale was 90.2% (Figure 15). For hawksbills apparent survival
animals in the population, regardless of whether or not the ranged from a low of 74.7% at Olhuveli Reef to a high of 89%
turtles were somewhere where they could be photographed. at Laamu Faru Haa (Figure 14). At the atoll scale, apparent
Apparent survival for green turtles ranged from a low 73.5% survival for hawksbills was 76.3%, lower than for green
at Olhuveli Reef to a high of 99.9% at Hithadhoo Corner turtles (Figure 15).
(Figure 13). Apparent survival for green turtles at the atoll
Figure 13: Apparent survival for green turtles at three reefs in Laamu between May 2016 and November 2019.Azura, olive ridley ghost net amputee
TURTLE RESCUE & REHABILITATION
Figure 14: Apparent survival for hawksbill turtles at four reefs in Laamu between May 2016 and November 2019.
Figure 15: Apparent survival for green and hawksbill turtles in Laamu (on an atoll scale) between May 2016 and November 2019.The long-term population growth rate (over 3.5 years) and the the most stable population. For hawksbill turtles, the pattern
coefficient of variation (CV) (a representation of the stability is similar: an increasing but unstable population at Hithadhoo
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of the population) are shown in Figures 16, 17, and 18 for West (Figure 17). At the atoll scale for the two species, long
green turtles, hawksbill turtles, and both species at the atoll term growth rates are very similar (within 1%), but hawksbill
scale, respectively. populations are slightly less stable than green populations
(Figure 18). Average annual growth rate was not plotted but
For green turtles, Hithadhoo West had the highest growth rate
was similar for both species (7.8% for greens and 7.1% for
but the highest CV, indicating instability in the population
hawksbills).
(Figure 16). Hithadhoo Corner has the lowest CV, indicating
TURTLE RESCUE & REHABILITATION
Figure 16: Long-term growth rate and coefficient of variation for green turtles at three reefs in Laamu
between May 2016 and November 2019.
Figure 17: Long-term growth rate and coefficient of variation for hawksbill turtles at four reefs in Laamu
between May 2016 and November 2019.Azura, olive ridley ghost net amputee
Figure 18: Long-term growth rate and coefficient of variation for green and hawksbill turtles in Laamu (on an
atoll scale) between May 2016 and November 2019.
y
© Abdulla Majeed
ENCOUNTERS PER HOUR BY SITE TYPE
During the 2019-20 partnership year, 1,088 encounter hawksbill turtles; a greater number of green turtle encounters
surveys were conducted, totalling 831 hours of survey effort. per hour were reported during most months throughout the
1,652 turtle encounters (1,119 green and 533 hawksbill) were 2019-20 partnership year (Figure 19). Green turtle
recorded during this period. For the purpose of analysis, a encounters per hour peaked in May 2019 (n = 1.89),
standardised unit of encounters per hour was used to remove September-November 2019 (n = 2.02-2.38), and January
the effect of variation in the number and duration of surveys. 2020 (n = 1.31) (Figure 19a). Hawksbill turtle encounters per
The number of encounters per hour varied between months hour remained relatively consistent throughout all months of
(Figure 19). the 2019-20 partnership year (Figure 19b).
Green turtles were encountered more frequently thanAzura, olive ridley ghost net amputee
Figure 19: Number of a) green turtle encounters per hour and b) hawksbill turtle encounters per hour across differing months
of the 2019-20 partnership year.
Higher proportions of surveys were conducted at channel Channel sites supported the greatest number of hawksbill
corner sites during May, September, October, November and turtle encounters per hour, closely followed by outer reef and
January (Figure 20); the greatest number of green turtle thila sites (Figure 21). Total monthly variation in hawksbill
encounters per hour were recorded at channel corner sites turtle encounters per hour (Figure 19b) is notably reflective of
(Figure 21). Total monthly variation in green turtle encounters monthly variation in the number of hawksbill turtle
per hour (Figure 19a) is noticeably reflective of monthly encounters per hour at outer reef and thila sites, however,
variation in the number of green turtle encounters per hour at appears less reflective of variation at channel sites (Figure
channel corner sites; channel corner sites exhibited the 23). Outer reef sites exhibited the greatest monthly variation
greatest monthly variation in the number of green turtle in the number of hawksbill turtle encounters per hour.
encounters per hour (Figure 22).Azura, olive ridley ghost net amputee
Figure 20: Proportion of encounter survey effort at different site types during the 2019-20 partnership year.
Figure 21: Number of green and hawksbill turtle encounters per hour across differing site types during the 2019-20
partnership year.Azura, olive ridley ghost net amputee
Figure 22: Number of green turtle encounters per hour at different site types across differing months of the 2019-20
partnership year.
Figure 23: Number of hawksbill turtle encounters per hour at different site types across differing months of the 2019-20
partnership year.SIGHTINGS PER HOUR BY SITE TYPE
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During the 2019-20 partnership year, 2,115 sightings surveys Green turtles were sighted more frequently than hawksbill
were conducted, totalling 1,771.58 hours of survey effort. turtles; a greater number of green turtle sightings per hour
5,264 turtle sightings (3,266 green and 1,998 hawksbill) were reported across almost all months during both the
were recorded during this period. For the purpose of analysis, 2019-20 and 2018-19 partnership years (Figure 24). Green
a standardised unit of sightings per hour was used to remove turtle sightings per hour peaked in May 2019 (n = 2.1),
the effect of variation in the number and duration of surveys. October-November 2019 (n = 2.74-2.6), and January 2020 (n
The number of sightings per hour varied between months = 2.44) (Figure 24a). Hawksbill turtle sightings per hour,
(Figure 24). Figure 24 also compares the number of sightings although lower than green turtle sightings per hour, remained
per hour between the 2019-20 and the 2018-19 partnership relatively consistent throughout all months of the 2019-20
years. and 2018-19 partnership years (Figure 24b).
TURTLE RESCUE & REHABILITATION
Figure 24: Number of a) green turtle sightings per hour and b) hawksbill turtle sightings per hour across differing
months of the 2019-20 and 2018-19 partnership years.Azura, olive ridley ghost net amputee
© Nicole Pelletier
Higher proportions of surveys were conducted at channel and 2018-19 partnership years. Channel corner and outer reef
corner and/or outer reef sites during May, October, November, sites exhibited the greatest monthly variation in the number
TURTLE RESCUE & REHABILITATION
and January (Figure 25). Channel corner and outer reef sites
consistently supported high numbers of sightings of green
of green turtle sightings per hour.
Hawksbill turtles were sighted with relatively similar
turtles (Figure 26). The greatest number of green turtle
frequency across most site types, however outer reef sites
sightings per hour, in both partnership years, were recorded
supported slightly higher numbers of sightings (Figure 26). A
at channel corner and outer reef sites. In 2019-20, the
notable proportion of the total monthly variation in hawksbill
number of green turtle sightings per hour were higher at
turtle sightings per hour (Figure 24b) is reflective of monthly
channel corner sites than in 2018-19, however the number of
variation in the number of hawksbill turtle sightings per hour
green turtle sightings per hour were lower at outer reef sites
at outer reef sites. This reflection is consistent in both the
in 2019-20 than in 2018-19. Much of the total monthly
2019-20 and 2018-19 partnership years (Figure 28). Outer
variation in green turtle sightings per hour (Figure 24a) is
reef sites exhibited the greatest monthly variation in the
reflective of monthly variation in the number of green turtle
number of hawksbill turtle sightings per hour.
sightings per hour at channel corner and outer reef sites
(Figure 27). This reflection is consistent in both the 2019-20
Figure 25: Proportion of sightings survey effort at different site types during the 2019-20 partnership year.Azura, olive ridley ghost net amputee
Figure 26: Number of green and hawksbill turtle sightings per hour across differing site types during the a) 2018-19 and b) 2019-20
partnership years.
Figure 27: Number of green turtle sightings per hour at different site types across differing months of the a) 2018-19 and b)
2019-20 partnership years.
Figure 28: Number of hawksbill turtle sightings per hour at different site types across differing months of the a) 2018-19 and b)
2019-20 partnership years.POPULATION RESEARCH
DISCUSSION
© Tiana WuCAPTURE-MARK-RECAPTURE
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Reliable abundance information is critical for the but also a high CV, indicating that there is high recruitment,
conservation and management of species at risk. Assessments but turtles may not be staying on the reef. The population at
of population abundance, trends and distribution are this site is less stable than at Hithadhoo Corner. The green
necessary to inform conservation actions. Estimates of turtle population at Olhuveli Reef is slowest growing. The CV
abundance also allow for quick detection of population is relatively high while apparent survival is the lowest of the
declines and management interventions. three sites studied. This could indicate that the carrying
capacity of the reef (saturation) has been reached, however
The abundance graphs based on the CMR analyses show
could also suggest disturbance, which warrants further
populations swings between the monsoon seasons; however,
investigation.
this is more visible in the hawksbill data. These population
swings are particularly prevalent at Hithadhoo Corner and The hawksbill population at Hithadhoo West has the highest
Olhuveli Reef but were also observed at Hithadhoo West. The average annual growth rate but is by far the least stable (high
pattern of higher populations during the north-east monsoon CV). This is likely due to the increased effort at this site over
season and lower populations during the south-west monsoon the past year. The population at Olhuveli Reef has lowest
season repeats in the 2017, 2018 and 2019 hawksbill data. A long-term growth rate and the lowest apparent survival.
similar but less obvious pattern is visible in the green turtle Similar to the green turtle data, this could indicate that the
data for Hithadhoo West and Hithadhoo Corner but not at turtles are leaving the reef due to disturbance or that
Olhuveli Reef. The north-east monsoon is high season for saturation of individuals has been reached. Laama Faru Haa
tourism in the Maldives and the clear, calm waters during this has the highest apparent survival of the four sites studied.
season make turtles easier to spot. This may explain the
At the atoll scale, apparent survival and average annual
patterns observed, however further research is needed to
growth rate are higher for green turtles; however, long term
accurately infer population trends.
growth rate is 1% higher for hawksbill turtles. The CV is
The green turtle population at Hithadhoo West has gone up lower for green turtles indicating a slightly more stable
and down over the last few years. A similar but less drastic population. Populations of both species have increased on
pattern can be seen at Hithadhoo Corner. Survival at average over time but there have been decreases in the past,
Hithadhoo Corner is 99.9% and it has the most stable most notably in November 2018, which coincides with the
population. Hithadhoo West has a high long-term growth rate transition between two turtle biologists at Six Senses Laamu.
© Abdulla MajeedENCOUNTERS AND SIGHTINGS PER HOUR BY SITE TYPE
Monthly variation in the number of green turtle encounters occupancy. In 2019-20, there were peaks in resort occupancy
per hour notably reflected monthly variation in the proportion in August 2019 (5,719 guest nights) and December 2019
of surveys conducted at channel corner sites. Channel corner (5,234 guest nights). These peaks coincided with troughs in
sites supported high numbers of green turtle encounters and both encounters per hour and sightings per hour. For most
exhibited the greatest monthly variation in the number of surveys - with the exception of research dives - the collection
green turtle encounters per hour. Similar observations were of encounter and sightings data was secondary to
noted with sightings data in both the 2018-19 and 2019-20 guest-related responsibilities. As such, it is possible that,
partnership years; the number of green turtle sightings per during times of high resort occupancy, the collection of
hour was notably influenced by the proportion of surveys encounter and sightings data was less consistent, resulting in
conducted at channel corner and outer reef sites. Channel an overall decline in the numbers of encounters and sightings
corner and outer reef sites expressed the greatest monthly per hour.
variation in the number of green turtle sightings per hour.
Data analysis in this report highlighted significant monthly
Monthly variation in the number of hawksbill turtle variation in the number of encounters per hour, and the
encounters per hour notably reflected monthly variation in number of sightings per hour, at channel corner and outer
the proportion of surveys conducted at outer reef and thila reef sites. Channel corner and outer reef sites are located on
sites. Outer reef and thila sites supported high numbers of the outer edges of the atoll and could represent important
hawksbill turtle encounters, and outer reef sites exhibited the sites for migrating turtles. Monthly variation in the number of
greatest monthly variation in the number of hawksbill turtle encounters and sightings at channel corner and outer reef
encounters per hour. As with green turtles, similar sites could be explained by the frequent, yet unpredictable,
observations were noted with sightings data in both appearance and disappearance of transient individuals. These
partnership years; the number of hawksbill turtle sightings turtles may utilise these sites to clean, forage or rest, en
per hour was notably influenced by the proportion of surveys route to foraging or nesting sites elsewhere. The relative
conducted at outer reef sites. Outer reef sites expressed the consistency of encounters and sightings at other site types
greatest monthly variation in the number of hawksbill turtle could be indicative of more stable, resident turtle populations.
sightings per hour.
Monthly variation in the number of encounters and sightings
Monthly variation in the number of encounters and sightings at channel corner and outer reef sites could also be explained
per hour may have also been influenced by variation in resort by seasonal shifts in population size. Despite little similarity
© Maeesha Muhammadin monthly variation in sightings per hour between therefore reflect the true relative population size at different
partnership years to suggest a strong seasonal trend, channel sites. However, as survey effort was notably lower for
corner and outer reef sites could exhibit seasonal changes in encounter data than for sightings data, it is equally possible
population size. Increased survey effort over multiple years is that encounter data for site types with particularly low survey
required to accurately determine seasonal influence. effort were disproportionately influenced by surveys with
unusual numbers of encounters. Consequently, encounter data
Observations from encounter and sightings data were often
may not reflect the true relative population size at different
similar - highlighting the potential usefulness of sightings
sites either. Increased encounter survey effort over multiple
data for population research - however there were
years is required to accurately infer the relative importance
discrepancies between the two methods. Sightings data were
of site type for sea turtle populations.
likely influenced by repeat sightings of the same individual
turtles during the same survey; sightings data would not likely
© Nicole Pelletier
PRIORITY SURVEY SITES
The relationship between the number of sightings and the identified as priority survey areas for the 2020-21
number of encounters at a site can be used to identify areas partnership year.
requiring greater investment of encounter survey effort. High
Blue Lagoon, Fonadhoo Outside, Gaadhoo Corner, Gaadhoo
numbers of sightings, low numbers of encounters and low
Inside, Gaadhoo Outside, Kunahandhoo Inside, Kurethi,
survey effort, suggest a high proportion of unidentified
Maavah Kandu, Mundoo Kandu, Olhuveli Corner, Pink Thila and
individuals. A ratio of the number of encounters to the
Raa Dashu Haa were identified as priority survey sites for
number of sightings was calculated for 24 sites for green
green turtles.
turtles and 21 sites for hawksbill turtles. These ratios are
visualised alongside survey effort data in Figure 29 (green Blue Lagoon, Fares Outside, Gaadhoo Corner, Gaadhoo Inside,
turtles) and Figure 30 (hawksbill turtles). Sites with low ratios Gaadhoo Outside, Haleema Haa and Maavah Kandu were
of encounters to sightings and low survey effort were identified as priority survey sites for hawksbill turtles.Figure 29: Map of Laamu illustrating the ratio of green turtle encounters to green turtle sightings at 24 sites (highlighted in blue in the key). Proportional circles represent survey effort. Additional sites with insufficient sightings and/or encounters to calculate ratios are visualised without the associated proportional circles.
Figure 30: Map of Laamu illustrating the ratio of hawksbill turtle encounters to hawksbill turtle sightings at 21 sites (highlighted in blue in the key). Proportional circles represent survey effort. Additional sites with insufficient sightings and/or encounters to calculate ratios are visualised without the associated proportional circles.
NESTING, ENTANGLED/INJURED TURTLES AND
GHOST NET RESEARCHNESTING
The 2019-20 partnership year spanned two distinct nesting ongoing. Further information about Olive Ridley Project’s
seasons at Six Senses Laamu. 24 nests were laid during the nesting research in 2019 can be found in our Nesting in
2019 nesting season and the 2020 nesting season remains Laamu Technical Report 2018 & 2019.
© Shelley Turnbull
ENTANGLED/INJURED TURTLES AND GHOST NETS © Andy Ball
Three entangled/injured turtles and five ghost nets were green turtles were able to be released immediately, however
reported during the 2019-20 partnership year, fewer than the olive ridley turtle - named Elba by resort guests - was
were reported during the 2018-19 partnership year (Figure transferred to ORPs Marine Turtle Rescue Centre based at
31). Nationwide, 142 turtles were reported entangled in Coco Palm Dhuni Kolhu, Baa atoll. Elba underwent surgery to
2019-20, down from 177 the previous year. 69 nets were remove a section of ghost net from her throat; she made a full
recovered in the Maldives in 2019-20, down from 94 the recovery and was released a few months later.
previous year. Despite the decrease in reported
Data were collected from each of the five ghost nets to input
entanglements and ghost nets in Laamu aligning with national
into ORPs ghost net database. This database enables ORP to
trends, the number of reported incidences likely remains a
determine the origin of ghost nets and to identify the specific
gross underrepresentation of the true number of
net types most likely to entangle turtles (for more
entanglements and ghost nets.
information see Stelfox et al. 2019; 2020). This information
Three different species were found entangled or injured - one helps ORP to develop targeted initiatives to reduce loss of
hawksbill, one olive ridley and one green. The hawksbill and fishing gear.Figure 31: Incidences of entangled/injured turtles and ghost nets reported during the 2018-19 and 2019-20 partnership years.
EDUCATION AND OUTREACH
COMMUNITY
Community engagement is vital for effective conservation and protection of entire ecosystems. The festival was rebranded
is a key priority for ORP. ORP participated in a number of Laamafaru Festival. ORP was heavily involved in the planning
community outreach and education activities during the of the festival and hosted an interactive stall in the seagrass
2019-20 partnership year. section. ORP partners Fourth Element kindly donated prizes
for activities at the festival. In 2019, Laamafaru festival drew
In April 2019, ORP helped deliver a module to 56 students
an audience of more than 1,500.
from three schools in L. Gan for the resorts “Hello Hallu”
educational programme. The module detailed the importance In February 2020, ORP helped to organise a community event
of seagrass and mangrove habitats and explored the to celebrate International Women and Girl’s in Science Day.
interconnectedness of marine ecosystems. The module The event highlighted the value of citizen science in marine
focussed heavily on the importance of seagrass meadows for conservation and was attended by 25 women and girls from
green turtles and incorporated an interactive game which the local community. ORP hosted informal, interactive
explored the impact of seagrass removal on green turtle sessions on photo identification and demonstrated how to
populations. Following the classroom session, ORP safely disentangle a turtle from ghost net.
accompanied the students on a field trip to a local mangrove.
ORP also participated in beach and reef clean events and
ORP will continue to co-teach the module for more schools in
assisted with several marine-themed community movie
the 2020-21 partnership year.
nights. ORP attended quarterly Eku Ekee meetings - which
In 2019, expanding on the success of Laamu Turtle Festival in bring together key stakeholders within the local community -
previous years, the Maldives Underwater Initiative (MUI) throughout the 2019-20 partnership year.
broadened the scope of the annual festival to advocate the
© Leanna Crowley
© Tiana Wu
© Leanna Crowley© Leanna Crowley
GUESTS
Olive Ridley Project conducted activities to interact and most likely the result of increased interactions at nest
engage with guests at Six Senses Laamu throughout the hatching events during peak hatching season.
2019-20 partnership year.
ORP conducted a wide variety of guest activities throughout
The number of guest interactions - a measure of attendance the 2019-20 partnership year. Hatching events accounted for
at ORP events - varied between months (Figure 32), however the greatest proportion of guest interactions, closely followed
appeared to mirror variation in resort occupancy; greater by turtle house reef snorkels (Figure 33). Guest activities
numbers of guest interactions were recorded during periods conducted on an occasional basis accounted for the smallest
of high occupancy. The number of guest interactions relative proportion of guest interactions. For reference, brief
to the total number of guests would likely show greater descriptions of the activities conducted can be found in Table
consistency between months. The number of guest 2.
interactions peaked between July and October 2019. This was
Figure 32: Number of guest interactions across differing months of the 2019-20 partnership year. Resort occupancy is
illustrated by the number of guest nights per month. Darker bars represent months during which ORP staff were off
island for extended periods of time.Figure 33: Proportion of guest interactions at different guest activities.
Table 2: Activities conducted by ORP at Six Senses Laamu.
Nest hatching event ORP supervised nest hatching event. Detailed briefings on nest hatching protocol were conducted before hatchlings
were released to run to the ocean. Strict guidelines applied to this guest activity to ensure the welfare of the turtle
hatchlings.
Turtle HR snorkel Weekly guided snorkel at Olhuveli Reef (Six Senses House Reef). Detailed turtle-specific briefings, including ORPs
snorkelling code of conduct, were provided before guests entered the water. Guests were later emailed with
information about the turtles sighted during the snorkel.
Welcome reception Weekly 1.5-hour - 4-hour shifts manning the MUI information desk in the welcome reception at Six Senses Laamu.
Other Miscellaneous guest interactions, predominantly informal interactions with guests around the island during the day or
during Nestwatch shifts. Junior Marine Biology (JMB) sessions were also included in this classification. ORP developed
and delivered practical photo identification workshops to Junior Marine Biologists choosing to complete their personal
project module on turtles. JMB sessions will be classified separately in future partnership years.
Presentation Weekly evening presentation at Six Senses Laamu’s ice cream parlour (ICE). Presentations on general turtle biology
and specific ORP research were delivered on rotation.
GM cocktails Monthly attendance at the General Manager’s cocktail party. ORP engaged informally with guests to promote
ORP/MUIs guest activities.
Kids Club Weekly turtle educational sessions at Six Senses Laamu’s Kids Club. Activities ranged from colouring to photo
identification.
ICE Monthly drop-in sessions at Six Senses Laamu’s ice cream parlour (ICE). ORP engaged informally with guests, running
mini workshops on photo identification and ghost net bracelets to illustrate ORPs research.Nest excavation (occasional) Occasional walkthrough of nest excavations for interested guests/Junior Marine Biologists. ORP demonstrated the
excavation process and explained the value of data collected.
Dolphin cruise (occasional) Occasional guided sunset dolphin cruise. ORP provided information on the dolphin species commonly sighted in Laamu
and ORP/MUIs guest activities.
Snorkel boat (occasional) Occasional guided snorkel excursion. Detailed turtle-specific briefings were provided before guests entered the water.
Guests were later emailed with information about the turtles sighted during the snorkel.
Guest dive (occasional) Occasional guest dive. ORP engaged informally with guests about ORPs research and, if requested, provided detailed
turtle-specific briefings before guests entered the water. Guests were later emailed with information about the turtles
sighted during the dive.
ORP coordinated one-off guest events throughout the year to presentation and shared information about the newly
mark special occasions. In May 2019, ORP conducted identified individual. Guests were then asked to submit names
activities to mark World Turtle Day. ORP hosted a turtle house for the new turtle. At the end of the evening, a lucky draw was
TURTLE RESCUE & REHABILITATION
reef snorkel, ran a ghost net bracelet workshop, and manned held to announce the winner. The winning guest was
a “turtley-special” photo booth. ORP also coordinated with presented with a turtle naming certificate to take home.
Six Senses Laamu’s F&B team to arrange the delivery of turtle
ORP was involved in a number of additional one-off guest
shaped cookies to guest villas to celebrate the occasion.
events throughout the partnership year. These included an
In January 2020, ORP hosted a naming event at the General under-the-sea themed cocktail party with MUI, a turtle
Manager’s cocktail party to celebrate identifying Laamu’s skeleton treasure hunt with Kids Club, Earth Day, Women’s
500th turtle. During the event, ORP delivered a short Dive Day and World Seagrass Day.
© Leanna CrowleyHOSTS Olive Ridley Project remains immensely grateful for Six This year, ORP conducted training sessions with the launch Senses Laamu’s support, and delights in the opportunity to and watersports teams to demonstrate our entangled turtle give back, share knowledge, and involve hosts in our research. protocol. ORP also refreshed turtle nesting and hatching Throughout the 2019-20 partnership year, ORP presented at training with the security team and trained and coordinated new host orientation sessions. Here, we explained our the resort’s Nestwatch team. Further information about the research and provided new hosts with opportunities to Nestwatch team and ORPs nesting research can be found in participate. During one orientation session, ORP led an our Nesting in Laamu Technical Report 2018 & 2019. excursion to Gaadhoo to involve hosts in our nesting research.
FUTURE DIRECTION
FUTURE DIRECTION
1. Expand photo ID data collection and
increase community activities
Following the relaxation of COVID-19 restrictions on dive and
snorkel surveys, ORP will increase survey effort and expand
data collection. To further increase awareness and
engagement within the community, ORP will develop
informational sessions on turtle egg and meat consumption to
deliver to local schools once inter-island travel resumes.
2. Nesting research programme on Gaadhoo
ORP will work alongside the Environmental Protection Agency
(EPA) and other stakeholders to establish a nesting research
programme on Gaadhoo. This will facilitate increased data
collection and help increase our understanding of nesting
turtle populations in Laamu.
3. Continued improvements to Six Senses
Laamu’s Nestwatch programme and guest
hatching experiences
Six Senses Laamu’s Nestwatch programme will be further
streamlined to include remote monitoring techniques, and
guest hatching experiences will continue to improve with the
addition of continuous barriers to the water.REFERENCES
Azura, olive ridley ghost net amputee
Chaloupka, M.Y. and Limpus, C.J. (1997). Robust statistical modelling of hawksbill sea turtle growth rates (southern Great
Barrier Reef). Marine Ecology Progress Series. 146, 1-8.
Hudgins, J., Mancini, A, and Ali, K. (2017). Marine turtles of the Maldives - A Field Identification Guide. Gland, Switzerland: IUCN
and Government of Maldives. 90.
Kendall, W.L. and Pollock, K.H. (1992). The robust design in capture-recapture studies: a review and evaluation by Monte Carlo
simulation. Wildlife 2001: Populations. Elesvier, London, UK. 31-43.
Laake, J.L. (2013). RMark: An R Interface for Analysis of Capture-Mark-Recapture Data with MARK. AFSC Processed Rep,
NOAA. Seattle, Washington, USA. 2013-01, 25.
Limpus, C. and Chaloupka, M. (1997). Nonparametric regression modelling of green sea turtle growth rates (southern Great
Barrier Reef). Marine Ecology Progress Series. 149, 23-34.
Otis, D., Burnham, K.P., White, G.C. and Anderson, D.R. (1978). Statistical inference from capture data on closed animal
TURTLE RESCUE & REHABILITATION
populations. Wildlife Monograms. 62, 1-135.
Stelfox, M., Bulling, M. & Sweet, M. (2019). Untangling the origin of ghost gear within the Maldivian archipelago and its impact
on olive ridley (Lepidochelys olivacea) populations. Endangered Species Research. 40, 309-320.
Stelfox, M., Lett, C., Reid, G., Souch, G. & Sweet, M. (2020). Minimum drift times infer trajectories of ghost nets found in the
Maldives. Marine Pollution Bulletin. 154, 111037.
© Leanna Crowley
Back cover photo: © Six Senses LaamuOlive Ridley Project expresses its sincere appreciation for its partnership with Six Senses Laamu.
Without their support, this work would not have been possible. Olive Ridley Project look forward to to
a continued and successful partnership with Six Senses Laamu.
Olive Ridley Project are willing to share data collected as part of this study.
Please contact martin@oliveridleyproject.org for details.
The information and ideas in this report are the intellectual property of The Olive Ridley Project. Any scientific data distributed to collaborators and partners remain property of
Olive Ridley Project and are not to be shared with a third party without prior permission. All images, unless otherwise stated, are credited to Olive Ridley Project.You can also read
