Download Marine turtles and Boats in the Galápagos

Marine turtles and Boats in the Galápagos:
recommendations for a boat traffic management plan at
San Cristóbal Island.
Independent Project EV5914-EV5915
Daniela Alarcón
Student ID: 12723037
James Cook University Master of Science
Supervisor: Mark Hamann
February 17, 2015
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
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ABSTRACT
The growing demand for tourism opportunities and an increasing human population in
the Galápagos Islands has led to increased boat traffic around the islands. Key species and
ecosystems are under threat from boating and will likely continue to be affected, due to the
manner in which these types of activities are handled, especially in the shallow bays close to
inhabited islands. Therefore, it is essential to promote a zoning plan that allows a better
understanding of how to manage boat use and ecosystem impacts in certain areas of the
archipelago, particularly in the most visited parts.
Doing so will ensure improved
conservation of this pristine environment.
The aims of this study were to identify the regions for possible interactions between sea
turtles and boat traffic in the bays close to the populated area of San Cristóbal IslandGalápagos and to contribute to the development of a boat traffic management plan that
could be applied to the zoning of the Marine Reserve. The principal objectives of this effort
will contribute to the scientific assessment of the movement, site fidelity and habitat use of
sea turtles on the shallow bays of San Cristóbal Island, to categorise the most susceptible
areas of sea turtle interactions with vessels and speedboats around the touristic places on the
archipelago, and to generate boat traffic management recommendations.
Pictures exposing Green sea turtles boat strikes cases registered in this study
Conclusively, we expect to give scientific information to the decision makers on the
Galápagos, to aid them in implementing a management strategy to be included in the zoning
plan of the Galápagos Marine Reserve (GMR). We also aim to create awareness in the local
community about the importance of compliance of these zoning plans in order to conserve
the species and ecosystems on the islands.
Key words: Marine turtles, vessel traffic, human activities, tourism, and zoning,
Galápagos, Ecuador.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
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ABSTRACT
2
INTRODUCTION
6
AIMS AND OBJECTIVES
7
Expected outcomes:
7
Significance of the study:
7
LITERATURE REVIEW
8
Marine Protected Areas
8
Sea turtle conservation
9
Management plans and zoning
10
Boats and threatened marine life
11
Marine turtles and boat strikes
12
The Galápagos Islands
14
Oceanographic conditions around Galápagos
15
The Galapagos National Park and Marine Reserve
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Actual Zoning Plan
16
Boats and tourism in Galápagos
17
Marine Turtles in the Galápagos
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METHODS
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Study Area
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Figure 1. San Cristóbal Island and the main study sites close to the inhabitant area
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Data Compilation
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Boat Surveys/ Census
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Captured and Tagged Individuals
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Satellite Tracking
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Acoustic Tracking
21
Boat Tracks and Boat Traffic
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Data Analysis
22
Data Pre-processing
22
Spatial Analysis
23
Alpha Hull Estimation (AH)
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GIS Analysis
23
Determining the Risk of Boat Strike
23
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
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RESULTS
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Surveys and Census – Population Demographics
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Figure 2: Turtle population demographic results estimated in the study area.
24
Figure 3: Census of C. mydas and E. imbricata, using the Shark fishing method in the three
different study sites.
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Figure 4. Kernel density indicating where there is greater density of sightings during censuses
in transects parallel to the coast.
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Captured and Tagged Individuals
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Table 1. Mean, standard deviation, and range of morphometric measurements taken at each
study site (cm).*n is the sample size of turtle. The weight is expressed in kg.
27
Figure 5. Captures, re-captures and individuals that present any type of boat strike of C.
mydas and E. imbricata in the study area.
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Boat Strike Incidence
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Site fidelity
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Figure 6. Photo-ID methodology in order to identify site fidelity to certain areas in identified
individuals.
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Satellite and acoustic tracking
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Table 2. Summary of satellite and acoustic tracked individuals
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Figure 7. Habitat preference of the three E. imbricata satellite tagged individuals Zones with
intense colours represent areas of greatest use.
30
Figure 8. Habitat preference of the four male C mydas followed by acoustic telemetry. Zones
with intense colours represent areas of greatest use.
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Figure 9. Habitat preference of a female C. mydas and a male of C. mydas followed by
acoustic telemetry. Zones with intense colours represent areas of greatest use.
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Figure 10. Habitat preference of two E. imbricata followed by acoustic telemetry. Zones with
intense colours represent areas of greatest use.
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Core Areas
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Figure 11. Home range (Alpha hull 60) for E. imbricata.
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Figure 12. Home range (Alpha hull 60) for C. mydas
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Boat Tracks and Boat Traffic
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Figure 13. Number of vessels registered during the dates of continuous monitoring
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Figure 14. Average speed registered according to each vessel sighted.
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Figure 15.Map showing the trajectories of tourism, fisheries and transport vessels in San
Cristobal Island recorded in this study. Each yellow line is a different boat.
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Figure 16. Map showing the trajectories of tourism, fisheries and transport vessels in
Galápagos Island recorded in this study. Each yellow line is a different boat.
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Figure 17.Habitat use of C.mydas and E. imbricata overlapped with the main vessels routes
(tourism, fishing and transport) operating from San Cristobal Island.
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Determining the Risk of Boat Strike
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Figure 18. Probability of vessel strikes (tourism, fishing and transport) with sea turtles in San
Cristobal Island. Areas with the highest colour are the most prone to this type of
anthropogenic impact areas.
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Figure 19. Probability of vessel strikes (tourism, fishing and transport) with sea turtles in the
Galapagos Islands. Areas with the highest colour are the most prone to this type of
anthropogenic impact areas.
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DISCUSSION
Census and direct observations of sea turtles in aquatic habitats (Demography and
population status)
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Captured and tagged individuals. External markings INCONEL ® type # 681 and photo
identification.
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Boat Strike Incidence
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Acoustic Monitoring
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Core Areas
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Site Fidelity
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Determining the Risk of Boat Strikes
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Conclusions and Recommendations
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Recommendations for a Boat Management Plan
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Goal:
44
Strategies:
44
Recommendations:
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ACKNOWLEDGMENTS
45
REFERENCES
46
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INTRODUCTION
In general sea turtle research, both in the Galápagos (Green 1978; Green D and F
Ortiz-Crespo 1981; Green 1984; Zarate and Dutton 2002; Seminoff et al. 2007; Seminoff
and Zarate 2008) and other parts of the world have focused on nesting sites (Hamann et al.
2006). Direct observations in aquatic habitats are less common (Fuentes et al. 2010);
therefore most of the research has been focused on sea turtle nesting beach efforts (Hamann
et al. 2010). Consequently, the information that exists about the ecology and biology of this
group of animals is generally for adult females (Bjorndal 1995; Hamann et al. 2010).
Furthermore, considering that this group of animals lives nearly 90% of its life
underwater (Meylan and Meylan 1999; Meylan and Meylan 2011); there is an urgent need
to maintain and establish long-term studies that consider all stages of their life cycle,
especially its coastal marine habitats (Gaos et al. 2012). In this aspect, the collection of insitu data is the minimum information required in order to make decisions for management
and protection.
Also necessary for decision-making is information about principal
distribution, population, and habitat use and life range; especially in areas of human
presence.
Recently, San Cristobal Island was identified as a critical area for foraging,
development and resting for green turtles and hawksbill turtles (Muñoz et al. 2015 in prep).
However, it has also has been identified that populations living close to the inhabited areas
are threatened, principally by the speed boats operating in the area.
In this context, it is crucial to continue gathering information due to these species local
and global significance in developing management and protection. Contribution to
understanding the ecology of green and hawksbill turtles is essential, as is combining this
information with appropriate human action. Likewise, a crucial part of the population of the
eastern Pacific to the above two species depends on the nesting and feeding areas found in
Galápagos. Consequently, the Ecuadorian government requires continuous, timely and
reliable information in order to protect and manage these populations.
This study seeks to provide current information that will be the basis for a long-term
research project on the aggregations of marine turtles in coastal areas of the Galapagos. As a
result, it is expected to provide adequate and timely conservation strategies.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
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AIMS AND OBJECTIVES
The growing demand for tourism opportunities and an increasing human population in
the Galapagos Islands has led to increased boat traffic around the islands. Key species and
ecosystems are under threat from boating and will likely continue to be affected, especially
in the shallow bays close to the main islands. Therefore, it is essential to promote a zoning
plan that allows a better understanding of how to manage boat use and ecosystem impacts
in certain areas of the archipelago, particularly in the inhabited and most visited parts. Doing
so will help ensure an improved conservation of this pristine environment.
The aim of this study is to identify the regions for possible interactions between sea
turtles and boat traffic in the bays close to the populated area of San Cristobal and to
contribute to the development of a boat traffic management plan that could be applied
within the Marine Reserve zoning.
The principal objectives of this effort are to:
Contribute to the scientific literature about the movement, site fidelity and habitat
use of sea turtles on the shallows bays of San Cristobal Island.
• Categorise the most susceptible areas of sea turtle interactions with vessels and
speedboats around the touristic places on the archipelago.
• Generate recommendations for a boat traffic management plan.
•
Expected outcomes:
Provide scientific information to the decision makers on the Galapagos, to aid them
implement a management strategy within the zoning plan of the GMR.
• Create awareness in the local community about the importance of compliance to
these zoning plans in order to conserve the species and ecosystems on the islands.
•
Significance of the study:
There are four species of sea turtles reported in the Galapagos Islands, all of them listed
as endangered (Chelonia mydas, Lepidochelys olivacea), or critically endangered
(Dermochelys coriacea, Eretmochelys imbricata) (Blundell 2002; IUCN 2014). The
Galapagos archipelago is regarded as one of the most important areas in the Eastern Pacific
for nesting, foraging and breeding grounds for the Green turtle (C. mydas) (Green and OrtizCrespo 1982; Green 1984; Zarate et al. 2002; Seminoff et al. 2008), and most recently a
foraging ground but still unknown for the Hawksbill turtle (E. imbricata) (Munoz et al. 2014
in progress).
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Marine reserves all around the word provide relief from some of the anthropogenic
impacts to marine species (Allison et al. 1998, Roberts et al. 2005). This affords a protection
for sea turtles by regulating the fishing pressure and providing a safe and healthy
environment. However, even though the GMR promotes a management plan included in the
Galapagos National Park administration since 1998, maintaining a zoning plan based in
different activities allowed in each area. Low concern has been applied to emerging threats
such as the impacts of transport and boat activities on the ecosystems and wildlife mainly
with sea turtles.
In recent years, a lack of effective protection and a growing risk in some areas have
been seen in the Galapagos, especially involving the increased boat traffic, due to the
intensification of tourism, which affects the populations of marine turtles on the archipelago
(Carrion and Zarate 2007; Denkinger et al. 2013). The material presented in this study seeks
to provide information that can be used to improve the efficiency of the management plan
for those areas and generate regulations for maritime traffic on the islands towards
minimising their impacts on wildlife.
LITERATURE REVIEW
Marine Protected Areas
Marine Protected Areas (MPA’s) cover a wide range of places designated for ecosystem
preservation, protection of species and management of marine resources from small marine
parks, which serve to the protection of species or specific resources, to large areas seeking to
achieve a range of economic, social and environmental protection objectives, including
different levels of restrictions (Agardy 1999; Agardy et al. 2003). According to the UICN, it is
clearly defined, recognized, dedicated and managed spaces, which through legal or other
effective actions promote to achieve long-term conservation of nature and its associated
ecosystem services and cultural values.
Also posed different categories of protection according to the type of management and
permitted activities within the protected area (UICN 2014). It is well established in some
areas that MPAs as conservation strategies are an effective way of managing natural
resources and behaviour of people who depend on them (Allison et al. 1998; Pomeroy et al.
2005). The type of actions developed in a protected area and the effective appliance of the
management plans will lead to an effective use of resources (Swartz et al. 2010).
In recent years, following from examples in terrestrial protected areas, MPAs have
turned to a more holistic approach, based in a social ecological system, resulting in
multiple-use reserves that try to accommodate many different user groups and stakeholders,
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each with its own needs and objectives (Cumming 2011). This holistic approach is assisting
a wide variety of functions through countless cases and regulations that employs new models
and tools to reach ecological sustainability (Davis y Tysdell 1995). Administrators had
discovered that a diversity in the uses indeed be fostered without adverse impacts on
ecosystem function, which has encouraged the creation of more MPA around the world.
While there are large protected areas, relatively well managed, as it is the case of the
Great Barrier Reef Marine Park (GBRMP) and the Galapagos National Park (GNP), there are
many examples of MPAs that have zoning plans for various types of extraction of resources
and recreational activities in which compliance is poor and the benefits of zoning are
unknown. Around the world there are several “paper park” protected areas, where
delimitation areas and goals consist only in management plans, poorly defined in breach of
its purpose of management and protection (Halpern 2003; Claudet et al. 2008).
According to Kelleher 1995, only 9% of the MPAs have management that complies
with the management objectives for that specific area. Although the human element in
marine protected areas should not be understated, it is important to maintain no-take areas
that provide complete protection for the objectives settled in each area. The success of any
protected area is closely related to how well user groups and stakeholders are identified and
brought into the planning and management processes through clearly defined delimitations
and management plans (Agardy 1999; Sumaila et al. 2000; Sanchirico 2006).
Sea turtle conservation
The life cycle of sea turtles is highly complex, exhibiting slow growth and late sexual
maturity leading to a pattern of longevity coupled with the intrinsic characteristics of their
life history. This allows turtles to spend decades in different habitats using and modifying the
medium (Chaloupka et al. 2010).
An alternation has been found in habitats between nesting beaches, breeding grounds,
feeding and development areas, in both neritic and oceanic areas. Mating is carried out at
sea in the vicinity of tropical beaches; females come to nest at night in the same beach
where they were born (Bjorndal et al.1983). Hatchlings emerge roughly between 45 and 60
days after and head to the ocean. The sex of sea turtles is dependent on the temperature
affecting the nest during the middle third of the incubation process (McClenachan et al.
2006).
After the event called "natatorium frenzy" subsequent to hatching, the juvenile phase of
the life cycle of the turtles begins. This period will distinguish itself into two sub-phases,
oceanic (feeding habitat of small juveniles) and coastal (habitat development of advanced
juveniles). Neonates begin an oceanic pelagic stage that float in association with Sargassum
or tide lines that form near the fronts of the mainstream (Carr 1987) feeding on the available
resources. Upon reaching the size of curved carapace length (CCL) between 30 and 40 cm,
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the juveniles recruit neritic habitats. There, shallow waters rich in seaweed, marine grasses or
corals are predominant (Balazs 1984; Bjorndal and Bolten 1988). In this stage, turtles modify
their diet to a more specialised type of resources (Mortimer 1982). Sea turtles are highly
migratory and may travel long distances. They move between feeding and breeding areas,
which can be separated by several hundred kilometres and where they can stay for several
years (Limpus et al. 1992).
Sea turtles have been present in the marine and coastal ecosystems for over 100
million years; families that include the current seven species of sea turtles date from the
Cretaceous period (Limpus and Fien 2009). However, after the second half of the twentieth
century these species have suffered a significant decline in population. Currently, the
different species of sea turtles are listed as endangered critically, endangered or vulnerable
by the International Union for Conservation of Nature and Natural Resources (IUCN 2014).
Turtles are subjected to high natural mortality at all stages of their early life cycle; this
mortality is compensated by a high reproductive rate (Hirth 1980). However, natural hazards
affecting these reptiles are joined directly or indirectly by anthropogenic impacts, causing
major decreases in their populations. The main threat to sea turtles is the overexploitation
with direct or incidental catches by the various fisheries, or directly in the nesting beaches.
In several countries turtles are seen as valuable food or trade resources, particularly for small
communities (Wilson and Tisdell 2001).
Historically there has been an attempt to improve studies related to reproductive
biology and nesting beach protection regarding investigations of their ecology and habitat
use. Fortunately in recent years, work on foraging areas has been prioritised. These studies
will help to clarify their role as predators and as conduits of energy flows and nutrients
within and between ecosystems (Bjorndal 2000; Leon and Bjorndal 2002).
Management plans and zoning
Every protected area or park needs a plan that describes how the activities that take
place within the area should be managed. This plan represents the future desired state or
condition for the MPA and the most effective and fair way to achieve it. Trying to maximise
the benefits of the protected area and minimising costs, the application of policies is an
important component of the overall document, sometimes called management plan.
In order to achieve effectiveness in these management plans, continuous feedback of
what is happening in the MPA is required (Pomeroy et al. 2005). It is necessary to develop a
set of indicators involving managers, planners and other stakeholders and enhance the
potential and capability for adaptive management of MPAs to evaluate the accomplishment
of the objectives in complement to a better understanding of how successful MPAs are now
being used around the world. It is important to prepare a management plan, adopt a
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procedure that is understandable and possible to defend as well as a method to help track
the decisions and the value judgments inherent to planning in the protected area. It is
essential that all stakeholders be properly involved in the process to create awareness and
active participation from the different areas such as tourism, fisheries, and community,
among others (Mangi and Austen 2008).
As a result of constraints defined in the management objectives, according to Day
(2002), from the Great Barrier Reef Marine Park Authority, the decision-makers use zoning as
a spatial management tool, which acts similarly as a plan of urban planning. Delimited
zones will have specific goals and purposes of use and management of extractive and nonextractive resource (Villa et al. 2002). In each zone will be allowed certain activities to
occur, but also recognise that other incompatible activities appear in certain areas. Zoning is
considered one of the main pillars of management of protected areas, and has been more
effective when applied with other tools such as regulations, permits, site planning,
monitoring and compliance (Day 2002; Fernandez et al. 2005). It should take into account
the need for biodiversity conservation and sustainable use of environmental resources.
In addition, for proper application of these guidelines there is a need to maintain
effective communication and education to users of the various protected areas for a better
understanding of zoning plans, making them easy to apply these delineations. Another
important objective is to maintain transition or buffer areas for a more efficient protection of
the more strictly protected areas (Kenchington 1991). Under those circumstances, a zoning
area is arbitrary and often reflects the interests of the parties involved in the management
plans, so it must be presented clearly in order to optimise the management and conservation
of resources, and also satisfy the interest groups. These zoning plans will evolve and change
with time according to how they are working for the purpose of the MPA. A multiple-use
zoning approach that manages the entire area as an integrated whole provides a high level of
protection for specific areas, and at the same time, admits a sustainable use of the resources,
including extractive activities, to continue in other zones (Pressey and McNeill 1996).
Boats and threatened marine life
All around the word, boats present a significant hazard for the environment, causing
habitat degradation, pollution and affecting numerous populations of marine and freshwater
animals that are highly endangered in some cases (Wells and Scott 1997; Davenport and
Davenport 2006). An increase in vessels worldwide has been reported due to a combination
of increased population, leisure and the possibility of synthetic, low maintenance materials
usage. This has led to a wider range of boats, from sailboats, speedboats, dinghies, outboardpowered ships, yachts and cruise vessels, among others (Kenchtington 1993; Limpus and
Fien 2009). In addition, boats use more infrastructures, mooring and launching contributing
to pollution and environmental degradation and increase adverse interactions between boats
and wildlife (Wiley et al. 2011, Casale et al. 2010).
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In some parts of the world this has become so critical that the issue has been added
into the Agenda of the International Maritime Organization (IMO, 2007; 2009). Australia,
Spain, USA, and New Zealand, among other countries have well documented studies from
the impacts of vessels to marine mammal, including cetaceans (Van Waerebeek et al. 2007;
Panigada et al. 2006), dugongs (Preen 1992; Preen 2001), manatees (Nowacek et al. 2004)
and less commonly, seals and sea lions. However, rays, birds and turtles are strongly
impacted as well (Burger 1998; Oros et al. 2005).
Motorboats have been implicated in acoustic disturbance, displacement from habitats,
and have created visual disturbances, particularly during breeding, feeding and resting
periods (Preen 1992; Davenport and Davenport 2006, Hodgson y Marsh 2007). Boat strikes
and collisions with ships are a key mortality factor for turtles, large cetaceans, dugongs and
manatees (Preen 2001; Wiley et al. 2011). Some lethal cases, from collisions with boats,
could be sufficient to reduce the viability of the species (Wiley et al. 2011). Powerboats
present the greatest risks, but speed sailing crafts such as catamarans or other types of vessels
can also affect these animals (Lester et al. 2013). According to Heinrich et al. (2012),
mortality of animals occurs as a result from the propeller injuries or the blunt-force trauma
whereas survivors may suffer scars, limb loss, compromised fitness, and decreased
survivorship.
In the regions with heavy boat traffic, these encounters should be expected, and
attempts should be made to minimise their impacts. In the majority of cases, speed
restrictions have been considered the most effective and immediate way to reduce the
interactions among ships and individuals (Calleson and Frohlich 2007; Hazel et al. 2007;
Work et al. 2010). Management plans also have been applied, with closure or limiting
access to areas, diverting commercial marine traffic or propelling guards installed on the
conventional outboard motor (Work et al. 2010).
Marine turtles and boat strikes
Turtles, like dugongs and manatees belong to a group of marine air breathers that are
particularly vulnerable to injuries or death due to ship strikes. Typically found in shallow
waters near the coast combined with the fact that they are slow swimmers, it is difficult to
detect and avoid powerboats and propellers and impact damage is common (Preen 2001).
Several studies conclude that boat strikes are one of the important mortality factors in
numerous near shore turtle habitats worldwide especially in areas of high boat traffic
(Carrillo and Ritter 2010; Denkinger et al. 2013, Hazel et al. 2007; Oros et al. 2005).
In Hawaii, scientist reported that 2.5% of green turtles found dead on the beaches
between 1982 and 2003 had been killed by boat strike (Chaloupka et al. 2010). The case is
worst in Florida were the 13.7% of stranding animals registered were affected by boatrelated injuries (Heinrich 2012), with similar conditions in the Canary Islands, 23% of sea
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turtles found stranded showed lesions from boat strikes or fishing gear (Oros et al. 2005).
Moreover, this could be also associated with different seasons. Casale et al. (2010) described
boat strikes as an important reason of mortality during the warm season in Italian waters.
Boat strikes were also reported off the coast of Gabon attributing to mortality of
Leatherback turtles (Deem et al. 2006). Indeed, boat strikes are registered as a critical threat
even in protected areas that are supposed to be a sanctuary for the species. Dobbs (2001)
recorded a notable vessel-related mortality in the east coast of Queensland including the
World Heritage Area of the Great Barrier Reef. Hazel and Gyuris (2006) found that the
number of dead turtles affected by boat collision reported in the Queensland east coast
appears broadly comparable to that recorded in the Queensland East Coast Trawl Fishery
before the introduction of mandatory turtle-exclusion devices in that fishery.
In the Galapagos Islands, the mortality of sea turtles caused by boat strikes has been
registered during nesting seasons as the second most common cause of mortality after
fisheries by catch (Parra et al. 2011; Zarate et al. 2009). In addition, Denkinger et al. 2013
indicates that the data collected on live observations from foraging grounds in the bays close
to a town located inside of the marine reserve is alarming with 20% of all turtles showing
trauma related with boat strikes.
On the other hand, it seems very likely that in most places, especially in remote areas,
dead turtles are never recorded because stranding reports depend first on the chance of
spotting of a carcass and second on the motivation of individual members of the public to
report a discovery (Hazel and Gyuris 2006). Moreover, it has been described that stranding
probability can be as low as 5% to 20% in some areas, which means that all estimates on
sea turtle mortality should be treated as minimum rates (Denkinger et al. 2013; Hart et al.
2006; Mancini et al. 2011a).
Subsequently, the responses of turtles to boat traffic are not well understood; studies on
shallow bays in Australia conclude that the sea turtles cannot avoid boat collisions unless
boats reduce their speed to 4 km/h (Hazel et al. 2007). Also, tests conducted with a jet
outboard motor resulted in less damage for the animal at either idle or planning speed (Work
et al. 2010). Consequently, Hazel et al. (2007) concludes that the mitigation of risk for turtles
must depend on management intervention. Compulsory speed limits, underpinned by
effective enforcement measures, appear essential if turtles are to be protected in key habitats
subject to vessel traffic.
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The Galápagos Islands
Consists of thirteen larger islands and approximately 115 smaller islets, located in the
eastern Pacific Ocean, 1,000 km off the coast of mainland Ecuador, South America,
straddling the equator at a longitude of 89° - 92° west. Geologically, the Galápagos are
volcanic in origin, and are the result of tectonic movement of the Nazca Plate over a hot
spot in the floor of the Pacific Ocean (Edmond et al. 1979; Wilen et al. 2000). The islands
were discovered first by pirates and buccaneers, then whalers that left their marks in the
archipelago. There are registers that document that until late in the 19th century, sea turtles,
land tortoises and fur seals were killed in tens of thousands. On the other hand, visitors
introduced foreign species like rats, goats and dogs on several of the islands (De Groot
1983).
Colonisation of the islands happened recently compared to other islands in the Pacific
where native people were established many years before. It was not until approximately
1900 that four of the 15 major islands became permanently inhabited (Bensted-Smith et al.
2002; Trueman et al. 2010). Due to the unique and fragile conditions that exist in the
Galapagos, the islands possess extraordinary biodiversity, endemism of species and rich
ecosystems. The colonisation started with the introduction of more species to the islands.
With the increasing population, a regulation was needed to maintain the integrity of the
ecosystems. In 1959, 90% of the land in the islands was declared National Park and the
remaining was declared as urban areas for the people living in Galapagos at that time.
Through management from the National Park, most of the islands were successfully
conserved and for this reason in 1979, UNESCO declared the islands as one of the first
World Heritage Site, acquiring the status of a Biosphere Reserve in 1985 (Quiroga 2009).
In more recent years, the population has increased from a few hundred to more than
25,100 according to the last census in 2010 (INEC 2010). Also, the tourism industry has had
a huge increase of 14% each year from 40,000 tourists in the 1990s to 185,000 in 2011
(GNP Database 2010; Quiroga et al. 2011). Augmenting the pressure on the ecosystems and
human demand are additional issues to be addressed in the archipelago. The most important
economic activity of the island is related to tourism and transport, followed by artisanal
fishing and then small-scale agriculture (Quiroga 2009). In theory, according to De Root
1983, the Galapagos was recognised as one of the most strictly controlled National Parks in
the world. The archipelago has defined regulations and promotes the ecotourism, but in
recent years this boom of tourist and touristic activities represents an increasing problem for
the islands. Therefore, it is necessary to understand how stakeholders perceive current
management regimes so that a truly effective conservation management can emerge
(Hernández Ramírez et al. 2008).
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Oceanographic conditions around Galápagos
The high biodiversity of species of temperate and tropical climate in the Galápagos
exist due to the oceanographic conditions occurring in the area. Houvrnagel (1984)
described the area as one of the most productive areas in the tropical Pacific. This high
productive-waters are fuelled by the confluence of warm currents from the North (North
Equatorial Current-Panama Current), and cold, nutrient rich currents from the South and west
(South Equatorial-Humboldt Current and the Equatorial Undercurrent or Cromwell Current).
The encounter of these currents mixed with a complex topography on the archipelago
creates biogeographic marine areas with a warm mixing zone in the centre, a cool western
area and a warm northern area. This provides an abundant source of food for numerous
species including sea turtles (Denkinger et al. 2013; Edgar et al. 2004; Palacios 2004).
Seminoff et al. (2008), explains the mesoscale features from oceanic waters in this region
like the nutrient-enriched Galápagos plume (Palacios 2002), as important aggregation areas
for a variety of marine organisms. However, the Galapagos is situated in the centre of the
“ENSO Region 3,4” (Sweet et al. 2007), El Niño Southern Oscillation (ENSO) a 3 to 6 years
cycle coupled ocean- atmosphere system of the tropical Pacific. This could affect rich waters
causing drastic declines in productivity and increased water temperatures, having intense
biological consequences. On the other hand, La Niña events respond with negative
anomalies in Sea Surface Temperature and high productivity (Chavez et al. 2002; Denkinger
et al. 2013).
The Galapagos National Park and Marine Reserve
The Galapagos has always been of interest to the scientific community, and many
efforts have been taken towards the protection of such a unique place. Through the
conservation of the islands, Ecuador was a pioneer in conservation efforts in South America
when it declared a number of islands as a protected area in the 1930s and, subsequently,
with the declaration of the National Park in 1959. Since the creation of the National Park,
conservation has focused on: (1) the protection and restoration of native endangered species
and habitats; (2) the control and eradication of exotic species, focusing particularly on the
most invasive flora and fauna; and (3) the environmental education of a rapidly growing
resident population (Edgar et al. 2004).
In addition, in 1998 a Special Law was created for the residents of the islands, in order
to stop the migration from the mainland to the islands. With that law came the creation of
the Galápagos Marine Reserve (GMR), empowered by an Inter-Institutional Authority to
establish a Management Plan by which the GMR was to be managed. The administration and
management of the GMR is in charge of the Directorate of the Galapagos National Park
Service, but with a high degree of participatory management in decision-making. This is
achieved through the forums of participation established by law as the Participatory
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15
Management Board (PMB), built by local users; and the Inter-Authority Management (AIM),
composed of authorities and users, supervises and develops management policies of the
GMR (Altamirano and Aguinaga 2002; Ruttenberg 2001).
Actual Zoning Plan
For the GMR, the regulations and zoning are two of the elements that enable the
management and control of anthropogenic activities in order to minimise potential impacts
to marine ecosystems and to reduce the conflict between uses (Bustamante et al. 2002;
Edgar et al. 2004). The GMR has agreed on a Management Plan, approved in 1999, which
identifies the principles for management of the reserve and permits artisanal fishing, marine
tourism, science and education, navigation and military manoeuvres. The zoning plan of the
Marine Reserve was approved in 2000 as an interim document, which was the product of a
process of dialogue and consensus. It was prepared regarding the information of priority
areas for conservation due to the distribution of biodiversity and the quality of habitat or
species.
This also considered areas of economic value for users and ensured sustainability in
the use of the marine reserve (Piu 2000; Torral-Granda 2005). This zoning is not presented as
rigid, rather a document that is subject to change depending on the circumstances that
emerge and scientific information generated and can be reformulated as necessary to best
fulfil the goals and objectives of the Galapagos Marine Reserve (Piu 2000).
The actual zoning plan is composed of three types of zones, differentiated by the
primary activities permitted and prohibited in each zone. The first zoning area is the deep
water inside and outside the baseline until 40 nautical miles, and it is denominated as a
“Multiple-use zone," where most of the activities are allowed. The second type of zone is
called the “Limited-Use Zone.” It is composed of coastal areas of varying width, which fall
under this limited access designation due to the need to protect vulnerable species and
fragile habitats. This zone is divided into four sub-zones: “protection and comparison,”
“extractive and non-extractive use,” “non-extractive use,” and “temporary special
management” sub-zones. The latter are areas of recuperation or regions of experimentation
also known as “Port Zones,” the regions surrounding the ports where maritime traffic is the
heaviest and there are the fewest use regulations (Davos et al. 2007).
According to Bustamante et al. (2002), the zoning plan and the vision for biodiversity
in Galapagos alleges that it is possible to return and maintain the ecosystems in a natural
state if human activities are controlled. The conservation objectives and policies already
adopted by Ecuador for the GMR and Galapagos as a whole includes no-take areas, with no
extraction of resources, protecting all biogeographic regions, maintaining the function and
structure of biological communities and conserving a sustainable population of all species.
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16
In addition, it emphasises the protection of endangered or migratory species such as
turtles, albatross, whales and sharks, and international treaties and agreements (BenstedSmith et al. 2002). However, scientists agree that the zoning of the GMR needs to implement
a better management approach with a more holistic methodology (Castrejon and Charles
2013; Vinueza et al. 2014). In addition, it is necessary to implement measures to emerging
threats already affecting Galapagos such as tourism, pollution, overexploitation of resources
and climate change, and encourage proper handling to thereby support the conservation and
social-ecological approach of the marine reserve.
Boats and tourism in Galápagos
The majority of the activities related to tourism or fishing in the islands involve boat
transport, including all the ships from ports in mainland Ecuador that supply the
archipelago’s ever-growing population and tourists every week. Marine transportation in the
Galapagos Islands is one of the main drivers of the local economy. However, their use has
consequences on the environment, including, the emission of greenhouse gases, noise
pollution, spill of fuel and lubricants, and animal mortality among others (Jara-Alvear et al.
2013). According to studies in 2008, it was estimated that 93 vessels with a capacity to
accommodate 1,876 tourists operated inside of the GMR. Additionally, a constant flow of
smaller speedboats runs between ports from island to island.
These lines of marine transport have evolved very quickly. Zapata (2005) noted that
until 2004, just two boats from public transportation worked weekly between the islands.
Today, mobility has increased both in number and quality, Denkinger et al. (2013) report at
least 21 speedboats for day tourism and transport in addition to the 71 cruise boats operating
in the marine reserve. Not only have the number of boats increased, but also the power of
their engines; today each vessel has an engine averaging a total of 450-750 horsepower
(Ouvrard and Grenier 2010). The ambition of the local boat owners is to increase the power
of the engines to reduce the travel time between islands and tourist places. Activities such as
island hopping, daily diving and snorkelling tours have grown exponentially over the past
few years. Increasing the boat traffic poses a risk to species that are commonly found near
the surface, including endangered sea turtles (Denkinger et al. 2013; Ouvrard and Grenier
2010).
Marine Turtles in the Galápagos
The Galapagos Marine Reserve hosts four species of the seven species of sea turtles
described worldwide. The Green turtle (Chelonia mydas) is the most abundant specie by far
found in the archipelago, followed by the Hawksbill turtle (Eretmochelys imbricata). The
other two species, the leatherback turtle (Dermochelys coriacea) and Olive Ridley
(Lepidochelys olivacea), are rarely sighted and very scarce in the Galapagos (Green 1994;
Zarate 2002). The majority of the studies conducted in the islands have taken place on
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nesting beaches for green turtles (Green 1994; Green and Ortiz-Crespo 1982; Zarate 2002).
The most important zones are registered in Quinta Playa and Bahia Barahona on Isabela, Las
Bachas on Santa Cruz, Las Salinas on Baltra and Espumilla on Santiago; however nesting
also occurs on all major islands (Green 1984). So far, no nesting sites have been registered
for the other sea turtles species on Galapagos; nonetheless there are important records of
nesting areas in the mainland Ecuador with the exception of the Leatherback turtle (Alava et
al. 2009, Gaos et al.2010).
Studies on nesting areas show that a high percentage of tagged animals on the
Galapagos move to foraging areas to the continental shelf of Central and South America, and
a small group of nesting individuals stay on the archipelago and move between islands
(Green and Ortiz-Crespo 1982; Green 1984; Seminoff et al. 2008; Zárate 2002). On the
other hand, studies made on foraging areas have been proven that individuals shows a high
fidelity, with animals remaining in the area over long periods of time (Carrion-Cortez et al.
2010; Denkinger et al. 2013; Seminoff et al. 2008). In the Galapagos, green turtles feed
mainly on algae, leaves and bark of red mangrove as well as other species of mangroves,
changing the diet composition as the algal biomass and cover decline from the cool to warm
season (Carrion-Cortez et al.2010 ; Green 1993).
Turtles can be seen feeding along most coasts where algae are available, with some
high aggregation areas. According to Green 1993, growth rates are extremely slow. Juveniles
and sub adults with a straight carapace length (SCL) of 40-50cm grow about one cm a year,
and those with an SCL of 50-60cm, about 0.3 cm a year. In the case of Hawksbill turtles,
there is less information about foraging sites in the archipelago; tagged animals show high
fidelity for the areas. According to occasional sightings they are more common in the North
part of the archipelago but unpublished data has found more aggregation of animals all
around the islands.
The zoning structure of the Galapagos protects the animals from fishing pressure; there
are no cases of by catch reported inside of the marine reserve, but along the coast of South
and Central America there could be a significant problem for migrating individuals (Seminoff
et al. 2008). In the case of foraging grounds, most but not all are protected, representing a
threat to the animals. It has been reported that tourism practices and boat traffic modifies
turtle behaviour while resting and feeding activities and boat strikes represent an important
hazard for animals in shallow bays (Carrion-Cortez et al. 2010). The need for better
management efforts is required in order to protect this endanger species.
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METHODS
Study Area
Figure 1. San Cristóbal Island and the main study sites close to the inhabitant area
The study was conducted on San Cristobal Island 0°54'27, 6" S - 89°33'22, 05" W,
located on the southeast part of the GMR. Geologically it is one of the oldest islands of the
archipelago, with a relatively shallow platform but surrounded by deep waters. Most of the
coastal area of the island is volcanic rock and has small sandy beaches. In the underwater
part, there are reef patches in the north and rocky bottoms covered by algae in the South.
The study area is focused in the bays close to the inhabited areas, and the principal
touristic bays and boat trajectories of the island. The major town on the island it is Puerto
Baquerizo Moreno, the second most important port for cruise ships, inter-island traffic and
day tours and the principal fishing port (Denkinger et al. 2013). The town is located in
Shipwreck Bay, in the Southeast part of the island. We collected data from two areas near
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Puerto Baquerizo Moreno; Carola-Baquerizo area (including Baquerizo Bay), which consists
of bays with few patches of sand that have filamentous, brown, green and red algae, and
Lobería-Canon Area (including the southern part of Shipwreck Bay) which is a strip of
shallow rocky reef with a high incidence of mainly green algae and large patches of sand
with greater wave impact in hours of high tide.
The first area including Punta Carola is the closest and busiest area, opening into
Wreck Bay on the northern end of town and thus lies within the main shipping channel for
traffic in and out of Puerto Baquerizo. On the other hand, the second area including Tongo
Reef is mainly used as a surfing spot. The boat traffic in the area is limited to fishing ships
passing close to the coast and a few taxi-panga that are small boats that take surfers or
visitors to the area.
Data Compilation
In order to assess abundance, presence, site fidelity, and home range of sea turtles in
San Cristobal, I utilised the data from the Sea turtle research project (N- PC-20-14)
developed since 2008 in the selected study area.
Boat Surveys/ Census
Water surveys were performed following the "Shark-fishing" method recommended
from Makowski et al. (2005). Two observers, with snorkels and masks, on the back of the
research boat held a five meter rope and were slowly (1 nautical mile/hour) pulled through
the water while the boat was moving parallel to the coast. Observers analysed turtles from
left to right and when an individual was spotted, the boat was stopped and a GPS point was
collected using a Garmin GPS maps62, in addition, the depth, time and specie was
recorded. Though water clarity is needed for accurate performance, this process is a much
more effective way of detecting individuals that counting the turtle heads have since come to
the surface to breathe (Makowski et al. 2005). The census takes place in the same study
areas, Tongo, Carola and Baquerizo, which are characterised by a rocky bottom, while Isla
Lobos and Playa Ochoa are included in order to compare the relative abundance from
places with a sandy bottom.
To analyse the data, the size of the population was estimated through wildlife transects
based on Seber (1982); adapted by Gerrodette and Taylor (2000) for marine turtles. The
number of turtles is estimated by the following equation: N = n / 2wlgA where n = the
number of turtle sightings, l = transect length, w = width of transect next to the tracking line,
g = the visible portion of turtles, and A = the size of the study area.
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Captured and Tagged Individuals
Animals were captured in the different areas described previously. Subsequently a
conventional metal tag, labelled INCONEL ® type # 681 with a four digits number, was
applied. The tags were applied fast and without negative impact to turtles (Balazs 1992).
Morphometric measurements were taken in centimetres: Curved Carapace Length (CCL),
Curved Carapace Width (CCW) and Tail Length (TTL) as per standard methods. In addition,
each turtle was weighed with a precision of ± 0.5 kg (Balazs and Chaloupka 2004);
afterwards, the animals were released on the intertidal area of the same capturing.
Satellite Tracking
Through collaboration of the Galapagos National Park staff and trained field assistants,
three juvenile Hawksbill turtles were tagged with Mk10-AF: Argos transmitter + GPS FastWildlife Computers satellite transmitters. In May 2011, two Individuals were captured in
Punta Carola and one was captured at Lobería, all were caught while free diving with
snorkel gear and the animals were taken to the shore for the tagging process. Individuals
were tagged using epoxy to glue the tags to the top of the carapace. Data were collected in
the ARGOS server and then sent via email to the project researchers. In January 2012, the
decision was made to re-catch the turtles and remove the satellite tags: Two tags were
removed. It was verifiable that the method used did not have any impact on the animals
being studied. Additionally, the individuals were tagged with conventional metal tags
INCONEL ® type # 681. Morphometric measurements were taken in centimetres: Curved
Carapace Length (CCL), Curved Carapace width (CCW) and Tail Length (TTL) as per standard
methods. In addition, each turtle was weighted with a precision of ± 0.5 kg; finally the
animals were released on the intertidal area of the same capturing place.
Acoustic Tracking
Green and Hawksbill turtles were captured and tagged with a coded acoustic VEMCO
V16p transmitter that emits a signal every second (length = 9.5 cm long x 1 cm diameter)
(VEMCO, Halifax, Nova Scotia, Canada). Six male (green turtles) and two juvenile
(Hawksbill turtles) were captured directly by hand using free diving, and the tagging process
was performed inside of a research boat from the project. Transmitters were attached using
small bolts to the posterior margins of the carapace and two electric tides crossed the holes
to keep the transmitter fixed to the carapace according to Seminoff et al. (2002) (Muñoz et
al. in progress). For every individual, morphometric measurements were taken in
centimetres: Curved Carapace Length (CCL), Curved Carapace Width (CCW) and Tail Length
(TL) as per standard methods. In addition, each turtle was weighted with a precision of ± 0.5
kg; finally the animals were returned to the same capturing place.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
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After an acclimation period, marked individuals were actively followed with the use of
a unidirectional hydrophone (VEMCO-VH110) connected to the receiver VR-100 that was
installed in the research vessel. The signal was detected by the hydrophone immersed in
water. A grid was used with sampling intervals of 300 meters with interludes of 3-5 minutes
of listening for each of the turtles. The signal was maintained with an intensity between
70-100 decibels, approximately less than 30m from the animal, the boat was moving close
enough to the animal in a distance considered prudent in order to do not disturb the
followed turtle (Munoz et al. in progress). The animals were followed by a period of at least
± 48 hours. In the end, seven tags were recovered.
Boat Tracks and Boat Traffic
In order to identify the most frequent routes of ships operating from Wreck bay (where
the principal port of San Cristobal is located), to all the touristic places, inter-island trips and
around the island, and a camera (Olympus Stylus Tough TG-2) with GPS were given to one
of the crew-members of the boat being tracked. The camera was scheduled to take a GPS
point every second regardless of whether the camera was on or off. To prevent the vessels
from changing their route, due to knowledge of being monitored, the crew were not
informed that the camera possessed GPS capabilities. The camera was collected when the
boat returned to the port at the end of the journey.
To measure boat activity during the acoustic tracking, information of how many ships
passed next to the study area was recorded and divided into categories of passing fast or
slow. The following categories were used: Speedboat: typically a single-hulled, outboard
powered boat from approximately 4 to 7 m long, Taxi Panga: small single-hulled ship that
serves to transport people around the bay, Dinghies: normally small boats that serve to
transport passengers from touristic ships to ports, and Tour boats: any big vessel entering into
the bay.
Data Analysis
Data Pre-processing
Following the methodology used by Munoz, (2013), the acoustic track data package
was treated by VEMCO Windows PC interface and adapted to a text format (csv). VEMCO
raw data was filtered with a parameter of 75 decibels in the manner that was mentioned
before. In the case of the satellite data, the information was downloaded to the computer. For
the boat tracks, the information was downloaded and the points were exported as text format
(csv) in order to be mapped.
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Spatial Analysis
For the spatial analysis, the study followed the same methodology used by Munoz,
(2013), that analyses the four-first acoustic tracks. The analyses were presented using the OzTrack project. “Software from the UQ e-Research Lab and the UQ Ecology, Conservation and
Organismal Biology (ECO)-Lab at The University of Queensland, copyrighted to the
University of Queensland.” (Web1). The variable estimated in order to analyse home range
and habitat use was the alpha hull estimation, which was selected as the most accurate with
the lowest standard error, compared to the other four possible estimates given by the
program.
Alpha Hull Estimation (AH)
It is a deterministic method that consists in the generation of area polygons similar to
Minimum Convex Polygon. However, unlike MCP, Alpha Hull Polygons are generated by
systematically removing vertices until only the vertices that are shorter than the value of the
requested parameter are preserved. Connecting geographical points using a Delauney
triangulation generates alpha polygons. Fundamentally, this method cut objectively low use
areas generated on the surface of the polygon. While minor is the alpha value, finest is the
resolution of the polygon. If alpha increases, the surface of the polygon increases until it is
equivalent to a 100% MCP. This calculation was carried out in R using The Alpha hull
package (Pateiro-Lopez and Rodriguez-Casal 2011; Web 1).
GIS Analysis
Maps were processed using the geographical information software ARCGIS 10.0, the
MAP tool free software Quantum GIS (http://www.qgis.org) in addition to Map Tool
(www.seaturtle.org). Geographical positions registered with the VR100 VEMCO GPS device
were decimal latitude and longitude, DATUM WGS84. This obtained high-resolution maps
with the distribution of different sets of animals observed. The accuracy of the GPS points
was ± 5 -7m, bathymetry layers were included.
Determining the Risk of Boat Strike
Using ArcGIS 10.0, with the collected data, it is possible to determine the relative risk
of boat strike to sea turtles in the bays of San Cristobal, identifying spatially the areas where
risk is highest. The main paths traversed by boaters was overlaid with the locations of sea
turtles and the home range obtained from the satellite and acoustic tracks throughout the
study area to determine areas where boat strike was possible. The relative probability of boat
strike in a particular area is greater if the path was more heavily used and/or the density of
sea turtles was higher. Shallower areas increase this probability, as does the speed of the
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
23
boat. Once the risk for the areas in San Cristobal is known, in addition to the above data,
previous studies were used to determine the high-risk areas in the entire archipelago.
RESULTS
Surveys and Census – Population Demographics
In total, 35 boat surveys were conducted parallel to the coast in the main study areas;
normally the visibility was around 8.3 ±3.7 meters, and an average effort of 36 ± 6.5 minutes
per census. Overall we completed 6.23 hours of census for Carola/Baquerizo, 5.03 hours
for Lobería/Canon and 5.4 hours for Isla Lobos/Manglecito. The average depth where most of
the turtles were spotted was 8.5 ±3.7 meters with a variation from 2 to 24 meters and a
mode of 7.9 meters.
In total for the three sites we recorded 623 individuals for C. mydas and four
individuals of E. imbricata. The 68.2% of the spotted individuals were juveniles, followed by
19.7% of females and 14.2% of males.
The local population of sea turtles was predicted in the two main areas. For the first
area, Carola/Baquerizo, 848 animals ± 128 95%CI were identified and 1007 animals ±177
95%Cl for Lobería/Canon. The size of the total population in both areas estimated with this
method was 1748 animals ± 321 95%Cl. The demographic specifics are detailed in the
following graph; the total estimation for E. imbricata was 105 animals ±47 95%CI. There
was no significant difference between the two main areas.
Estimated) average) population) size,)
established) with) the) line) transects)
methodology.) Location:) Baquerizo>
Carola.)Transect)average)length:)2.39Km,)
average) transect) width:) 30m.) Days:) 34.)
Species:)Cm:)C.mydas,)Ei:)E.imbricata....................................))
!
!
Estimated) average) population) size)))
established) with) the) line) transects)
methodology.) Location:) Lobería<) Canon.)
Transect) average) length:) 2.52Km,)
average) transect) width:) 30m.) Days:)
34.Species:)Cm:)C.mydas,)Ei:)E.imbricata..
!
...................................)30m.) Days:) 35.Specie:)
Cm:)
Figure 2: Turtle population demographic
results estimated in the study area.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
24
Figure 3: Census of C. mydas and E.
imbricata, using the Shark fishing method in the three different study sites.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
25
Figure 4. Kernel density indicating where
there is greater density of sightings during censuses in transects parallel to the coast.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
26
Captured and Tagged Individuals
Altogether we captured 175 individuals for the entire area, 156 green turtles (C.
mydas) and 19 hawksbill turtles (E. imbricata), animals were measured and tagged with
external metallic marks type INCONEL ®. 82 male green turtles were captured (First record
in the Eastern Pacific), followed by 73 juveniles and 20 females. Standard measurements are
summarised in table 1. Two individuals were nesting females from Isabela (another island
west of San Cristobal) on the shores of San Cristobal.
Table 1. Mean, standard deviation, and range of morphometric measurements taken at
each study site (cm).*n is the sample size of turtle. The weight is expressed in kg.
Specie
C. mydas
Location
Gender
CCL
CCW
HW
TL
TT
Weight
Carola/Baquerizo
n= 35
Juvenile 62.9 (±5.46) 60.15 (±5.52) 9.39 (±0.93) 8.47 (±2.09) 10.45 (±2.64) 33.25 (±9.56)
Min=48 Max=72.9
C. mydas
n= 9
n= 35
Male
C. mydas
n= 8
n= 47
Male
E. imbrincata
Min=67 Max=89
Min=7.6 Max=12.5
Min=8 Max=16
Min=10 Max=21
Min=43 Max=103
Min=67 Max=85
Min=10 Max=12.5
Min=15 Max=42
Min=15 Max=49
Min=45 Max=85
Min=43.5 Max=72
Min=6.8 Max=10.9
Min=6 Max=21
Min=8 Max=25
Min=13.6 Max=65
Min=72.5 Max=86
Min=10.9 Max=12.6
Min=9 Max=22
Min=13 Max=27
Min=54.1 Max=95
80.62 (±5.30) 75.76 (±4.84) 11.27 (±0.79) 32.21 (±8.07) 39.57 (±8.40) 68.91 (±13.31)
Min=65 Max=91
E. imbrincata
Min=9.7 Max=55
Female 81.44 (±4.88) 76.56 (±4.53) 11.57 (±0.56) 12.37 (±4.66) 17.37 (±4.14) 68.14 (±12.56)
Min=76 Max=91
C. mydas
Min= 4 Max=19
Juvenile 61.75 (±7.12) 59.06 (±6.31) 9.13 (±0.96) 8.45 (±4.04) 11.81 (±4.18) 31.81 (±11.47)
Min=43.5 Max=75
C. mydas
Min=3 Max=15
78.16 (±3.81) 74.84 (±3.89) 11.26 (±0.58) 31.63 (±7.24) 38.97 (±8.22) 63.84 (±8.96)
Min=71 Max=86
Loberia/ Canon
n= 22
Min=7.7 Max=11.8
Female 79.88 (±6.49) 75.94 (±6.18) 10.52 (±1.66) 11.88 (±3.14) 14.88 (±4.32) 63.82 (±18.69)
Min=72 Max=90
C. mydas
Min=48 Max=71
Min=62 Max=86
Min=9.5 Max=12.9
Min=17 Max=57
Min=18 Max=54
Min=40 Max=105
Loberia/ Canon-­‐ Carola/Baquerizo n=16
Juvenile 49.46 (±7.97) 42.68 (±6.88) 6.75 (±1.47) 6.54 (±2.04) 7.81 (±2.72) 14.63 (±6.32)
n=3
Female
Min=35 Max=63
Min=28 Max=53
Min=10 Max=4.4
Min=1.3 Max=9
73 (±7.94)
62 (±7.94)
8.97 (±1.05)
9 (±1.73)
Min=67 Max=82
Min=56 Max=71
Min=7.9 Max=10
Min=8 Max=11
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
Min=2 Max=13
Min=6.4 Max=26
12.33 (±1.53) 45.53 (±13.31)
Min=11 Max=14
Min=37.7 Max=60.9
27
Figure 5. Captures, re-captures and individuals that present any type of boat strike of C.
mydas and E. imbricata in the study area.
Boat Strike Incidence
From the captured animals, 35.8% of subjects showed a type of injury caused by
interaction with ships of which 44% belonged to the area of Carola-Baquerizo and 46.2% to
Lobería-Canyon area. While the rest are recorded from the other sampled areas. Most
affected individuals were males (58.2%) followed by juveniles and females. In addition, the
average depth where these animals were captured was 5.4 ± 3.08 meters.
Site fidelity
From the captured individuals, there has been a high rate of recaptures, 38% for the
entire study area, showing movements from the individuals in the different bays. Apart from
the captures, through photo-identification of individuals, it was possible to verify the
presence of hawksbill turtles in Carola and Lobería for four consecutive years (2011-2014).
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
28
Figure 6. Photo-ID methodology in order to identify site fidelity to certain areas in
identified individuals.
Satellite and acoustic tracking
For the satellite tagging, three turtles were tracked over a period of eight months from
May 2011 to January 2012 (Table 6). The tracking period fluctuated from 14 to 228 days.
Standard measurements are summarised in table 3. A high-resolution map is presented with
the home range (alpha hull 60) of the tracked individuals.
In the case of the acoustic telemetry, a total of five males and one female green turtle
(C.mydas) and two juvenile of E. imbricata were tracked in this study. Standard
measurements are summarised in table 3. Active tracking time period varied from 3 to 46
days. Maps detailing the trajectory and depth profiles are detailed. In addition, a map with
home ranges (alpha hull 60) is presented in figure number two in order to analyse the core
areas.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
29
Table 2. Summary of satellite and acoustic tracked individuals
Location
ID
Sp
Gender
Tag
Loberia
108307 E. i mbricata Juvenile MK10
Carola
108308 E. i mbricata Female
Carola
108309 E. i mbricata Juvenile MK10
MK10
Tongo Reef
Destino C. mydas
Male
V16p
Carola
Facilito C. mydas
Male
V16p
Carola
Naufrago C. mydas
Male
V16p
Tongo Reef
Piru
C. mydas
Male
V16p
Tongo Reef
Baquerizo beach
Pluto
C. mydas
Male
V16p
Ryley
C. mydas
Carola
Max
E. i mbricata Juvenile V16p
Carola
Female
V16p
Grifito E. i mbricata Juvenile V16p
Following period (dd/mm/yy)
Ma y 2011/ Ja n 2012
Ma y 2011/ Jun 2011
Ma y 2011/ Sept 2011
11 Ja n/ 13 Ja n 2013
18 Ja n/ 26 Ja n 2013
27 Ja n/ 29 Ja n 2013
15 F eb/ 20 Apr 2014
17 Apr/ 13 Ma y 2014
27 Ma y/ 5 Jun 2014
9 Jun/ 14 Jun 2014
23 Jun/ 29 Jun 2014
Total Mean for Mean Core area length each point speed (Km²)
Total days
(Km)
(Km)
(Km/H)
248
554.61
1.75
0.9
8.68
14
45.87
0.97
0.11
2.82
107
61.92
1.37
0.13
4.92
3
78.15
0.04
1.62
0.48
9
120.29
0.02
0.62
0.57
3
69.26
0.04
1.58
0.68
46
114.38
0.03
0.07
1.05
27
53.99
0.02
0.08
0.41
9
49.99
0.02
0.22
0.09
7
19.93
0.01
0.13
0.03
7
26.56
0.01
0.21
0.07
Figure 7. Habitat preference of the three E. imbricata satellite tagged individuals Zones
with intense colours represent areas of greatest use.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
30
Figure 8. Habitat preference of the four male C mydas followed by acoustic telemetry.
Zones with intense colours represent areas of greatest use.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
31
Figure 9. Habitat preference of a female C. mydas and a male of C. mydas followed by
acoustic telemetry. Zones with intense colours represent areas of greatest use.
Figure 10. Habitat preference of two E. imbricata followed by acoustic telemetry. Zones
with intense colours represent areas of greatest use.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
32
Core Areas
The core areas calculated from acoustic tagged individuals are presented as an
illustration in figure 10 and 11. 50AH core area ranged from 0.03 to 8.68 Km2 (mean= 1.8
± 2.72). Core areas proximity to shore ranged from 0.33 to 0.91 Km (mean=0.5 ± 0.13).
Core area bathymetry ranged from 2 to 60 meters (mean=32.25 +-12.18).
Figure 11. Home range (Alpha hull 60) for E. imbricata. Figure 12. Home range (Alpha hull 60) for C. mydas MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
33
Boat Tracks and Boat Traffic
In total it was possible to obtain 36 tracks from tourism vessels and inter island boats
departing from Puerto Baquerizo Moreno. All the tracked ships were speedboats with a
usual capacity for 25 passengers; each boat had two to three outboards, which amounted to
an average of 520 horsepower. The measured speed from the tracked boats averaged 17±
5.6 knots. Additionally the routes from cargo ships and the most common tourism routes for
bigger vessels were obtained from the DIRNEA in order to create a map with the most
marine transited areas. The map was presented with the home range from the followed
turtles and shows a clear overlapping of the same used areas.
On the other hand, the data from the boat activity shows that the most common vessel
transiting the study area is the speedboats followed by the taxi-panga boats and fishing boats.
The average speed registered was 13.1± 6.73 knots with a mode speed of 10 knots.
400
# o f s ig h tin g s
300
200
100
C a r g o s h i p s
PNG
F i s h i n g b o a t s
T a x i p a n g a
S p e e d b o a t s
0
T y p e o f v e s s e l
Figure 13. Number of vessels registered during the dates of continuous monitoring
25
S p e e d (K n t)
20
15
10
5
C a r g o s h i p s
PNG
F i s h i n g b o a t s
T a x i p a n g a
S p e e d b o a t s
0
T y p e o f v e s s e l
Figure 14. Average speed registered according to each vessel sighted.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
34
Figure 15.Map showing the trajectories of tourism, fisheries and transport vessels in San
Cristobal Island recorded in this study. Each yellow line is a different boat.
Figure 16. Map showing the trajectories of tourism, fisheries and transport vessels in
Galápagos Island recorded in this study. Each yellow line is a different boat.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
35
Figure 17.Habitat use of C.mydas and E. imbricata overlapped with the main vessels routes
(tourism, fishing and transport) operating from San Cristobal Island.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
36
Determining the Risk of Boat Strike
Using a risk assessment approach, a map with the relative impact from transiting boats
to sea turtles was created, evaluating the most probable areas for an impact of sea turtles and
vessels. Recompilation of information of past studies gives the opportunity to expand the risk
assessment to the entire archipelago in order to create recommendations for a boat traffic
management plan.
Figure 18. Probability of vessel strikes (tourism, fishing and transport) with sea turtles in
San Cristobal Island. Areas with the highest colour are the most prone to this type of
anthropogenic impact areas.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
37
Figure 19. Probability of vessel strikes (tourism, fishing and transport) with sea turtles in
the Galapagos Islands. Areas with the highest colour are the most prone to this type of
anthropogenic impact areas.
DISCUSSION
Census and direct observations of sea turtles in aquatic habitats (Demography and
population status)
While some degree of water clarity for the operation of this method is needed, it is a
much more efficient way of detecting turtles than the counting of heads. This method of data
collection was very beneficial as working time was efficient and had a minimal impact or
disturbance to the turtles. The data obtained will be used for management and conservation
because it provides information on demographic and spatial relation between study sites.
Also, by analysing this data, it is possible to estimate habitat preferences.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
38
In this case, the preference for rocky and shallow (8.5 ± 3.7 meters, mode of 7.9
meters.) bottom types appears to be the most common habitat were turtles are spotted (93%
n=583) in comparison with the sandy bottoms (7% n= 43), which have a minimum number
of observations. Similar relationships are possible to observe in Makowski et al. 2005, where
a similar census was conducted and observations of turtles in sandy bottoms were inexistent
(100% n=62, n=79 observations over the reef). Studies made in Galapagos found the same
pattern of a preference in the habitat for individuals in shallow- rocky areas (Seminoff et al.
2002). The habitat preference is used as a parameter in order to determine the possible risk
of a boat strike interaction in the Galapagos archipelago.
In addition, this method could be a base for future comparison; it is basically an
approach in order to assess residence patterns and demographic parameters. This method
has been tested and widely used in places like Hawaii and Florida (Makowski et al. 2005).
Long-term monitoring is needed In order to estimate population abundance and
demographic trends, (Eguchi et al. 2010), so it is not possible at the moment to discuss the
population size in the study area because this is the first survey season. However, from the
first demographic analysis, it is possible to observe that a dominant portion of individuals are
juveniles, this influence may be related to a foraging and growth zone. It is important to
emphasize that, as far of our knowledge there is not a population study effort focus on the
marine and coastal areas on sea turtles at the Galapagos, Ecuador or the Eastern Pacific. In
other words we don’t have a reliable number in order to assess population trends.
Finally, referring to the eastern Pacific population of E. imbricata, experts propose 400
females for the entire area (Gaos et al. 2002). Considering the effort of the 2013-2014
season, which manages the registration of 19 individuals of E. imbricata, and a rough
estimation of 105 individuals by the aquatic census method, places as Galapagos and San
Cristobal Island are now in the map as an important place that need further studies in order
to have conservation.
Captured and tagged individuals. External markings INCONEL ® type # 681 and photo
identification.
Globally most efforts in measuring the population trend of sea turtles have been found
in nesting beaches, mainly due to the accessibility to these sites. However, in recent years
techniques have been developed to monitor these species in other aggregation sites, such as
foraging and breeding sites. The 2013-2014 season provided a systematic effort to
standardise the monitoring in such sites in the Galapagos.
For the first time, a baseline in feeding and breeding areas at San Cristobal-Galapagos
was achieved. The capture and standardised tagging of 159 C.mydas individuals and 19 E.
imbricata individuals was accomplished. Where analysis of relative abundance, standardised
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
39
surveys, biochemical parameters and health status are included. Besides the analysis of
habitat use that will be used as indicators for an efficient zoning for protection.
Also, thanks to the efforts of this season, we have registered for the first time at San
Cristobal, two nesting females tagged on Isabela (an island west of the Galapagos
archipelago) by the GNP-CDF nesting campaigns, thus showing the connectivity between
islands. Studies on nesting areas reveal that a high percentage of tagged animals on the
Galapagos move from nesting beaches in Galapagos to foraging areas to the continental
shelf of Central and South America, and another group of nesting individuals stays on the
archipelago and move between islands (Green and Ortiz-Crespo 1982; Green 1984;
Seminoff et al. 2008). On the other hand studies made on foraging areas show a high fidelity
to the place, with animals remaining in the area over long periods of time (Seminoff et al.
2008; Carrion-Cortez et al. 2010; Denkinger et al. 2013).
Conventional tagging with standardised metal tags on foraging areas, collecting genetic
samples, and a health assessment, among others. It is the priority to generate a plan to
provide consistent information for future wildlife tendencies comparisons (Hamann et al .
2006; Hamann et al. 2010). It is crucial to have uniform and well-established management
plans in order to provide reliable information for the decision makers.
The photo-ID identification system is used as a complement in order to identify
individuals. Gives the possibility of analyse residence patters over the time; the images or
pictures could be taken by tourist and-or naturalist guides without disturbing the animals.
Boat Strike Incidence
The percentage of injured individuals found in the study areas was higher than the one
described from Denkinger et al. (2013), where 19% of the individuals presented a type of
injury from boats. This increase (32.8% for the entire area) could be due to a more intensive
monitoring program or an increase of the interactions between boats and sea turtles. Maps
obtained from the boat tracks overlapping with the home range of tagged individuals, show
that the ships routes passed intensively and continuously above the most used areas for
turtles in the bay. A management plan is crucial in order to reduce this type of interactions
that are affecting the turtles.
There was no significant difference between study sites, so it’s important to create
awareness for the entire area and not just for specific small sites. Turtle individual preference
to certain sites in specific bays that are under high human impact has important implications
for management and conservation. However, long-term scientific studies are needed to
measure their significance.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
40
Acoustic Monitoring
Acoustic telemetry is an important tool for studying marine animals, which allows
tracking of underwater creatures, resulting in high-resolution movements. C. mydas adult
males, usually do not return to land since they hatch, making them elusive creatures (Limpus
and Fien 2009). In this sense their movement patterns and habitat use remain unknown. In
this context, this research provides important information for understanding and therefore
protection. Their habitat and range at some marine areas in the Galapagos is defined, and
the records made at sea have been integrated into a geographic information system. Maps of
the identified habitat have been developed.
By this study we are going to contribute to the rezoning of PNG in order to protect
these species efficiently, mainly in feeding and reproduction areas, which are being affected
across the archipelago mainly by the collision with vessels (Denkinger et al. 2013). The
following research was achieved for the first time in Ecuador with 435 hours of acoustic
active continuous monitoring of C. mydas and E. imbricata individuals at feeding and
breeding areas. The data obtained shows a clear agglutination pattern between Carola Bay
(0o52'51, 93 "south; 89o37'18, 66" west); Shipwreck Bay (0o53'36, 46 "south; 89o37'01,
85" west); and Tongo Reef (0o54'20, 19 "south; 89o37'52, 30" west) near to the most
frequent boat traffic routes.
Core Areas
We observed an overlap in the home range of both species (C. mydas and E.
imbricata); there is a clear preference on the areas close to the shore and with food
availability. The core area is bigger in animals with more monitoring time (juveniles= ≈7
days-0.05 km2, females= ≈9 days-0.09 km2, males= ≈ 17.6 days-0.635 km2) however, in
general it is possible to observe that males have bigger core areas than females or juveniles.
Site Fidelity
From the captured individuals, there has been a high rate of recaptures, 33% for the
entire study area, showing movements from the individuals to and from different bays.
Furthermore, through photo-identification, it was possible to verify the presence of hawksbill
turtles in Carola and Lobería for 4 consecutive years (2011-2014). All the individuals marked
with satellite tags show a high fidelity to the area where the animals were captured. In
addition, it is possible to observe that just one individual (Adult C.mydas male) presents low
fidelity to the area in comparison with the other seven individuals monitored by active
acoustic telemetry.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
41
Determining the Risk of Boat Strikes
Using ArcGIS 10.0, it is possible to determine the relative risk of boat strikes to sea
turtles in the bays of San Cristobal and identifying spatial areas where risk is highest. The
main paths traversed by boaters was overlaid with the locations of sea turtles and the home
range obtained from the satellite and acoustic tracks throughout the study area to determine
areas where a boat strike have the highest likelihood.
The relative probability of a boat strike in a particular area is greater if the path is more
heavily used and/or the density of sea turtles is higher. Shallower areas increase this
probability, as does the speed of the boat. Once the risk for the areas in San Cristobal is
known, in addition to the above data, previous studies (Denkinger et al. 2013; Parra et al.
2013) are used to determine the high-risk areas in the entire archipelago.
Using a risk assessment approach, a map with the relative impact from transiting boats
to sea turtles was created. We evaluate the most probable areas for an impact of sea turtles
and vessels. A literature review Information (Parra et al. 2013; Carrion-Cortez et al. 2010;
Zarate 2000) gives the opportunity to expand the risk assessment to the entire archipelago in
order to create recommendations for a boat traffic management plan.
Conclusions and Recommendations
Galapagos is described as the most important nesting site for green turtles in the
eastern Pacific (Green and Ortiz-Crespo 1982; Zarate et al.; Seminoff et al. 2007). This
species likewise is abundant in foraging and resting places of the archipelago. Recently by
our current efforts we just found as well hawksbill turtles (Muñoz et al. in prep). The results
of this study suggest that the rocky coastal areas are significant areas for these species. In this
sense, to improve the protection of this group of animals within the Galapagos Marine
Reserve, scientific information must be reconciled with human activities.
Acoustic telemetry is an important tool for studying marine animals, which allows
tracking marine wildlife resulting in high-resolution appreciation of their movement ecology
(Allen et al.; Gaos et al. 2012). The plot analysis produced in this research, in conjunction
with the maps produced concerning the movements of tourist vessels and fishing vessels,
will allow us to understand and manage the dynamics of use of selected marine areas and
determine human impact to the sea turtle populations.
On the other hand, it could be verified that the method used does not initiate any
impact on the animal studied. Installing VR2W fixed stations is recommended to passively
record tagged animals and thus supplement the information required.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
42
It is the first time that a study in the Galapagos formally investigated and continuously
monitored these species at their marine coastal habitats. Having completed 111 days of
continuous acoustic monitoring to 6 male individuals of C. mydas and 2 individuals of
E.imbricata, which is new to science in this part of the Eastern Pacific. It is recommended to
continue the monitoring and thus further investigate the feasibility of this population. Longterm studies that serve to answer fundamental questions are needed.
The maps results presented, shows that in the Galapagos C. mydas and E. imbricata at
the time of the survey, move proportionally close to the shoreline at depths no more than 50
meters. Turtles were most frequently seen among Carola Bay (0o52'51, 93 "south; 89o37'18,
66" west); Shipwreck Bay (0o53'36, 46 "south; 89o37'01, 85" west); and Tongo Reef area
(0o54'20, 19 "south; 89o37'52, 30" west). The places with higher densities of turtles are also
the ones with more anthropogenic activities. In this sense, exist a significant number of
individuals interacting with human influences (i.e. Boat collisions). Studies in Australia have
verified the significant impact of collisions between boats and sea turtles (Hazel et al.2006;
Hazel et al.2007).
Although, the GMR is a protected area, that provides a relief from overfishing, resource
exploitation, and maintains a healthy ecosystem for marine species. The present study
confirms the suggestion that one of the greatest current threats is collision with boats (one in
three individuals shows a type of boat interaction from the captured animals), whether due
to tourist or artisanal fishing vessels (Zarate and Carrión 2007; Zarate 2009; Denkinger et al.
2013.). Therefore, to improve the protection of this group of animals within the GMR, the
range of life and habitat use must be known as well as foraging sites and the movement of
populations during the year. In addition it is necessary reconcile this information to human
activities mentioned above.
Furthermore, a crucial part of the population of Eastern Pacific C. mydas and E.
imbricata depends on the nesting, feeding and resting areas present in Galapagos.
Accordingly, the Ecuadorian government needs to be continuous, timely and reliable in
order to protect and manage these populations. This project sought to contribute to research
on aggregations of turtles, which will provide the development of appropriate strategies for
long-term preservation, also assisting the government of Ecuador in implementing the
National Plan of Conservation of Sea Turtles.
Despite being protected by Ecuadorian law, marine turtles still face serious threats
throughout the coast. In this context, it is vital to protect them at different stages of their life
cycle. In the Galapagos, particularly in San Cristobal Island, the turtle individual preference
to certain sites in specific bays, that are under high human impact, have important
implications for management and conservation.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
43
Recommendations for a Boat Management Plan
Goal:
Create a management plan that covers all kinds of boats activities around the islands.
Consequently, reduce the impacts caused to the welfare of animals and ecosystems in
Galapagos.
Strategies:
A. To work with the Galapagos National Park in the new zoning for the Marine
Reserve. Including high risky areas and important foraging and breeding areas for sea
turtles on the archipelago.
B. Increase awareness of boat users about the importance of applying speed
restrictions in order to maintaining safety bays close to the inhabited area of San
Cristobal. Additionally create campaigns to reach boat users in other islands, ensuring
turtle protection on a bigger area.
Recommendations:
1. It is necessary to establish areas with restricted speed limits, in order to not exceed
3-4 knots, giving the opportunity to turtles and other iconic fauna to escape.
2. Encourage the use of an observer in the most likely places for possible interactions
with boats. So, when an individual is sighted, the captain of the boat will slow down and
avoid the individual concerned.
3. Promote reduction of speed to 5 knots in voyages within 3 nautical miles near the
coast.
4. Increase education and enforcement of rules in reproductive or greater abundance
of individuals in different areas.
5. Include in the management plan for marine traffic, all types of vessels circulating
within the Marine Reserve, no matter what activity they are engaged.
6. Maintain and expand the standardised monitoring system of marine and coastal
areas, to find several key areas of the archipelago, to have a larger population analysis
that can be used for the proper management and conservation of the species.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
44
7. Create an education and awareness program dedicated to the people operating in
the speedboats in the Galapagos.
8. Construct an appreciation by boaters of the impact that the vessels has on the fauna
and entirely ecosystem on the islands, in specific the areas close to the inhabited areas
that receive a greater anthropogenic pressure.
9. Install markers of speed limits in the principal bays of the archipelago. And basic
information about the management plan.
10. Use turtles as a flagship specie to attract attention from people interested on help in
the project and to protect other species of the ecosystems (Aguirre y Lutz 2004).
11. Speed restrictions must by apply in shallow areas next to the coast of the islands.
ACKNOWLEDGMENTS
Dr. Mark Hamann (JCU), Juan Pablo Muñoz (USFQ-GSC), Dr. Judith Denkinger
(USFQ), Dr. Carlos Valle (USFQ), Ing. .Carlos Ortega (GNP), Ing.Galo Quezada (GNP), Dr.
Diego Quiroga (USFQ), Eduardo Espinoza (GNP), Renato Herrera (GNP), Jorge Torres (GNP),
Mesias Revelo (GNP), Juan Garcia (GNP), Alexander Gaos (ICAPO), Ernesto Briones (EF),
Danilo Silva (EF), all the volunteers that helps with the project in one or another way, special
thanks to Melissa Alarcon and Jason Castañeda.
I also want to recognise the crucial support and collaboration of the following
institutions: Galápagos National Park (GNP), Universidad San Francisco de Quito (USFQ),
Galápagos Science Center (GSC), Ecofondo Foundation (EF), Ministry of environment,
Eastern Pacific Hawksbill initiative (ICAPO), James Cook University-Australia (JCU) and
Ecuador Secretary of higher education science technology and innovation (SENESCYT).
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45
REFERENCES
Agardy, T. (1999). Global trends in marine protected areas. Trends and Future Challenges for US National
Ocean and Coastal Policy, 51.
Agardy, T., Bridgewater, P., Crosby, M. P., Day, J., Dayton, P. K., Kenchington, R., ... & Peau, L. (2003).
Dangerous targets? Unresolved issues and ideological clashes around marine protected areas. Aquatic
Conservation: Marine and Freshwater Ecosystems, 13(4), 353-367.
Alava, J. J., Pritchard, P., Wyneken, J., & Valverde, H. (2009). First documented record of nesting by the olive
ridley turtle (Lepidochelys olivacea) in Ecuador.
Allison, G. W., Lubchenco, J., & Carr, M. H. (1998). Marine reserves are necessary but not sufficient for marine
conservation. Ecological applications,8(sp1), S79-S92.
Balazs, G. H. (1984, November). Impact of ocean debris on marine turtles: entanglement and ingestion.
In Proceedings of the Workshop on the Fate and Impact of Marine Debris (Vol. 2729). R.
Balazs, G.H. (1992). Innovative techniques to facilitate field studies of the green turtle, Chelonia mydas.
Proceedings of the 12th annual workshop on sea turtle biology and conservation; 25-29 February
1992, Jeckyll Island, Georgia.
Bensted-Smith R, Powell G, Dinerstein E (2002) Planning for the ecoregion. In: Bensted-Smith R (ed) A
biodiversity vision for the Galapagos islands. Charles Darwin Foun- dation and World Wildlife Fund,
Puerto Ayora.
Bjorndal, K. A., Meylan, A. B., & Turner, B. J. (1983). Sea turtles nesting at Melbourne Beach, Florida, I. Size,
growth and reproductive biology. Biological Conservation, 26(1), 65-77.
Bjorndal, K. A., & Bolten, A. B. (1988). Growth rates of immature green turtles, Chelonia mydas, on feeding
grounds in the southern Bahamas. Copeia, 555-564.
Bjorndal, K. A., Bolten, A. B., & Martins, H. R. (2000). Somatic growth model of juvenile loggerhead sea turtles
Caretta caretta: duration of pelagic stage.Marine Ecology Progress Series, 202, 265-272.
Blundell, A. G. (2004). A review of the CITES listing of big-leaf mahogany. Oryx,38(1), 84-90.
Burger, J. (1998). Effects of motorboats and personal watercraft on flight behavior over a colony of Common
Terns. Condor, 528-534.
Bustamante, R. H., Branch, G. M., Bensted-Smith, R., & Edgar, G. J. (2002). The status of and threats to marine
biodiversity. A Biodiversity Vision for the Galápagos Islands: An Exercise for Ecoregional Planning. WWF,
Washington DC, USA.
Calleson, C. S., & Frohlich, R. K. (2007). Slower boat speeds reduce risks to manatees. Endangered Species
Research, 3(3), 295-304.
Carr, A. (1987). New perspectives on the pelagic stage of sea turtle development. Conservation Biology, 1(2),
103-121.
Carrillo, M. & Ritter, F. (2010). Increasing numbers of ship strikes in the Canary Islands: proposals for
immediate action to reduce risk of vessel-whale collisions. Journal of cetacean research and
management,11(2), 131-138.
Carrión-Cortez, J.A., Zárate, P., Seminoff, J.A., (2010). Feeding ecology of the green sea turtle (Chelonia mydas)
in the Galapagos Islands. Journal of the Marine Biological Association of the United Kingdom 90 (05),
1005e1013.
Carrión, J. F., Zárate, P., & Seligson, M. A. (2007). The Political Culture of Democracy in Perú: 2006.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
46
Casale, P., Affronte, M., Insacco, G., Freggi, D., Vallini, C., Pino d'Astore, P., ... & Argano, R. (2010). Sea turtle
strandings reveal high anthropogenic mortality in Italian waters. Aquatic Conservation: Marine and
Freshwater Ecosystems, 20(6), 611-620.
Castrejón, M., & Charles, A. (2013). Improving fisheries co-management through ecosystem-based spatial
management: the Galapagos Marine Reserve. Marine Policy, 38, 235-245.
Chaloupka, M., Work, T.M., Balazs, G.H., Murakawa, S.K.K., Morris, R., (2010). Cause- specific temporal and
spatial trends in green sea turtle strandings in the Hawaiian Archipelago (1982e2003). Marine Biology
154 (5), 887e898.
Chavez, F. P., Pennington, J. T., Castro, C. G., Ryan, J. P., Michisaki, R. P., Schlining, B., ... & Collins, C. A.
(2002). Biological and chemical consequences of the 1997–1998 El Niño in central California
waters. Progress in Oceanography, 54(1), 205-232.
Claudet, J., Osenberg, C. W., Benedetti‐Cecchi, L., Domenici, P., García‐Charton, J. A., Pérez‐Ruzafa, Á., ... &
Planes, S. (2008). Marine reserves: size and age do matter. Ecology letters, 11(5), 481-489.
Cumming, G. S. (2011). Spatial resilience in social-ecological systems (p. 254). London: springer.
Davis, D., & Tisdell, C. (1995). Recreational scuba-diving and carrying capacity in marine protected
areas. Ocean & Coastal Management, 26(1), 19-40.
Davenport, J., & Davenport, J. L. (2006). The impact of tourism and personal leisure transport on coastal
environments: a review. Estuarine, Coastal and Shelf Science, 67(1), 280-292.
Day, J. C. (2002). Zoning—lessons from the Great Barrier Reef marine park.Ocean & Coastal
Management, 45(2), 139-156.,
Deem, S.L., Dierenfeld, E.S., Sounguet, G.P., et al. (2006). Blood values in free-ranging nesting leatherback sea
turtles (Dermochelys coriacea) on the coast of the Re- public of Gabon. Journal of Zoo and Wildlife
Medicine 37 (4), 464e471.
Davos, C. A., Siakavara, K., Santorineou, A., Side, J., Taylor, M., & Barriga, P. (2007). Zoning of marine
protected areas: Conflicts and cooperation options in the Galapagos and San Andres
archipelagos. Ocean & coastal management,50(3), 223-252.
De Groot, R. S. (1983). Tourism and conservation in the Galapagos Islands.Biological Conservation, 26(4),
291-300.
Denkinger, J., Parra, M., Muñoz, J. P., Carrasco, C., Murillo, J. C., Espinosa, E., ... & Koch, V. (2013). Are boat
strikes a threat to sea turtles in the Galapagos Marine Reserve?. Ocean & Coastal Management, 80,
29-35.
Dobbs, K. (2001). Marine turtles in the Great Barrier Reef World Heritage Area: A compendium of information
and basis for the development of policies and strategies for the conservation of marine turtles. Great
Barrier Reef Marine Park Authority.
Edgar, G. J., Bustamante, R. H., Farina, J. M., Calvopina, M., Martinez, C., & Toral-Granda, M. V. (2004). Bias in
evaluating the effects of marine protected areas: the importance of baseline data for the Galapagos
Marine Reserve.Environmental Conservation, 31(03), 212-218.
Edmond, J. M., Measures, C., McDuff, R. E., Chan, L. H., Collier, R., Grant, B., ... & Corliss, J. B. (1979). Ridge
crest hydrothermal activity and the balances of the major and minor elements in the ocean: The
Galapagos data.Earth and Planetary Science Letters, 46(1), 1-18.
Eguchi, T., Seminoff, J. A., LeRoux, R. A., Dutton, P. H., & Dutton, D. L. (2010). Abundance and survival rates of
green turtles in an urban environment: coexistence of humans and an endangered species. Marine
biology, 157(8), 1869-1877.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
47
Fernandes, L., Day, J. O. N., Lewis, A., Slegers, S., Kerrigan, B., Breen, D. A. N., ... & Stapleton, K. (2005).
Establishing Representative No‐Take Areas in the Great Barrier Reef: Large‐Scale Implementation of
Theory on Marine Protected Areas. Conservation Biology, 19(6), 1733-1744
Fuentes, M. M. P. B., Limpus, C. J., Hamann, M., & Dawson, J. (2010). Potential impacts of projected sea‐level
rise on sea turtle rookeries. Aquatic conservation: marine and freshwater ecosystems, 20(2), 132-139.
Gaos, A. R., Lewison, R. L., Yañez, I. L., & Wallace, B. P. others (2012) Shifting the life-history paradigm:
discovery of novel habitat use by hawksbill turtles. Biol Lett, 8, 54-56.
Gaos, A. R., Abreu-Grobois, F. A., Alfaro-Shigueto, J., Amorocho, D., Arauz, R., Baquero, A., ... & Zárate, P.
(2010). Signs of hope in the eastern Pacific: international collaboration reveals encouraging status for a
severely depleted population of hawksbill turtles Eretmochelys imbricata. Oryx, 44(04), 595-601.
Gerrodette, T., & Taylor, B. L. (1999). Estimating population size. Research and management techniques for the
conservation of sea turtles, (4), 67-71.
Green, D. and M. Hurtado. (1978). Ecología de la población de la tortuga verde (Chelonia mydas agassizi) del
Pacífico Este en las Islas Galápagos. Instituto Nacional de Pesca. Segundas Jornadas Ecuatorianas de
Biología.
Green D (1978). The east Pacific green sea turtle in Galapagos. Noticias de Galápagos, Charles Darwin
Research Station (28): 9–12.
Green D, & F Ortiz-Crespo (1981). Status of sea turtle populations in the Central Eastern Pacific. En: KA
Bjorndal (ed.) 1995, Biology and Conservation of Sea Turtles, pp 221–233. Smithsonian Institution
Press, Washington & London.
Green, D. y F. Ortiz-Crespo. (1982). Status of the Sea Turtle Populations in the Central Eastern Pacific.
Smithsonian Institution Press, EE.UU. p 22.
Green, D. (1984). Long-Distance Movements of Galapagos Green Turtles. Journal of Herpetology 18:121–130.
Green, D. (1993). Growth rates of wild immature green turtles in the Galápagos Islands, Ecuador. Journal of
Herpetology, 338-341.
Green, D. (1994). Galapagos Sea Turtles: An overview. En: BA Schroeder & BS Wilheinghon (compilers),
Proceedings of the Thirteenth Symposium on Sea Turtle Biology and Conservation, pp 65–68. NOAA
Technical Memorandum NMFS-SEFSC-314.
Hamann, Mark, Chloe S Schäuble, Tom Simon, and Sammy Evans. (2006). “Demographic and health
parameters of green sea turtles Chelonia mydas foraging in the Gulf of” 2, no. December (2006):
81-88.
Hamann, M, Mh Godfrey, Ja Seminoff, K Arthur, PcrBarata, Ka Bjorndal, AbBolten, et al. (2010). Global
research priorities for sea turtles: informing management and conservation in the 21st century.
Endangered Species Research 11, no. 3.
Halpern, B. S. (2003). The impact of marine reserves: do reserves work and does reserve size matter?. Ecological
applications, 13(sp1), 117-137.
Hart, K.M., Moorseside, P., Crowder, L.B., (2006). Interpreting the spatio-temporal patterns of sea turtle
strandings: going with the flow. Biological Conservation 129, 283e290.
Houvrnagel, G.T (1984) Oceanographic setting of the Galapagos Islands. In: Perry R (ed) Key environments:
Galapagos. Pergamon Press, Oxford, pp 225–231
Hazel, J., & Gyuris, E. (2006). Vessel-related mortality of sea turtles in Queensland, Australia. Wildlife
Research, 33(2), 149-154.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
48
Hazel, J., Lawler, I., Marsh, H., Robson, S., (2007). Boat speed increases collision risk for the green turtle
Chelonia mydas. Endangered Species Research 3, 105e113.
Heinrich, G. L., Walsh, T. J., Jackson, D. R., & Atkinson, B. K. (2012). BOAT STRIKES: AThreat TO THE
SUWANNEE COOTER. Herpetological Conservation and Biology, 7(3), 349-357.
Hernández Ramírez, H. B., Beltrán Morales, L. F., Villarreal Colmenares, H., & Ortega Rubio, A. (2008)
Perceptions of a fishing community about benefits, environmental impacts and use of resources of isla
cerralvo, a protected island in the Gulf of California, Mexico., 33(9), 604–609.
Hirth, H. F. (1980). Some aspects of the nesting behavior and reproductive biology of sea turtles. American
Zoologist, 20(3), 507-523.
Hodgson, A. J., & Marsh, H. (2007). Response of dugongs to boat traffic: the risk of disturbance and
displacement. Journal of Experimental Marine Biology and Ecology, 340(1), 50-61.
Hough, J. L. (1988). Obstacles to effective management of conflicts between national parks and surrounding
human communities in developing countries. Environ- mental Conservation, 15, 129–136.
INEC. (2010). Results from the al variables of the VII population census INEC 2010 .
IUCN. (2014). The IUCN Red List of Threatened Species. IUCN 2014.
Jara-Alvear, J., Pastor, H., Garcia, J., Casafont, M., Araujo, E., Calderon, E., & fur Entwicklungsforschung, Z.
(2013) Embarcaciones solares, una evolución al transporte marino en las islas Galápagos, Ecuador.
Congreso Internacional y Expocientifica. ISEREE2013
Jiménez-Uzcátegui G, Carrión V, Zabala J, Buitrón P, Milstead B (2008) Status of introduced vertebrates in
Galapagos. Galapagos report 2007–2008. Charles Darwin Foundation, Puerto Ayora, pp 97–102
Kelleher G, Bleakley C, Wells S (1995) A global representative system of marine protected areas. The World
Bank, Washington 4 vols
Kenchington, R. A. (1991). Guidelines for establishing marine protected areas(Vol. 3). Iucn.Chapter 7
Guidelines for Planning Marine Protected Areas. Pp.32-35
Kenchington, R. (1993). Tourism in coastal and marine environments—a recreational perspective. Ocean &
coastal management, 19(1), 1-16.
Lester, L. A., Avery, H. W., Harrison, A. S., & Standora, E. A. (2013). Recreational Boats and Turtles: Behavioral
Mismatches Result in High Rates of Injury. PloS one, 8(12), e82370.
León, Y. M., & Bjorndal, K. A. (2002). Selective feeding in the hawksbill turtle, an important predator in coral
reef ecosystems. Marine Ecology Progress Series, 245, 249-258.
Limpus, C. J., Miller, J. D., Paramenter, C. J., Reimer, D., McLachlan, N., & Webb, R. (1992). Migration of green
(Chelonia mydas) and loggerhead (Caretta caretta) turtles to and from eastern Australian
rookeries. Wildlife Research,19(3), 347-357.
Limpus, C. J., & Fien, L. (2009). A biological review of Australian marine turtles(p. 324). Environmental
Protection Agency.
Maitland, R. N., Lawler, I. R., & Sheppard, J. K. (2006). Assessing the risk of boat strike on Dugongs Dugong
dugon at Burrum Heads, Queensland, Australia. Pacific Conservation Biology, 12(4), 321.
Makowski, C., Slattery, R., & Salmon, M. (2005). " Shark Fishing": A Method for Determining the Abundance
and Distribution of Sea Turtles at Shallow Reef Habitats.Herpetological Review, 36(1), 36-37.
Mancini, A., Koch, V., Seminoff, J.A., Madon, B., 2011a. Small-scale gillnet fisheries provoke massive green
turtle (Chelonia mydas) mortality: a case study from Baja California Sur, Mexico. ORYX 46 (1), 69e77.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
49
Mangi, S. C., & Austen, M. C. (2008). Perceptions of stakeholders towards objectives and zoning of marineprotected areas in southern Europe. Journal for Nature Conservation, 16(4), 271-280.
McClanahan, T. R. (1999). Is there a future for coral reef parks in poor tropical countries?. Coral reefs, 18(4),
321-325.
McClenachan, L., Jackson, J. B., & Newman, M. J. (2006). Conservation implications of historic sea turtle
nesting beach loss. Frontiers in Ecology and the Environment, 4(6), 290-296.
Meylan, A.B., and P.A. Meylan. 1999. Introduction to the Evolution, Life History, and Biology of Sea Turtles.
Páginas 3-8 in Eckert, K. L., K. A. Bjorndal, F. A. Abreu- Grobois y M. Donnelly editor. Técnicas de
Investigación y Manejo para la Conservación de las Tortugas Marinas. Grupo Especialista en Tortugas
Marinas UICN/CSE Publicación No. 4 (Traducción al español).
Meylan, P. A., A. B. Meylan, and J. A. Gray. 2011. The Ecology and Migrations of Sea Turtles 8 . Tests of the
Developmental Habitat Hypothesis. Bulletin of the American Museum of Natural History:1–70.
Mortimer, J. A. (1982). Factors influencing beach selection by nesting sea turtles. In Biolog), and conserlation
~[sea turtles, ed. by K. A. Bjorndal, 45-51. Washington, DC, Smithsonian Institution Press.
Nowacek, S. M., Wells, R. S., Owen, E. C., Speakman, T. R., Flamm, R. O., & Nowacek, D. P. (2004). Florida
manatees,< i> Trichechus manatus latirostris</i>, respond to approaching vessels. Biological
Conservation, 119(4), 517-523.
Oros, J., Torrent, A., Calabuig, P., & Déniz, S. (2005). Diseases and causes of mortality among sea turtles
stranded in the Canary Islands, Spain(1998-2001).Diseases of aquatic organisms, 63(1), 13-24.
Ouvrard, E., & Grenier, C. (2010). El transporte de pasajeros por lanchas en Galapagos, en Informe Galapagos
2009 - 2010 (pp. 40–47)
Panigada, S., Pesante, G., Zanardelli, M., Capoulade, F., Gannier, A., & Weinrich, M. T. (2006). Mediterranean
fin whales at risk from fatal ship strikes. Marine Pollution Bulletin, 52(10), 1287-1298.
Palacios DM (2004) Seasonal patterns of sea-surface temperature and ocean color around the Galapagos:
regional and local influences. Deep-Sea Res II 51(1–3):43–57
Parra, M., Andres, M., Jimenez, J., Banks, S,. Keith I., Suarez, J., Flores, D., Munoz, JP. 2013. Assessing vehicle
strike incidence and its spatial distribution in green turtles (Chelonia mydas) in the Galapagos Islands.
Final technical report from the CDF to the WWF. www.darwinfoundation.org.
Parra, M., Deem, S.L., Espinoza, E., 2011. Green turtle (Chelonia mydas) mortality in the Galápagos Islands,
Ecuador during the 2009e2010 nesting season. Marine Turtle Newsletter 130, 10e15.
Pateiro-López, B., & Rodríguez-Casal, A. (2008). Length and surface area estimation under smoothness
restrictions. Advances in Applied Probability, 348-358.
Piu M. 2000. La Reserva Marina de Galápagos: unresumen de las acciones de vigilancia y control de la pesca
ilegal, 1998 y 1999. In: Informe Galápagos 1999–2000. Fundación Natura and WWF. Editores
Asociados, Quito. 11–14.
Pomeroy, R. S., Watson, L. M., Parks, J. E., & Cid, G. A. (2005). How is your MPA doing? A methodology for
evaluating the management effectiveness of marine protected areas. Ocean & Coastal
Management, 48(7), 485-502.
Preen, A. R. (1992). Interactions between dugongs and seagrasses in a subtropical environment (Doctoral
dissertation, James Cook University).
Preen, A. (2001). Dugongs, boats, dolphins and turtles in the Townsville-Cardwell region and recommendations
for a boat traffic management plan for the Hinchinbrook Dugong Protection Area. Great Barrier Reef
Marine Park Authority.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
50
Pressey, R. L., & McNeill, S. (1996). Some current ideas and applications in the selection of terrestrial protected
areas: are there any lessons for the marine environment. In Developing Australia’s representative system
of marine protected areas. Proceedings of technical meeting, South Australian Aquatic Sciences Center,
West Beach, Adelaide (pp. 22-23).
Quiroga D (2009) Galapagos, laboratorio natural de la evolucion: una aproximacion historica. In: Tapia W,
Ospina P, Quiroga D, Gonzales JA, Montes C (eds) Ciencia para la sostenibilidad en Galapagos. Parque
Nacional Galapagos, Ecuador
Quiroga, D., Mena, C., Karrer, L., Suzuki, H., Guevara, A., & Murillo, J. C. (2011). Dealing with climate change
in the Galapagos: adaptability of the tourism and fishing sectors. Climate Change Vulnerability
Assessment of the Galápagos Islands, 81.
Roberts, C. M., Hawkins, J. P., & Gell, F. R. (2005). The role of marine reserves in achieving sustainable
fisheries. Philosophical Transactions of the Royal Society B: Biological Sciences, 360(1453), 123-132.
Ruttenberg, B. 2001. Effects of Artisanal Fishing on Marine Communities in the Galápagos Islands.
Conservation Biology 15: 1691 - 1699
Sanchirico, J. N., Malvadkar, U., Hastings, A., & Wilen, J. E. (2006). When are no-take zones an economically
optimal fishery management strategy?.Ecological Applications, 16(5), 1643-1659.
Seber, G.A.F., 1982. The Estimation of Animal Abundance and Related Parameters, 2nd Edition. Griffin,
London.
Seminoff, J., a Resendiz, and W. Nichols. 2002. Home range of green turtles Chelonia mydas at a coastal
foraging area in the Gulf of California, Mexico. Marine Ecology Progress Series 242:253–265. doi:
10.3354/meps242253.
Seminoff, J.A., P. Zarate, D.G. Foley, D. Parker, B.N. Lyon. 2007. Post-nesting migrations of Galapagos Green
turtles Chelonia mydas in relation to oceanographic conditions: Integrating satellite telemetry with
remote sensed ocean data. Endangered species Research.Vol. Preprint 2007.
Seminoff, J. A., & Shanker, K. (2008). Marine turtles and IUCN Red Listing: a review of the process, the pitfalls,
and novel assessment approaches. Journal of Experimental Marine Biology and Ecology, 356(1), 52-68.
Seminoff, J. A., Zárate, P., Coyne, M., Foley, D. G., Parker, D., Lyon, B. N., & Dutton, P. H. (2008). Post-nesting
migrations of Galápagos green turtles Chelonia mydas in relation to oceanographic conditions:
integrating satellite telemetry with remotely sensed ocean data. Endangered Species Research,4(1-2),
57-72.
Seminoff J. A. y P. Zarate. 2008. Satellite-tracked migrations by Galápagos green turtles and the need for
multinational conservation efforts. Current Conservation 2.2:11-13.
Sumaila, U. R., Guénette, S., Alder, J., & Chuenpagdee, R. (2000). Addressing ecosystem effects of fishing using
marine protected areas. ICES Journal of Marine Science: Journal du Conseil, 57(3), 752-760.
Swartz, W., Sala, E., Tracey, S., Watson, R., Pauly, D. (2010). The Spatial Expansion and Ecological Footprint of
Fisheries (1950 to Present). PLoS ONE 5(12): e15143. doi:10.1371/journal.pone.0015143
Sweet WV, Morrison JM, Kamykowski D, Schaeffer BM, Banks S, McCulloch A (2007) Water mass seasonal
variability in the Galapagos Archipelago. Deep-Sea Res I 54:2023–203
Tapia W, Patry M, Snell H, Carrión V (2000) Estado actual de los vertebrados introducidos a las islas Galapagos.
Fundación Natura: Informe Galapagos 1999–2000, Quito, Ecuador.
Torral-Granda, M. V. (2005). Requiem for the Galápagos sea cucumber fishery.SPC Bechede-Mer Information
Bulletin, 21, 5-8.
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
51
Trueman, M., Atkinson, R., Guézou, A., & Wurm, P. (2010). Residence time and human-mediated propagule
pressure at work in the alien flora of Galapagos. Biological invasions, 12(12), 3949-3960.
Van Waerebeek, K., Baker, A. N., Félix, F., Gedamke, J., Iñiguez, M., Sanino, G. P., ... & Wang, Y. (2007). Vessel
collisions with small cetaceans worldwide and with large whales in the Southern Hemisphere, an
initial assessment. Latin American Journal of Aquatic Mammals, 6(1), 43-69.
Villa, F., Tunesi, L., & Agardy, T. (2002). Zoning Marine Protected Areas through Spatial Multiple‐Criteria
Analysis: the Case of the Asinara Island National Marine Reserve of Italy. Conservation Biology, 16(2),
515-526.
Vinueza, L., Post, A., Guarderas, P., Smith, F., & Idrovo, F. (2014). Ecosystem-Based Management for Rocky
Shores of the Galapagos Islands. InThe Galapagos Marine Reserve (pp. 81-107). Springer International
Publishing.
Walsh, S. J., & Mena, C. F. (Eds.). (2012). Science and Conservation in the Galapagos Islands: Frameworks &
Perspectives (Vol. 1). Springer.
Wells, R.S., and M.D. Scott. 1997. Seasonal incidence of boat strikes on Bottlenose Dolphins near Sarasota,
Florida. Marine Mammal Science 13:475–480.
Wilen, J. E. (2000). Incorporating space into fisheries models: comment.American journal of agricultural
economics, 1210-1212.
Wiley, D. N., Thompson, M., Pace III, R. M., & Levenson, J. (2011). Modeling speed restrictions to mitigate
lethal collisions between ships and whales in the Stellwagen Bank National Marine Sanctuary,
USA. Biological Conservation,144(9), 2377-2381.
Wilson, C., & Tisdell, C. (2001). Sea turtles as a non-consumptive tourism resource especially in
Australia. Tourism Management, 22(3), 279-288.
Work, P. A., Sapp, A. L., Scott, D. W., & Dodd, M. G. (2010). Influence of small vessel operation and propulsion
system on loggerhead sea turtle injuries.Journal of Experimental Marine Biology and Ecology, 393(1),
168-175.
Zapata, F. A., Gaston, K. J., & Chown, S. L. (2005). The Mid‐Domain Effect Revisited. The American
Naturalist, 166(5), E144-E148.
Zarate, P., Dutton, P., 2002. Tortuga verde. In: Danulat, E., Edgar, G.J. (Eds.), Reserva Marina de Galápagos.
Línea Base de la Biodiversidad. Fundación Charles Darwin/Servicio Parque Nacional Galápagos,
Ecuador, pp. 305e323.
Zarate, P., 2009. Amenazas para las tortugas marinas que habitan el archipiélago de Galápagos. Fundación
Charles Darwin. Presentado al Parque Nacional Galápagos, Ecuador, p. 50.
WEB 1: http://oztrack.org/
MARINE TURTLES AND BOATS IN THE GALÁPAGOS - DANIELA ALARCÓN
52