Hawksbill Sea Turtle Research Papers (original) (raw)

Five species of reptiles present in tropical Australia are considered in this study. These are the hawksbill turtle (Eretmochelys imbricata); the northern long-necked turtle (Chelodina rugosa); the taipan snake (Oxyuranus scutellatus); the freshwater crocodile (Crocodylus johnstoni); and the saltwater crocodile (Crocodylus porosus). Background information is provided on the ecological status of each of these species and after outlining their human use (including commercial use) and management in Australia, an experimental survey method is introduced and results from its application are reported and analysed. The survey method involves two serial surveys of a sample of 204 Brisbane (Australia) residents. The first survey is based on the initial knowledge of the respondents of the reptile species and for the subsequent survey the knowledge available to participants about these species is experimentally increased. These surveys provide information on the amount of knowledge possessed by this sample of the public about the relevant reptile species, the respondents’ attitudes to these species (including their attitudes to commercial use), respondents’ support for the survival of these reptiles and for their conservation. Furthermore, data is gathered from the surveys on the comparative amount respondents’ state they would be prepared to contribute to support the conservation of each of these focal reptile species. Respondents are asked to assume that they are given $1,000 and that this can only be allocated to the conservation of these reptiles. Later, however, they are also given the option to donate this money to any charity concerned with human welfare. The contingent valuation data for each of the reptile species are used to isolate factors that influence the comparative allocation of conservation funds to each of the relevant reptile species. Factors considered include the extent of the respondents’ knowledge of the species, the stated degree to which respondents’ reported that they liked or disliked the species, and ethical views of the respondents. Implications of the findings for the theory of economic valuation of wildlife species and for of the focal reptile species in Australia are discussed in concluding this chapter.

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- Ecological Economics, Tropical Ecology, Australia, Wildlife Conservation

Here we examine the successes, challenges and lessons learned from the Arnavon Islands Community Marine Conservation Area (ACMCA) which was first established in 1995. We review relevant literature and use material from interviews conducted with 28 key informants, all of whom have had a significant involvement in the ACMCA at some stage.
The ACMCA aims to conserve all species inhabiting the Arnavon Islands, but the primary inspiration for funding the work has been the presence of a large hawksbill turtle rookery on the islands. The turtles, were recognised as seriously threatened by hunting by the 1960s, and became the focus of systematic research and protection efforts by the mid-
1970s. After initial conservation failures, the government scientists and conservationists recognised that they needed to involve the adjacent communities of Kia, Wagina and Katupika in the conservation project in order for it to succeed.
A coordinated process of consultation and negotiation therefore commenced in the early 1990s and culminated in the establishment of the ACMCA in 1995. A national ban on the export of hawksbill shells (‘bekko’ or ‘tortoiseshell’) was also enacted into law in 1993.
Recent analysis of long term data on the hawksbill nesting population at Arnavons by Hamilton and collaborators (2015) has demonstrated unequivocally that there has been significant recovery. This review has been commissioned to examine the primary reasons for this, along with remaining challenges and lessons learned thus far from the experience.
Along with most of our interviewees, we are unable to separate the importance of the spatial protection that the ACMCA has afforded nesting female hawksbills, from the broader protective effects of the ban on bekko exports that was implemented two years prior to the commencement of the spatial protection. Both are likely to have been important.
However recent data shows that most of the 20 nesting hawksbill females, fitted with satellite trackers in the last two years at Arnavons swam almost directly to the relative safety of the Great Barrier Reef in Queensland, Australia. This means that, whilst in the Solomon Islands, the protection afforded by the ACMCA may be more significant than the bekko export ban because the turtles do not move around the rest of the Solomon Islands.
The great majority of our interviewees stressed that there has been a steady increase in local acceptance of the desirability of preventing overharvesting of turtles and other marine resources at Arnavons. But poverty, the failure of a seaweed farming project at Wagina, and the existence of a lucrative black market for bekko will continue to drive a small number of people, particularly at Wagina, to continue poaching turtle, which means that the maintenance of the ranger station on Kerehikapa Island in the Arnavons is important for continued conservation.
There has also been a significant increase in appreciation of the intrinsic or existence value of turtles among many members of the ACMCA communities. This appears to have been largely driven by increased knowledge about them, which can be credited to the efforts of a number of conservationists who have shared their scientific knowledge of turtles
and other marine fauna to community stakeholders.
Community members expressed their appreciation of learning about the biology and ecology of the protected fauna, as well as their desire to learn more. They requested that all visiting scientists in future make greater efforts to engage with the communities to share their research findings and explain their interests to the community.

- by Simon Foale and +1
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- Conservation, Marine Protected Areas, Fisheries Management, Sea Turtles

Presentamos esta estrategia didáctica con información básica sobre las distintas especies de Tortugas Marinas, los problemas que enfrentan y algunas sencillas acciones que pueden ayudar a estos bellos reptiles que han surcado el océano... more

- by מישה קאנו
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- Education, Biology, Sea Turtles, Elearning and Distance Learning Eductaion

My report published by the United Nations General Assembly, April 18, 2005.

- by Robert Ovetz, Ph.D.
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- International Relations, International Law, Fisheries, Marine Protected Areas

The hawksbill turtle (Eretmochelys imbricata
(Linnaeus, 1766)) occurs in all of the world’s tropical and
temperate oceans. Hawksbill turtle nesting is widespread
and in some areas abundant within the Indian Ocean and
South-East Asia (IOSEA) region. As is common for widely
distributed and long-lived marine species, determining
the hawksbill’s conservation status at managementrelevant
scales has been challenging (Meylan and
Donnelly 1999; Mortimer and Donnelly 2008; Wallace et
al. 2011; FitzSimmons and Limpus 2014). Similar to other
marine turtle species, the hawksbill turtle is comprised of
numerous individual populations, which nest in separate
locations to one another and often display distinct life
cycle characteristics (FitzSimmons and Limpus 2014).
Yet different nesting populations may also share nursery
and foraging areas (Vargas et al. 2016; Bell and Jensen,
2018). As a result, conducting global status assessments
(e.g. IUCN Red List framework) has proven challenging
and sometimes controversial (Godfrey and Godley 2008).
However, for conservation strategies to be effective,
it is crucial to identify the relationships between the
geographic areas used by each population, thereby
allowing the identification of anthropogenic threats and
impacts at the population level (FitzSimmons and Limpus
2014) and the implementation of effective management.
There have been several attempts to categorise
marine turtles into distinct population units below the
species level, but above the nesting population level. The
development of population genetics was used to determine
genetically distinct populations, and subsequently to
classify these populations as stocks or management
units (as per Moritz 2002). The IOSEA region hosts at
least eight hawksbill management units that nest within
the region; a ninth management unit nests just outside
the IOSEA, although non-reproductive individuals occur
within the region (FitzSimmons and Limpus 2014; Vargas
et al. 2016). Moreover, additional management units
could potentially occur in various locations throughout
the IOSEA region where hawksbills nest but where no
genetic data are available (FitzSimmons and Limpus
2014). Given that knowledge gaps in genetic structure
exist for many regions of the world, Wallace et al. (2010a)
introduced the concept of regional management units
(RMUs) for all seven marine turtle species.

Hybridization between hawksbill (Eretmochelys imbricata) and loggerhead (Caretta caretta) breeding groups is unusually common in Bahia state, Brazil. Such hybridization is possible because hawksbill and loggerhead nesting activities overlap temporally and spatially along the coast of this state. Nevertheless, the destinations of their offspring are not yet known. This study is the first to identify immature hawksbill × loggerhead hybrids (n = 4) from this rookery by analyzing the mitochondrial DNA (mtDNA) of 157 immature turtles morphologically identified as hawksbills. We also compare for the first time modeled dispersal patterns of hawksbill, loggerhead, and hybrid offspring considering hatching season and oceanic phase duration of turtles. Particle movements varied according to season, with a higher proportion of particles dispersing southwards throughout loggerhead and hybrid hatching seasons, and northwards during hawksbill season. Hybrids from Bahia were not present in important hawksbill feeding grounds of Brazil, being detected only at areas more common for loggerheads. The genetic and oceanographic findings of this work indicate that these immature hybrids, which are morphologically similar to hawksbills, could be adopting behavioral traits typical of loggerheads, such as feeding in temperate waters of the western South Atlantic. Understanding the distribution, ecology, and migrations of these hybrids is essential for the development of adequate conservation and management plans.

- by Julia Reisser and +1
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- Hybridization, Brazil, Hawksbill Sea Turtle, Bahia
- by Ian G Baird
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- Vietnam, Endangered Species, Sea Turtles, Viet Nam

Hawksbill shell (tortoiseshell) is still commonly utilized in the Dominican Republic (DR) in the manufacture of hand crafts sold in tourist souvenir shops (locally known as gift shops). Through interviews conducted from January of 2001 to January of 2002, we determined that 29% of gift shops from around the country openly offered this type of merchandise. Necklaces, hand bags, and bracelets were the most popular items. Additionally, we confirmed the existence of at least one gift shop in Santo Domingo in which unworked (raw) shell was stored in sacks of approximately 300 kg each. The owners of this shop indicated that they received this amount of shell every 15-20 days from local vendors. Using allometric growth equations on measures taken of shell scutes from 46 individual hawksbills, we estimated that these ranged in size from 69.9-97.7 cm straight carapace length, indicating that they were either adults or large juveniles. Given the depleted status of adult-sized hawksbills in the country, it is possible that significant amounts of tortoiseshell are being smuggled into the DR from other countries in the area. The importation of tortoiseshell by gift shops, as well as its exportation by customers (usually international tourists) constitute violations of the CITES. Furthermore, this trade, even on a domestic level, constitutes a violation of local legislation as well as a serious threat for the regional recovery of this critically endangered species.

- by Antonia Marte
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- Dominican Republic, Hawksbill Sea Turtle, Tortoises, Tortugas Marinas

Since 2011 FUNZEL has implemented the Sea Turtle Conservation and Improvement of Coastal Communities Livelihoods Program with the objective of strengthening communities through the conservation of the four sea turtle species that nest along the Salvadoran coast. The program is comprised of five components: Management of sea turtle
egg incubation beaches and hatcheries, Financing and sustainability mechanisms, Community development, Public awareness and Research.

Leatherback turtles (Dermochelys coriacea) are the largest species of marine turtle and the fourth most massive extant reptile. In temperate waters they maintain body temperatures higher than surrounding seawater through a combination of insulation, physiological, and behavioural adaptations. Nesting involves physical activity in addition to contact with warm sand and air, potentially presenting thermal challenges in the absence of the cooling effect of water, data are lacking with which to understand their nesting thermal biology. Using non-contact methods (thermal imaging and infrared thermometry) to avoid any stress-related effects, we investigated core and surface temperature during nesting. The mean ± SE core temperature was 31.4 ± 0.05 °C and was not correlated with environmental conditions on the nesting beach. Core temperature of leatherbacks was greater than that of hawksbill turtles (Eretmochelys imbricata) nesting at a nearby colony, 30.0 ± 0.13 oC. Body surface temperature showed regional variation, the lateral and dorsal regions of the head were warmest while the carapace was the coolest surface. Surface temperature increased during the early nesting phases, then levelled off or decreased during later phases with the rates of change varying between body regions. Body region, behavioural phase of nesting and air temperature were found to be the best predictors of surface temperature. Regional variation in surface temperature were likely due to alterations in blood supply, and temporal changes in local muscular activity of flippers during the different phases of nesting. Heat exchange from the upper surface of the turtle was dominated by radiative heat loss from all body regions and small convective heat gains to the carapace and front flippers.

- by Thomas J Burns and +1
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- Thermoregulation, Thermography, Sea Turtles, Hawksbill Sea Turtle

Managing hawksbill turtle populations for use and conservation requires (i) adequate scientific understanding of their population status and dynamics and (ii) consideration of the public’s attitudes to this species. This study employs experimental surveys to assess the Australian public’s attitudes towards the hawksbill turtle, their knowledge of it, their views about its sustainable commercial harvesting, and their support and financial contribution for the species’ conservation. Contingent valuation reveals that the Australian public’s willingness to contribute to the conservation of the hawksbill turtle is high even in comparison to threatened Australian bird and mammal fauna. Most of this stated contribution is based on the intrinsic (non-use) value associated with the hawksbill turtle. It seems that the Australian public will only accept its harvesting if the sustainability of this is assured and its population is more secure. The CITES categorisation of the hawksbill as an Appendix I species hampers the development of techniques for its sustainable use.

- by Clement Tisdell
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- Wildlife Conservation, Sea Turtles, Marine Turtles, Hawksbill Sea Turtle

In this study 14 species of marine leeches (Piscicolidae) are reported. These are divided geographically into northern and southern species, and ecologically into brackish water and high salinity species. Notice is made of Cape Hatteras... more

- by Roy T Sawyer
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- Marine Biology, Parasitology, Marine Ecology, Fish Biology
- by Jack Frazier
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- Marine Mammals, Marine mammals (Marine Conservation), Red Sea, Hawksbill Sea Turtle
- by Juan Jose Alava
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- Ecuador, Sea Turtles, Hawksbill Sea Turtle, Sea Turtle Biology and Conservation

The Hawksbill Turtle Eretmochelys imbricata is classified as Category 1 ‘Critically Endangered’ (Baillie & Groombridge, 1996). It’s nesting on Aride has been monitored since 1976. Although the nesting population on Aride is small in comparison to other sites in Seychelles, the natural beach habitat and protection from poachers makes Aride an important breeding ground and it is vital that monitoring is continued. This paper presents the findings of the 2000-2001 nesting season.
Overall the 2000-01 Hawksbill nesting season was very successful. This is due to the protection afforded by the nature reserve, and the general trend in an increase in emergences and nests is encouraging. Unfortunately there were no Green Turtle Chelonia mydas emergences in the 2000-01 season. This is probably due to the low number of individuals nesting on Aride (Dugdale, 2002) and with turtles nesting every two to three years, there will be years without Green emergences.

- by Hannah Dugdale
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- Hawksbill Sea Turtle, Aride Island, Seychelles

Sea turtles in Ecuador are threatened by diverse anthropogenic stressors. The Guayaquil Gulf is the largest estuary along the Pacific coast of South America and commercial trade route in Ecuador. This bioregion seems to be an important foraging ground for hawksbill sea turtles (Eretmochelys imbricata), as well. Based on field observations and information provided by secondary sources, we report two important sightings of hawksbills, including a juvenile (CCL= 40 cm) and mature female (CCL = 74 cm), observed in the Gulf of Guayaquil in 1999. These findings were the first records of this species in riverine mangroves and estuaries for Ecuador’s mainland coast where the Gulf of Guayaquil constitutes a suitable ecosystem for hawksbills, which have managed to adapt as a response to the reduced availability of healthy habitats in their distribution area. The occurrence of hawksbills in the Guayaquil Gulf demonstrates the importance of estuarine habitats as feeding grounds for this threatened species, highlighting the imperative need of protection measures needed to enhance resilience of hawksbills and conservation actions for this special ecoregion.

- by María José and +1
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- Ecuador, Hawksbill Sea Turtle, Sea Turtle Biology and Conservation, Fisheries Bycatch

In the communities of the West Coasts of Puerto Princesa City, aside from animal predation, poaching of sea turtles for meat and collection of its eggs for human consumption has been a practice of the locals and according to them sea turtles has been part of their traditional diet. Despite of the laws protecting these creatures, these practices still continue and if not arrested, the future generations may not encounter a single sea turtle nesting on their beaches.

- by Corazon Liwanag
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- Hawksbill Sea Turtle, West Philippine Sea, Green Sea Turtles, Olive Ridley Turtle
- by Lucy Hawkes and +3
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- Conservation Biology, Conservation, Caribbean, Sex ratio
- by Júlia Reisser
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- Hybridization, Brazil, Hawksbill Sea Turtle, Bahia

By accident, the world-famous brewery Carlsberg became a central force in global marine science during the first three decades of the 20th century. Within a core group of scientists and managers, Johannes Schmidt (1877-1933) was the key figure combining the efforts of the International Council for the Exploration of the Sea (ICES), the Danish state and several private companies. Launching 26 oceangoing expeditions Schmidt made landmark discoveries such as the breeding ground for the Atlantic eel in the Sargasso Sea. The scientific frontier was pushed literally kilometres into the deep sea and across the World’s oceans. While the formal North Atlantic Empire of the small state of Denmark was in decline, an informal empire of science was erected instead.

- by Bo Poulsen
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- History, European History, History of Science and Technology, Cultural History

The Dumbarton Oaks Maya mosaic mask is shown to have included tortoiseshell on an earlobe—remarkable since this is the only demonstrated use of this material in pre-Hispanic Mesoamerica. The authors present diagnostic evidence for the presence of tortoiseshell, account for its absence in pre-Hispanic artefacts because of decay, and propose its use (in the mask) as being symbolic of the ocean.

- by Reiko Ishihara-Brito
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- Archaeology, Mesoamerican Archaeology, Taphonomy, Maya Archaeology

Five species of marine turtle occur in the Egyptian Red Sea and three are recognised by local fisher men: Eretmochelys imbricata (L.), Chelonia mydas (L.), and Dermochelys coriacea (L.). The last named is rarely sighted, and although the other two nest, only Eretmochelys is common; possibly 500 nest yearly, mainly on offshore islands. Both nesting and feeding habitats appear to be extensive for this species. but clutches have am unusually high percentage of yoIkless eggs. The significance of this is not understood, but it indicates that the animals are under pressures not experienced in other parts of their range. The small population of Chelonia is probably due to the scarcity of feeding habitat; marine pastures are generally small in area and standing crop. Derrnochelys may be rarely sighted because local fishermen infrequently venture into epipelagic waters where this animal is most common, but the available data indicate that the species is a vagrant in Egypt. The enormous swarms (Jellyfish that occur in the Egyptian Red Sea evidently do not attract these turles, although seasonal concentrations of jellyfish are often accompanied by Derrnochclys in other seas. Exploitation of' turtles, mainly for meat and eggs, is slight, but habitat perturbations are intense from oil pollution and marine explosions. There is a great need/or more basic information and rigorous management of the marine environment.

This work provides novel information on the distribution and abundance of sea turtles, as well as identification of sea turtle species in foraging areas around of Serrana and Serranilla islands—the northernmost area of the Colombian... more

- by Robert Ovetz, Ph.D.
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- Fisheries, Marine Protected Areas, United Nations, Marine Conservation

This study represents the first record of the critically endangered hawksbills sea turtle, Eretmochelys imbricata, in Argentina, the most austral report of this species. According to Pritchard and Mortimer (1999) individuals were identified as Eretmochelys imbricata demonstrating the most austral record of this critically endangered sea turtle species, in temperate waters of Argentina. The analysis of 760 bp fragment of mitochondrial DNA control region sequences indicated that the Brazilian nesting colonies might be one of the main contributors to these latitudes and showed the hybrid nature of individuals. Our results constitute the first insight into the occurrence and characterization of this tropical species in temperate latitudes, improving our knowledge about its migratory patterns in the region results suggest that the Brazilian nesting colonies might be one of the main contributors to Argentinean feeding areas.

The Dimaniyat Islands in the Gulf of Oman, an archipelago of nine uninhabited islands, surrounded by coral reefs, provide good feeding and nesting grounds for hawksbill turtles Eretmochelys imbricata. This is probably the densest population of hawksbill on earth for this species, with at least 250 females per year nesting on 1.5 Km of beaches (Salm, 1991; Salm et al., 1993; Mendonça, 1999). Green turtles Chelonia mydas also nest on the islands (Salm, 1991). During the nesting seasons of 1999 and 2000, research was carried out on the Dimaniyat Islands. Predators of turtle eggs and hatchlings on turtle nesting beaches were identified and their abundance estimated. The qualitative impact of predation on the turtle population is also discussed. Crab abundance was based on counts in 10 quadrats of 3m*3m in April and June 1999, at two beaches chosen randomly on D1 island. Impact of crabs on turtle eggs is discussed based on distance between crab hole and tidal mark and turtle nest chamber...

- by Vanda M D Mendonca
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- Conservation Biology, Hawksbill Sea Turtle, Dimaniyat Islands

The complex processes involved with animal migration have long been a subject of biological interest, and broad-scale movement patterns of many marine turtle populations still remain unresolved. While it is widely accepted that once marine turtles reach sexual maturity they home to natal areas for nesting or reproduction, the role of philopatry to natal areas during other life stages has received less scrutiny, despite widespread evidence across the taxa. Here we report on genetic research that indicates that juvenile hawksbill turtles (Eretmochelys imbricata) in the eastern Paciﬁc Ocean use foraging grounds in the region of their natal beaches, a pattern we term natal foraging philopatry. Our ﬁndings conﬁrm that traditional views of natal homing solely for reproduction are incomplete and that many marine turtle species exhibit philopatry to natal areas to forage. Our results have important implications for life-history research and conservation of marine turtles and may extend to other wide-ranging marine vertebrates that demonstrate natal philopatry.

- by Didiher Chacon
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- Hawksbill Sea Turtle, Eastern Tropical Pacific

Management of species of conservation concern requires knowledge of demographic parameters, such as rates of recruitment, survival, and growth. In the Caribbean, hawksbill turtles (Eretmochelys imbricata) have been historically exploited in huge numbers to satisfy trade in their shells and meat. In the present study, we estimated growth rate of juvenile hawksbill turtles around Anegada, British Virgin Islands, using capture-mark-recapture of 59 turtles over periods of up to 649 days. Turtles were recaptured up to six times, having moved up to 5.9 km from the release location. Across all sizes, turtles grew at an average rate of 9.3 cm year(-1) (range 2.3-20.3 cm year(-1)), and gained mass at an average of 3.9 kg year(-1) (range 850 g-16.1 kg year(-1)). Carapace length was a significant predictor of growth rate and mass gain, but there was no relationship between either variable and sea surface temperature. These are among the fastest rates of growth reported for this species, with s...

- by Andrew McGowan
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- Conservation Biology, Conservation, Caribbean, Sex ratio

Sponges are an ecologically important component of modern Caribbean coral reefs.
However, little is known about the structure of sponge communities prior to the large-scale degradation
of Caribbean reef ecosystems. Here we explore changes in the sponge community over the
past millennium by analyzing the composition of sponge spicules from a sediment core collected
from a lagoonal reef within the archipelago of Bocas del Toro, Caribbean Panama. The analysis
reveals a change in spicule composition that began approximately 400 yr ago. During this time,
the share of monaxial spicules, belonging mostly to haplosclerid and axinellid sponges, decreased
while the relative number of spherical spicules, found typically in Placospongia, Geodia, and some
chondrillids, increased. These results were compared with previously published data on parrotfish,
corals, and reef accretion rates obtained from the same core. The increased share of spherical
spicules did not correlate with contemporaneous declines in the abundance of parrotfish (de -
termined from fish teeth) or with trends in the relative abundance of dominant coral species
(determined from coral skeletal remains) but was weakly correlated with reef accretion rates (de -
termined from sediment accumulation rates). Spicule morphogroup diversity and evenness
increased over the past ~400 yr, suggesting community changes were not due to reef environments
becoming less habitable for reef sponges. Although not tested directly, the increase in
spherical spicules may be due to declines in the abundance of sea turtles that preferentially feed
on sponges that contain these spicule types.

Mendonca, V.M., Al-Kiyumi, A.A., Al-Saady, S.M., Grobler, H.J., and Erzini, K.. 2001. Environment on the densest known nesting grounds of the critically endangered Hawksbill turtle Eretmochelys imbricata on the Dimaniyat Islands, Gulf of... more

- by Vanda M D Mendonca
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- Hawksbill Sea Turtle, Pandion haliaetus, Coral, Gulf of Oman

- by Karim Erzini
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- Conservation Biology, Hawksbill Sea Turtle, Dimaniyat Islands