Eretmochelys imbricata | UAE National Red List of Herpetofauna: Amphibians & Terrestrial Reptiles, Sea Snakes & Marine Turtles

Eretmochelys imbricata | (Linnaeus, 1766)
Countries in Assessment
United Arab Emirates
Country ISO code(s)
Does the assessment cover a marine EEZ area(s)?
Scope (Assessment)
Taxonomic Group
Taxonomic Group Level 2
Assessed taxon level
Taxonomic Notes
Genetic analyses in the Atlantic and Indo-Pacific indicate that nesting populations comprise separate and identifiable stocks that should be treated as separate management units (Bass et al. 1996, Bowen et al. 1996, Bowen and Karl 2007). Hawksbill aggregations on foraging grounds comprise animals from multiple nesting populations and often include animals from distant rookeries (Broderick et al. 1994, Bowen et al. 2007).
Taxon distribution as listed in assessment
This species is found throughout the territorial waters of the United Arab Emirates (<a href="""">OBIS-SEAMAP</a>; Halpin et al. 2009), although feeding areas are concentrated, based on a study of tracked post-nesting females, in central and western areas of the Arabian Gulf, with lesser numbers found in eastern parts of the Arabian Gulf and along the Gulf of Oman (Pilcher et al. 2014a). The species has been found to forage and nest along the mainland coast and on the islands of Abu Dhabi Emirate (Al-Ghais 2013, EAD 2016). The EOO, based on confirmed, active, nesting sites, is 30,351 km<sup>2</sup>.The extant sites known to support successful annual nesting attempts were used to estimate the AOO for this species, and are listed below;<ul><li> Abu Dhabi more than ten nesting sites with an average of 180 nests per year<u>Marawah Marine Biosphere Reserve</u>: 5-14 nests/year (Bu Tinah); &lt;5 nests/year (Jinanah).<u>Al Yasat Protected Area</u>: &gt;15 nests/year (Al Yasat Al Ulya); 5-15 nests/year (Um Al Hatab); &lt;5 nests/year (Ghaghah, Muhayyimat, Al Yasat Al Sufla).<u>Other islands</u>: &gt;15 nests/year (Zarkuh, Arzanah, Diyenah, Qarnen); 5-14 nests/year (Ghasha); &lt;5 nests/year (Um al Kurkum, Abu Al Abyad, Ras Ghanada, Saadiyat Island (but no successful nesting in 2017-2018)). No recent nesting recorded from Das Island.</li><li> Sharjah Sir Bu Na'ir (229 nests in 2018, with an annual average of c.300 per year (H. Das pers. comm. 2019).</li><li> Dubai Jebel Ali: 45 nests (in 2018) and increasing, however, this nesting beach is at high risk if work on Palm Jebel Ali recommences.</li></ul>The AOO, based on the known active nesting sites, is restricted, estimated at &gt;100 km<sup>2</sup> (assessment workshop data, and Abu Dhabi nesting site map via H. Das pers. comm. 2019.) using a 2 x 2 km grid (IUCN 2017), and whilst this may be an underestimate, the AOO will not exceed 500 km<sup>2</sup>. The species occurs in 9-11 locations, according to the IUCN Red List Guidelines (IUCN 2017), based on the currently known nesting sites and the threats that they face and the protected area management regimes within which they occur.A single nest was reported on the east coast at Khor Kalba in 2015 (Hebbelmann et al. 2016), probably by a turtle of Omani origin as there seems to be no movement between turtles from nesting sites in Oman and those in the Arabian Gulf (N. Pilcher pers. comm. 2018). Although significant given the rarity of nesting on the east coast of the UAE, this nest is excluded from the AOO estimate until repeated nesting occurs there.Within the Arabian Gulf, the species is known to nest on Saudi Arabian islands, at three minor sites in Kuwait, at a small number of sites in Iran, and on islands off the UAE (Pilcher et al. 2014a), and Qatar (c.200 Hawksbills nest annually at Fuwairit, Ras Laffan and Halul), with some additional sites known (Pilcher et al. 2015). The species undertakes summer northeasterly migrations into the deeper parts of the Gulf from July to August, followed by returns from September to October (Pilcher et al. 2014b). It is important to note that these migrations have been found to be a unique and adaptive behavioural response to high water temperatures in the Gulf during the summer months.The species has a circumglobal distribution throughout tropical and, to a lesser extent, subtropical waters of the Atlantic, Indian, and the Pacific oceans. However, Vargas (et al. 2015) found separation between populations inhabiting different oceans (Atlantic vs Indo-Pacific), as well as different clades within the Indo-Pacific region, one of which is defined by the Gulf subpopulation.Globally, Hawksbill nesting occurs in at least 70 countries, although much of it now only at low densities (Mortimer and Donnelly 2008, incl. Supplementary Material). Their movements within the marine environment are less understood, but Hawksbills are believed to inhabit coastal waters in more than 108 countries (Mortimer and Donnelly 2008).
Habitats and Ecology
Ecological system type
Terrestrial system
Freshwater system
Marine system
Habitat details as listed in assessment
Within the UAE the species uses sandy beaches for nesting. Whilst several of the nesting sites are within protected areas, they are often in near proximity to developed areas.No new nesting sites are likely due to extensive development.A four-year research project monitoring post-nesting Hawksbill turtles in the Gulf identified foraging habitats that were spread over vast areas but at the individual turtle level they typically ranged over only 40-60 km<sup>2</sup> with core areas of only 3-5 km<sup>2</sup> in size (Pilcher et al. 2014a). Based on the project ground-truthing surveys, the feeding areas were found to be limited to small reef mounds only a few 100s of metres across. In addition, the project revealed short-term migrations that were related to temporal climatic shifts during the summer months. The results indicate that Gulf Hawksbills employ thermoregulatory responses moving to northern and cooler areas during the summer. This type of behaviour is presumably taking them out of high temperature and potentially physiology-threatening conditions. Growth and reproduction are integrally linked to foraging ecology (Bjorndal 1997) and limitations to foraging or food availability can impact the productivity of individuals and populations. Similarly, exposure to temperatures which exceed normal tolerances can lead to a decrease in nutritional uptake and growth. Gulf turtles are amongst the smallest adult turtles worldwide, in comparison to Omani turtles which are an average of 10 cm larger in carapace length as nesting adults, suggesting that growth in Gulf turtles is nutrient-limited.Hawksbills mainly feed on corals, sponges and crustaceans. In the water, the species is reef-associated, and reefs are undergoing a continuing decline in extent and quality. In the western Arabian Gulf, the species was found using more fragmented feeding sites (and females were &lt;10 cm shorter than females from Oman).Hawksbills in the UAE may nest up to six times in a season with an average of three nests per turtle (Pilcher et al. 2014a), with 2-3 nests per female noted locally, however, recent genetic analysis found lower numbers of nests per female, at least in Dubai and Sir Bu Nair (A. Natoli pers. comm. 2018). The distribution of foraging habitat in the Gulf region has been described by Pilcher et al. (2014a) based on satellite tracking of 90 post-nesting female Hawksbills from nesting sites in Iran, Oman, Qatar and the UAE. In this study most of the turtles tagged in Qatar, Iran and the UAE migrated to southern and southwestern waters in the Gulf shared by the UAE and Qatar. A smaller number of turtles migrated northward towards Bahrain, Saudi Arabia, and Kuwait. Turtles spent 68% of the time in foraging grounds with home ranges of 40-“60 km<sup>2</sup> and small core areas of 6 km<sup>2</sup> were found to be larger than those used by Omani turtles (core areas ~3 km<sup>2</sup>). In addition, adult female turtles from the Arabian Gulf were significantly smaller than Omani turtles (by ~11 cm CCL). Arabian Gulf turtles spend an average of 20% of time undertaking summer migration loops, a thermoregulatory response to avoid elevated sea surface temperatures, as the Arabian Gulf regularly experiences sustained sea surface temperatures of over 30 '°C (Pilcher et al. 2014b).Genetic analyses revealed differences in mating behaviour between Sir Bu Na'air, Dubai and Abu Dhabi nesting sites, with a high level of single paternity in Dubai and Abu Dhabi nests and high multiple paternity in Sir Bu Na'air nests. Across the time of the study (2008 -2010) no females were detected to nest in more than one nesting site and males rarely sired at different nesting sites, further supporting the presence of different breeding grounds in UAE (Natoli et al. 2017).In the Arabian region, Hawksbill turtles deposit multiple clutches and nest during the short summer seasons, typically between April/May and July (Pilcher et al. 2014a).Hawksbills nest on insular and mainland sandy beaches throughout the tropics and subtropics. Newly emerged hatchlings enter the sea and are carried by offshore currents into major gyre systems where they remain until reaching a carapace length of some 20 to 30 cm (Mortimer and Donnelly 2008). However, recent studies (Vargas et al. 2015, Natoli et al. 2017) have found the species to have more distinct sub-populations, including a clade restricted to the Gulf. One in the sea, they move into foraging habitat that may comprise coral reefs or other hard bottom habitats, seagrass, algal beds, or mangrove bays and creeks (Musick and Limpus 1997) or mud flats. As they increase in size, immature turtles typically inhabit a series of habitats, with some tendency for larger turtles to inhabit deeper sites (van Dam and Diez 1997, Bowen et al. 2007). Once sexually mature, they undertake breeding migrations between foraging grounds and breeding areas at intervals of several years (Witzell 1983, Dobbs et al. 1999). Global population genetic studies have demonstrated the tendency of female sea turtles to return to breed at their natal rookery (Bowen and Karl 1997), even though as juveniles they may have foraged at developmental habitats located hundreds or thousands of kilometres from the natal beach. While Hawksbills undertake long migrations, some portion of immature animals may settle into foraging habitats near their beaches of origin (Bowen et al. 2007). Generation Length (from Mortimer and Donnelly 2008)Generation length is defined here as the age to maturity plus one half the reproductive longevity (Pianka 1974). Hawksbills mature very slowly, taking 20 to 40 years, and so are long-lived (Chaloupka and Musick 1997). Age to maturity in the Indo-Pacific requires a minimum of 30-35 years (Limpus 1992, Limpus and Miller 2000, Mortimer et al. 2002, 2003).Data on reproductive longevity in Hawksbills are limited, but becoming available with increasing numbers of intensively monitored, long-term projects on protected beaches. During the last decade, numerous individual Caribbean Hawksbills have been recorded actively nesting over a period of 14-22 years (Parrish and Goodman 2006). In the Indo-Pacific Mortimer and Bresson (1999) and Limpus (1992) have reported nesting over 17-20 years, comparable to other Chelonid turtles which range from 20 to 30 years (Carr et al. 1978, FitzSimmons et al. 1995).Given estimated ages to maturity of 25 years in the Caribbean and 35 years in the Indo-Pacific, with half of reproductive longevity estimated at ten years, a conservative generation length of 35 years (25 + 10 years) is calculated for the Caribbean and Western Atlantic, and 45 years (35 + 10 years) in the Indo-Pacific. In analyzing the data, declines over three generations are therefore measured for up to 135 years in the Indo-Pacific. In fact, generation length may well have been longer in the days when population density was higher (Bjorndal et al. 2000).
Is there a map available in assessment?
Assessed status
Asessment status in full
Assessment status abreviation
Assessment status criteria
B2ab(i,ii,iii,iv); D1
Assessment rationale/justification
This species is found throughout the territorial waters of the United Arab Emirates, although feeding areas are concentrated in the central and western areas of the Arabian Gulf, with very few found in eastern parts of the Arabian Gulf and along the Gulf of Oman. The species nests within the Arabian Gulf, and in the UAE nesting is primarily occurs on off-shore islands, although nesting also currently occurs on the mainland coast at Jebel Ali. A single recent occurrence at Khor Kalba on the east coast is excluded from the assessment until repeated annual nesting occurs. Some historical nesting sites, both on the islands and on the mainland, are no longer used. The extent of occurrence (EOO), based on known active nesting sites within the UAE exceeds 30,000 km<sup>2</sup>. The area of occupancy (AOO), based on the known nesting sites, is restricted, estimated at very much less than 500 km<sup>2</sup> using a 2 x 2 km grid (IUCN 2017). The species occurs in ten locations (with those within Marawah Marine Biosphere Reserve and the Al Yasat MPA considered a single location in each case), again based on the currently known nesting sites.With the currently available information, the species is assessed as Vulnerable (VU B2ab(i,ii,iii,iv); D1) on the basis of the restricted AOO and number of locations, with an observed continuing decline in the quality and extent of habitat, especially of nesting beaches, and an inferred continuing decline in the number of locations, with some sites not experiencing regular nesting activity (e.g., Al Siniyah) and others at risk (e.g., Jebel Ali). The species also qualifies as VU under criterion D1 given that there are estimated to be fewer than 1,000 mature individuals.Although natal homing imprecision means that some individuals originating outside the UAE may nest within the UAE, the potential rescue effect is not considered significant, and there is no regional adjustment to the assigned category.The ongoing conservation actions and research for this species within the UAE need to be maintained and expanded. In particular, monitoring and research are essential to the understanding of long-term future population trends, and actions are needed to protect nesting sites, especially those not currently within protected areas. This species should be reassessed for the UAE National Red List if new data become available on population size or trend, or on the impact of the known threats.Even though most currently-utilised nesting habitat for Hawksbill turtles is currently under some level of protection, we cannot assume that nesting and feeding habitats within Protected Areas are not at risk, as different activities with the potential to impact on the quality of these habitats may still take place within or near the boundaries of these areas. Therefore, monitoring and implementation of management plans should be exercised and assessed to infer the potential level of impact and risks to Hawksbill turtle populations, and to assess the efficacy of both management plans and protected area management for this species.The evidence of fine-scale population structure within the UAE and between the UAE and other nesting colonies in the Arabian Gulf provided by the study of Natoli et al. (2017) is relevant, even though based on a small sample size, as it provides an overall picture of the metapopulation dynamic for hawksbill turtles, where restricted gene flow between northern and southern areas of the Gulf, and between the inshore and offshore nesting colonies in the UAE, particularly Sir Bu Nair and Dubai nesting areas, exist. From these findings, one could infer that the known threats may have differential effects across subpopulations, and impacts may be particularly significant on those with a reduced number of nesters, as is the case of Dubai (the Jebel Ali nesting colony), with implications for the entire UAE subpopulation. As a result, future assessments would have to assess this impact carefully, and the species might well qualify for the Endangered category on the basis of actual or future declines in the numbers of mature individuals.
About the assessment
Assessment year
Assessors/contributors/reviewers listed
UAE National Red List Workshop
Affliation of assessor(s)/contributors/reviewers listed on assessment
Assessor affiliation specific
Criteria system
Criteria system specifics
IUCN v3.1 + Regional Guidelines v4.0
Criteria system used
Criteria Citation
IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1, Second edition. IUCN, Gland, Switzerland and Cambridge, UK. iv + 32pp pp. And IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN. iii + 41pp.
Endemic to region
Endemism Notes
Is an endemic?: Not_assigned
Threats listed in assessment
In the Arabian region, the impact of human activities remains largely unchecked and present the primary threat to Hawksbill turtles in UAE waters. The following threats have been described, with boat strike, fishing gear entanglement, marine debris ingestion, and nesting habitat destruction resulting from rapid coastal development representing the primary threats. Destruction of nesting habitat Coastlines in the UAE have undergone very rapid urban, industrial and tourism development, which has led to the destruction of nesting habitat, especially on the mainland. some island nesting sites have been less impacted, for example, those occurring within the Marawah Biosphere Reserve. Because Hawksbills prefer to nest under vegetation they are particularly impacted by beach-front development and the clearance of dune vegetation. Gas and oil refineries may seriously disrupt nesting habitat.Nesting habitat destruction has been rapid and extensive in the UAE, and has not yet ceased. For example, the Jebel Ali nesting site is likely to be severely impacted or lost if the development of Palm Jebel Ali recommences. Fisheries bycatch Hawksbills are particularly susceptible to entanglement in gill nets and capture on fishing hooks (Mortimer 1998). The full extent of the impact of fisheries bycatch on Hawksbill turtle populations is not yet well understood in the UAE. It is considered that increasing numbers of adults are stranding with evidence of drowning in fishing gear (Pilcher et al. 2008). Recent assessments in the Gulf region raise concerns about the potentially high impact that fisheries bycatch may have on turtles (83.6% of bycatch composition, representing ~4,726 captures year (Abdulqader et al. 2017). Boat strike, entanglement and ingestion of marine debris Ingestion of marine debris by Hawksbills is significant (White 2004). Recent research found that the majority of turtle strandings (including Hawksbill) in Abu Dhabi showed evidence of human interaction (boat strike 20% and entanglement 58%) (EAD 2016). Oil pollution There is evidence oil pollution has a greater impact on Hawksbills than on other species of turtle (Meylan and Redlow 2006). In some parts of the world (especially the Middle East) oil pollution is a major problem. Natural threats relevant to the UAE Hawksbill turtles are also subject to a range of natural threats. The Arabian Gulf undergoes extreme water and air temperature fluctuations, which present climate-related challenges to species diversity and distribution. Many smaller turtles strand in the Arabian Gulf from cold-stunning in the winter months (Pilcher et al. 2014b, 2015). Shell, egg and meat trade and consumption Despite listing of all Hawksbill populations on Appendix I of CITES since 1977, trade continued at high levels, with Japan continuing to import shell under a CITES reservation (exception) until 1993. Illegal trade continues, but there is no information on how this trade impacts the populations found in UAE waters. Intense levels of egg exploitation continue in many parts of the world., and adult and juvenile Hawksbills are still killed for meat in many areas, and in some areas turtle meat is used by fishermen as shark bait (J. Mortimer and C. Lagueux unpubl. data 2008). Again, there is no evidence of consumption in the UAE at present. Destruction of foraging habitat Hawksbills are typically associated with coral reefs, which are among the world's most endangered marine ecosystems. Climate change has led to massive coral bleaching events with permanent consequences for local habitats.In the Arabian Gulf, corals exist in a naturally extreme environment (Sheppard et al. 1992) at the absolute limit of their environmental tolerances (Riegl et al. 2011). Sea surface temperatures can fluctuate by more than &gt;20'°C over the course of a single year, with summer daily-mean temperatures of &gt;35'°C, while winter winds can chill water to &lt;12'°C (Sheppard et al. 1992, 2010). Corals in the Arabian Gulf also survive in a hypersaline environment year round with salinities regularly &gt;42 ppt (Sheppard et al. 1992) with significant seasonal insolation fluctuations (Sheppard et al. 2010). Partly as a result of these conditions, marine macrobenthos in the Arabian Gulf is limited in diversity and distribution (Basson et al. 1977, Al-Yamani et al. 2009). Corals in the Arabian Gulf are not only subject to natural stressors, but are also subject to increasing pressure from anthropogenic impacts such as overfishing, large-scale coastal development (Sheppard et al. 2010, Sale et al. 2011) and bleaching events as a result of human-induced climate change (Riegl et al. 2011).Coral reefs in the Arabian Gulf were severely affected by thermal bleaching in both 1996 and 1998 (Riegl 2002), and to a lesser extent in 2002 and 2010 (Foster et al. 2012), causing extensive loss of coral cover from patch reefs located along the coastline in the UAE (Riegl 1999, Sheppard and Loughland 2002). A shift in dominance towards faviids and poritids was also noted as well as spatial variation of coral communities with some areas showing low species richness (Burt et al. 2011). The loss of acroporid dominated communities and the shift to poritid and faviid dominated communities was reported by Bauman et al. (2012) to have occurred more widely than previously thought.The knock-on effect on other reef-dependent organisms is largely unknown, although Buchanan et al. (2015) identified 23 coral-dependent fishes of the Arabian Gulf and determined that, due to the limited area and degraded and fragmented nature of coral assemblages in the Arabian Gulf, all coral-dependent fishes were at elevated risk of extinction as defined by the IUCN Red List of Threatened Species' Categories and Criteria. Hybridisation and population constraints At certain sites where Hawksbill numbers are particularly low, they regularly hybridise with other species of sea turtles.A recent study (Natoli et al. 2017) raised concerns over the genetic viability of the UAE - and the wider Arabian Gulf - population of this species. The study found UAE individuals to have low genetic variability, with differences between populations both within the Arabian Gulf and between the Gulf and Indian Ocean populations, and that the Gulf population overall experienced a bottleneck/founder event. Predation Nest disturbance and the predation of eggs and young turtles by native and non-native (e.g., domestic dogs) is an unquantified threat but may be significant at some sites. For example, the single known nesting attempt on the east coast of the UAE was predated by an Arabian red fox (Hebbelmann et al. 2016).
Conservation Measures

Conservation measures:
Conservation measures notes:
Required conservation measures:

Scientific Name Kingdom Phylum Class Order Family Genus
Eretmochelys imbricata Animalia Chordata Reptilia Testudines Cheloniidae Eretmochelys