Marine Reptiles of the United Arab Emirates

Abstract

Within the waters of the United Arab Emirates (UAE), there are nine sea snake species and five species of sea turtles, two of which (Hawksbill and Green Sea Turtles) are breeding and forage residents and the remainder migrate to feed through UAE waters. Not only are the waters of the UAE recognized as important habitats for Hawksbill and Green Sea Turtles, but sea turtles are ambassador species for ocean conservation and recognized as a priority species by policy makers and conservationists alike. As a result, despite their numerous challenges, Hawksbill and Green turtle populations in the country are relatively stable. On the other hand, Loggerhead and Olive Ridley Sea Turtles, along with sea snakes enjoy far less interest and attention and so their threats, ecology and population status remain ambiguous. The known challenges facing marine reptiles in the UAE include, but are not limited to, habitat destruction through coastal development, marine pollution, bycatch and climate change.

1 Introduction

Marine reptiles are ectothermic (i.e. cold-blooded) and air-breathing species (see Fig. 19.1) found in tropical and subtropical waters, with the exception of one species which have feeding areas in colder Atlantic waters. Through several unique adaptations, marine reptiles can sustain life at sea, although some species retain ancestral terrestrial reproductive and physiologically-driven behaviors. With the exception of sea turtles, limited information is available on the ecology, behavior and habitat preference of other marine reptiles (Rasmussen et al. 2011; Fuentes et al. 2012). Present-day living (hereafter extant) species of marine reptiles include seven species of sea turtles, an estimated 62 species of sea snakes and one species of marine iguana subdivided into eleven sub-species. Within the waters of the UAE, there are five species of sea turtles, two of which are breeding residents and the remainder forage and migrate through UAE waters; as well as nine sea snake species.

Fig. 19.1

Green Sea Turtle, juvenile, taking a breath on the surface in the Gulf of Oman, UAE. Photo: Fadi Yaghmour

2 Sea Turtles

Sea turtles along with terrestrial tortoises and freshwater turtles are members of the Order Testudines. Sea turtles are distinguished from other turtles by their inability to retract their head into their shell, having streamlined hydrodynamic form, flattened paddle-like limbs (hereafter flippers) and they spend their entire life at sea with the exception of when they are nesting (Rasmussen et al. 2011; Fuentes et al. 2012; Manire et al. 2017). Their well-developed salt glands allow for the excretion of excess salts from the body. Sea turtle body sizes are much larger than freshwater turtles, allowing for gigantothermy—the ability to retain body temperature through reduced surface area to volume ratio (Manire et al. 2017; Paladino et al. 1990). The largest sea turtle species, Leatherback, is physiologically adapted for its pelagic habits and navigate cold, subpolar waters; and are able to dive to great depths for long periods of time (Bostrom et al. 2010).

2.1 Habits and Behavior of Sea Turtles

During nesting season, gravid female sea turtles emerge from the water to nest on sandy beaches, responding to a combination of physiological and environmental factors that in some cases influence mass nesting-events like those observed in Olive Ridley Sea Turtles (Lepidochelys olivacea). All sea turtle species chose particular sectors on the beach to nest, usually avoiding the portion of beaches that is reached by tides, and thus prone to erosion or inundation. The upper portion of beaches, where vegetation and dunes are present, is usually favored by Green Sea Turtles (Chelonia mydas) and Hawksbill Sea Turtles (Eretmochelys imbricata), while open sandy areas in the middle section are preferred by Olive Ridley Sea Turtles, Loggerhead Sea Turtles (Caretta caretta) and Leatherback Sea Turtles (Dermochelys coriacea), with the later found to nest closer to the water. Once the turtle has selected a suitable area, the nesting process starts by building a body pit and then digging a hole in the sand at an average depth of 35 cm to lay the eggs. Nest depth varies according to the species reaching depths up to 80–100 cm for Green and Leatherback Sea Turtles. After the turtle finishes laying her eggs, she covers and camouflages the nest with sand.

After about 2 months of in-nest incubation, the turtles begin hatching. Once hatched, turtles simultaneously dig out of the sand to reach the surface and emerge from their nest en masse. This behavior triggered by diel cycles rather than sand temperature (with turtles increasing digging activity at night) is thought to help avoid predators. Synchronous hatching of eggs in sea turtles has not yet been fully investigated and more experimental research is needed to clarify the physiological mechanisms and potential environmental cues involved. It is believed that the movements of each hatchling stimulate adjacent turtles to break out of their eggs. Other hypotheses suggest that CO₂ buildup on the nest can increase the metabolic rate of under-develop eggs facilitating synchronous hatching of eggs and some evidence points to vocalizations between eggs to also potentially play a part en masse hatching, as was demonstrated in other reptiles such as terrapins and crocodiles (Vergne and Mathevon 2008; Ferrara et al. 2013).

After hatching from their soft-shelled eggs, the hatchlings take 2–3 days to dig their way up to the surface of the nesting beach. There, the hatchlings rapidly crawl towards the ocean, which is brightened by the reflection of the stars and moon, allowing individuals to visually orient towards the sea. However, in developed coastal areas, artificial lighting can confuse and disorient these hatchlings from finding the ocean (see Chap. 23; Tuxbury and Salmon 2005). On their journey across the beach, these hatchlings are exposed to predators such as ghost crabs and seabirds. Once in the water, hatchlings begin to swim swiftly to avoid predators at sea, such as large fish and birds (Witherington and Salmon 1992). During this swimming frenzy, turtles do not feed and live from the yolk reserve they hold. Those hatchlings that succeed in moving further out to sea will decrease their swimming activity or swimming frenzy and spend their first years adrift feeding in the safety of the open-ocean in what is known as the pelagic stage of their life cycle.

As these juveniles continue to grow, they migrate to inshore habitats such as estuaries and reefs where they remain until mature. Mature sea turtles will then begin long-distance reproductive migrations, with females returning to the area on the beaches where they hatched, which they locate using olfactory cues, chemical imprinting and the earth’s magnetic field.

2.2 Diversity of Sea Turtles in the UAE

Historically, there were four families of sea turtles during the Cretaceous period (145–65 million years ago), which diversified later into the ancestors of both the land and sea turtles. Today, only two extant families of sea turtles occur in the world’s ocean: the hard-shelled sea turtles (Cheloniidae) and the leathery-shelled sea turtles (Dermochelyidae). The leathery-shelled sea turtles are distinguished from the hard-shelled sea turtles by having a smooth skin resembling fine leather with spikes on the top-shell (hereafter carapace). The hard-shelled sea turtles (Fig. 19.2) consists of six extant species of turtles: Flatback (Natator depressus), Green, Hawksbill, Loggerhead, Kemp’s Ridley (Lepidochelys kempii), and Olive Ridley. The Dermochelyidae family consists of only one turtle species, the Leatherback. Of these seven marine turtle species, five have been recorded in UAE waters: Green, Hawksbill, Loggerhead, Olive Ridley and Leatherback Sea Turtles (Rasmussen et al. 2011; Fuentes et al. 2012; Manire et al. 2017).

Fig. 19.2

Key to hard-shell sea turtles of the UAE. Green Sea Turtle (a); Hawksbill Sea Turtle (b); Loggerhead Sea Turtle (c); Olive Ridley Sea Turtle (d). Photos: Fadi Yaghmour

2.2.1 Hawksbill Sea Turtle (Eretmochelys imbricata)

Named for their prominent curved bird-like beaks, Hawksbill Sea Turtles are medium-sized and are distinguished from other species by their long necks, two pairs of prefrontal scutes (scales) between their eyes, an oval carapace with four lateral scutes, pointed saw-like margins and overlapping scutes bearing striking colors (Manire et al. 2017). The coloration of these scutes is golden brown with appealing streaks of red, orange, black and brown. These attractive colors has proven a costly attribute for Hawksbill Sea Turtles, as it has caused them to be the target of unsustainable levels of hunting for centuries for the creation of ‘bekko’, accessories and ornaments made from its carapace scutes. Bekko includes a variety of items ranging from guitar picks, hair ornaments, jewelry and other luxury items. Though bekko was perhaps not in high demand locally, it was used to make clips, known as ‘fettam’, that helped keep pearl divers’ nostrils closed while underwater. As a result of the demand for bekko, along with other threats, Hawksbill Sea Turtle populations have suffered massive declines worldwide, estimated at approximately 90% loss over the last century; they are now the only species of sea turtle listed as Critically Endangered (CE) by the International Union for Conservation of Nature (IUCN) (Mortimer and Donnelly 2008).

Before the 1980s, Hawksbill Sea Turtles were commonly exploited in the UAE and the wider northwestern Indian Ocean for their carapace, meat and eggs (Hirth and Abdel Latif 1980; Aspinall 1995). Current laws such as UAE Federal Law No. (23) of the year 1999 concerning the exploitation, protection and development of living marine resources has long since banned and phased out the common practice of Hawksbill Sea Turtle exploitation in the UAE. However, regional countries including Bahrain, Djibouti, Egypt, Eritrea, Iran, Oman, Qatar, Saudi Arabia, Somalia Sudan and Yemen do report continued but decreasing exploitation of turtle eggs, meat, and carapace (Pilcher and Al-Merghani 2000; Gladstone et al. 2003; PERSGA 2006; Pilcher and Saad 2006; Rees and Baker 2006; Van de Elst 2006; Ficetola 2008; Al Ameri et al. 2020).

In the UAE, Hawksbill Sea Turtles are the second most common species of sea turtle after Green Turtles (see below), and they are also considered the primary nesting species (Fig. 19.3). Hawksbill nesting is confined to the Arabian Gulf coast of the UAE, where they are known to nest on numerous islands and mainland beaches in the territorial waters of Dubai, Abu Dhabi and Sharjah (Pilcher et al. 2014). There their nesting occurs in small assemblages in habitats that include sandy beaches as well as rocky, coarse-sand beaches. It is estimated that ca. 500 females/year nest in the UAE (Ameri et al. 2022), which is comparable to Saudi Arabia, and below key sites in Iran and Oman where larger numbers are reported (~1000 females/year) (Mobaraki 2004; Ross and Barwani 1982). Recent genetic population analyses indicate that turtles across the UAE exhibit low genetic diversity and belong to the same Gulf population management unit, which are distinct from the Indian Ocean populations (Natoli et al. 2017), highlighting the importance of conservation actions. The Hawksbill Sea Turtle nesting season in the region is short (3 months) compared to other geographic regions, where it can extend up to 6 to 12 months. In the UAE the start of the nesting season has been reported in some areas as early as March (Rodriguez-Zarate, unpubl. data) extending up to June.

Fig. 19.3

Hawksbill Sea Turtle nesting in Sir Bu Nair Protected Area, Sharjah. Photo: Clara Jimena Rodriguez-Zarate

When turtles crawl up the beach to nest they leave a mark or track behind in the sand. Such tracks are distinctive among species by their shape and size, allowing the identification of a turtle species when the animal is not directly observed on the beach. Hawksbill Turtle tracks are asymmetrical in shape, showing alternated diagonal marks left by the simultaneous forward movement of the frontal flippers, accompanied by a serpent central drag-mark from the tail. Hawksbill tracks usually have a width of 65–85 cm. Arabian populations of hawksbill turtles lay 80 to 130 eggs per clutch, and are known to nest more than once within a season, often laying up to 2–3 clutches of eggs per season. Genetic parenting analyses provided evidence of multiple paternity in Hawksbill Sea Turtles only in the nesting area of Sir Bu Nair (Natoli et al. 2017); a phenomenon that has been widely documented for marine turtles worldwide. The incubation period for eggs extends to between 50 to 61 days. However, local variation of these reproductive parameters have not been fully described across nesting areas for Hawksbill Sea Turtles in the UAE. Conversely, the east coast of the UAE on the Gulf of Oman has few and intermittent contemporary records of Hawksbill Sea Turtle nesting activity (Hebbelmann et al. 2016; Yaghmour and Jarwan 2020).

As omnivores, Hawksbill Sea Turtles have a varied diet. Young Hawksbills feed in oceanic waters on planktonic animals including hydroids and floating insects. Juvenile Hawksbills then migrate to shallow coastal habitats such as coral reefs and seagrass meadows to feed on sea cucumbers, anemones, mollusks, cnidarians, algae and sponges. As the turtles mature, sponges comprise an increasingly prominent proportion of their diet. There are no studies investigating the diet of Hawksbill Sea Turtles in the UAE, however, unpublished observations made of gut contents of stranded Hawksbill Sea Turtles from Sharjah include fish bones, sponges, cephalopod beaks, mollusk shells and insects; items comparable to reports from other areas (Yaghmour, unpubl. data).

Further details on Hawksbill feeding activities were reported in an investigation of post-nesting migrations of Hawksbills in Arabian waters. It was found that in the Arabian Gulf, Hawksbills spent approximately 70% of their time occupying discreet foraging grounds. The majority of the foraging grounds in the Arabian Gulf were small reef mounds within seagrass meadows located in the waters of Abu Dhabi and southern Qatar. Hawksbill Sea Turtles were observed to leave these habitats for 2–3 months during their summer migrations to escape the increasing temperatures of surface water (Pilcher et al. 2014). Comparatively, Hawksbill Sea Turtles in the cooler waters of the Gulf of Oman spent up to 83% of their time in foraging grounds in the waters of Oman. The discrepancy in time spent in foraging areas is a result of summer migration only occurring in Arabian Gulf dwelling Hawksbill Sea Turtles.

2.2.2 Green Sea Turtle (Chelonia mydas)

Known locally as ‘hamas’ or ‘shiree’, Green Sea Turtles (see Fig. 19.1) are distinguished from other sea turtles by having only one pair of prefrontal scutes between their eyes, four lateral scutes on their carapace and a blunt beak that consists of tomia (serrations used for cutting into seagrass and algae). Globally, they are the largest of the hard-shelled sea turtle species and the second largest extant species of sea turtle. Contrary to popular belief, the outer body color of Green Sea Turtles are not green, but their name is derived from the greenish color of their cartilage and fat. The coloration of their carapace is olive-gray or brown with streaks and splatters of black or dark brown, while the dorsal surface of their head and flippers is covered by dark scales with lighter seams.

Green Sea Turtle hatchlings and juveniles are omnivores, feeding in oceanic waters on floating algae, inclusive of the variety of associated organisms such as amphipods, bryozoans, tubeworms, marine insects and mollusks. As they grow older, immature turtles undergo developmental shifts and return to nearshore coastal habitats such as mangroves, seagrass meadows and coral reefs. Immature turtles are considered omnivorous, though they heavily favor macroalgae and seagrass, while adults are considered strict herbivores which rarely ingest animals; typically incidentally while feeding on seagrass or algae.

Green Sea Turtles in the UAE consist of a mixture of juveniles, subadults and adults feeding in foraging grounds, with adults seasonally migrating out to mating grounds. Foraging grounds include seagrass beds, primarily of Narrowleaf grass (Halodule uninervis) and Spoon grass (Halophila ovalis), or mixed-bottoms composed of mangroves and coral reefs close to sea grass or algal beds (see Chap. 9). In the UAE, the largest foraging grounds occur on the extensive seagrass beds of western Abu Dhabi, although they also occur in lagoons and other sheltered areas across the emirates (see Chap. 8). While juveniles favor these habitats as they mature to adulthood, adults utilize these resources when foraging between reproductive periods (Musick and Limpus 1997). Studies investigating the gut contents of Green Sea Turtles from the Gulf of Oman suggest that the diet consists mostly of seagrasses (Halophila uninervis, H. ovalis and H. ovata) and algae (Lychaete herpestica. Nizamudinnia zanardinii, Chaetomorpha aerea and Sargassum illicifolium) (Ross 1985; Ferreira et al. 2006).

The migratory patterns of adult Green Sea Turtles in the UAE has also been investigated in recent studies. These studies suggest that adult Green Sea Turtles remain close to shore while undertaking reproductive migrations from feeding areas in the UAE, mainly in the southwestern Gulf basin in Abu Dhabi waters, to nesting areas located in Oman, moving in a narrow corridor of approximately 10-20 km off the coast (Pilcher et al. 2020). In this study few turtles ventured to deeper waters during their migration or performed migration loops into the Indian Ocean en route to nesting beaches; these route selections are not yet fully understood. Similar habitat-use patterns were reported by Rees et al. (2012) for post-nesting Green Sea Turtles in Oman.

Despite being the most common turtle species in the UAE, Green Sea Turtle nesting sites are considered rare and sporadic. On Sir Bu Nair island (Sharjah) the successful nesting of two Green Sea Turtles was corroborated by the observation of hatchlings and exhumation of their nest in 2010 (EPAA 2012). Unsuccessful nesting attempts were identified by tracks left on the sand by the turtles and sporadically a few are still reported today at this location (Rodriguez-Zarate, unpubl. data). Unlike Hawksbill Sea Turtles, Green Sea Turtles have a symmetrical sand track consisting of deeply cut and symmetrical diagonal marks made by the front flippers and a straight center drag mark from the tail. Being larger in size compared to Hawksbill Sea Turtles, Green Sea Turtle tracks are wider, typically 85–130 cm. Green Sea Turtles lay 80 to 120 eggs per clutch and are known to nest more than one time within the same nesting season, ranging from two to four clutches. The incubation period is between 60 to 65 days. Major nesting rookeries of Green Sea Turtles in the Arabian region are located in Ras al Hadd (Oman) (~20,000 Green Sea Turtles nest annually (Ross and Barwani 1982)) and Sharma-Jethmoun area (Yemen) where over 27,000 turtles nested in 2014 (Nasher and Al Jumaily 2013). Relatively large nesting aggregations (~1000 nesting females/year) are also found at Karan and Jana islands (Arabian Gulf coast, Saudi Arabia) (Pilcher 2000).

2.2.3 Loggerhead Sea Turtle (Caretta caretta)

Known locally as ‘murah’, Loggerhead Sea Turtles are distinguished from other turtle species by their disproportionately large head. They have two pairs of prefrontal scutes between their eyes and a heart shaped, mahogany to red-brown colored carapace with five lateral scutes. As adults, Loggerhead Sea Turtles are smaller than Green Sea Turtles but much larger than Hawksbills. They are rarely observed along the UAE’s Arabian Gulf coast but are frequently observed in the Gulf of Oman coast, due to its proximity to Masirah island in Oman. Island beaches are important nesting habitats for the critically endangered Northwest Indian Ocean subpopulation of Loggerhead Sea Turtles and it is known to be among the most important Loggerhead Sea Turtle rookeries in the world. To date, no Loggerhead nesting has been recorded in the UAE.

Loggerhead Sea Turtles are carnivorous bottom feeders, which search the deeper waters of the continental shelf for crustaceans, gastropods, jellyfish along with other sessile or slow-moving prey (Wallace et al. 2009). Across the region, limited information exists of this species feeding ecology, however, unpublished observations made of gut contents of stranded Loggerhead Sea Turtles from the waters along Sharjah’s East coast included Sea Urchin (Diadema setosum), Sea Cucumber (Holothuria scabra), Sand Dollar (Echinodiscus auritus), gastropods consisting mostly of False Venus (Murex scolopax), cuttlefishes, fishes, bivalves and crabs (F. Yaghmour, unpubl. data). In addition to being an important part of their diet, evidence exists that the Columbus Crab coexist symbiotically with Loggerhead Sea Turtles in the UAE (Yaghmour and Al Naqbi 2020; see Box 19.1).

Box 19.1 Loggerhead Sea Turtles and Their Relationship with Columbus Crabs

A study by Yaghmour and Al Naqbi (2020) revealed that some Loggerhead Sea Turtles in the UAE are associated with Columbus Crab (Planes minutus) (Fig. 19.4). This crab is often observed on the tail or hind flippers of Loggerhead Sea Turtles and are believed to ingest the excrement of their host. This relationship would be known as ‘commensalism’ as one species benefits (the crab) while the other is unaffected (the turtle). However, other studies suggest that they might also clean the host turtle’s carapace by feeding on the sessile epibiota on its surface (Crane 1937; Frick et al. 2004). In this case, as both the crab and the turtle would benefit (food for the crab, less energy-taxing swimming for the turtle) the relationship would be defined as ‘mutualism’.

Fig. 19.4

Columbus Crab. Photo: Fadi Yaghmour

Further details on the habits of Loggerhead Sea Turtles were revealed through satellite tracking to identify feeding grounds and which areas are frequently used. Satellite trackers attached to post-nesting Loggerhead Sea Turtles in Masirah island (Oman) revealed extensive post-nesting movements. Turtles foraged in the oceanic zone for the majority of their time (76%) but also used shallow coastal shelf habitats. This data supports the theorizing of behavioral plasticity and a bimodal foraging strategy where turtles move between 400 km to 1400 km offshore from Oman and Yemen (Rees et al. 2010, 2018). This bimodal feeding strategy was also reported in studies of other Loggerhead populations (McClellan et al. 2010) where individuals in the coastal shelf remain as benthic feeders, while oceanic individuals feed opportunistically in open waters on mid-water organisms such as jellyfish or crustaceans (McClellan et al. 2010; Frick et al. 2004).

2.2.4 Olive Ridley Sea Turtle (Lepidochelys olivacea)

The smallest of the UAE’s marine turtles, Olive Ridley Sea Turtles are distinguished from other species in the region by their nearly circular carapace, which can measure equal in length and width. Their carapace also carries at least six lateral scutes and the inframarginal scutes on their plastron (bottom-shell) bear pores, a characteristic unique to the Olive Ridley Sea Turtle and Kemp’s Ridley Sea (Lepidochelys kempii). Olive Ridley Sea Turtles are predominantly carnivorous, feeding on salps, mollusks, crustaceans, bryozoans and on algae in oceanic waters and coastal waters. There are no studies investigating the diets of Olive Ridley Sea Turtles in the UAE, although unpublished observations made of gut contents of stranded Olive Ridley Sea Turtles from Sharjah include macroalgae, fish, cephalopod beaks and insects (F. Yaghmour, unpubl. data).

In the region, Olive Ridley Sea Turtles have been observed in the waters of Pakistan, India, Iran, Oman and UAE (Abreu-Grobois and Plotkin 2008). Olive Ridley Sea Turtles are known to nest on Masirah island located in the Gulf of Oman (Rees et al. 2012) but satellite tracking data suggests they swim north to settle along the East coast of the UAE during post-nesting migrations (Rees et al. 2012).

Little is known about the ecology of this species in the Arabian Gulf. Olive Ridley Sea Turtles were first recorded in the Arabian Gulf along the coastal waters of Kuwait in 2003 by Bishop et al. (2007). Since then there have been records in Iran (Qeshm Island, Larak island, Bushehr town, Kharg island), Bahrain (Rees et al. 2012) and the UAE (Yaghmour 2019a). To date there is only a single record of an Olive Ridley Sea Turtle nesting in the Arabian Gulf, which was recorded in 2013 at the Nayband Marine-Coastal National Park, Iran. In the UAE, an Olive Ridley Sea Turtle nest was reported on the beach of Khor Kalba, Sharjah in 2021 (Yaghmour and Rodríguez-Zárate 2021).

2.2.5 Leatherback Sea Turtle (Dermochelys coriacea)

Weighing up to 1000 Kg and measuring up to 3 meters in length, Leatherbacks are the largest among marine reptiles. They are also easily distinguished from any other turtle species due to the lack of a hard carapace with scutes; instead their teardrop shaped carapace has a fleshy surface with seven longitudinal ridges known as keels. The coloration of their dorsal surface is black to dark-gray with light-gray spatters. Their beak sheaths are relatively weak and specially adapted for consuming gelatinous prey. At all stages of their life, Leatherbacks will primarily consume gelatinous marine animals including hydroids, medusae, salps and primosomes. Information on Leatherback Sea Turtles in Arabian waters is limited to sporadic observations and through strandings in UAE waters during the past few decades. In the UAE, Leatherbacks have been reported from the coasts of Dubai, Khor Kalba and Fujairah ( Gardner 2013; Buzás et al. 2018).

3 Sea Snakes

Restricted to life at sea, ‘true’ sea snakes are members of the Order Squamata from the family Elapidae (subfamily Hydrophiinae) and are the most widely distributed group of marine snakes. With the exception of the Yellow-bellied Sea Snake, the collective range of sea snakes extends along the coastal waters from the Arabian Gulf eastwards into the tropical waters of Asia and Australia, through to the islands of southwestern Pacific and northward to Japan and China (Heatwole 1999; Sindaco et al. 2013). The habitats which sea snakes can occupy is limited by ocean temperatures thus their global distribution is restricted to the broad continental shelves of warm tropical and subtropical waters. Sea snakes, although they are solely restricted to a marine environment (see Box 19.2), share several similarities with terrestrial snakes in that they are air-breathing, the body is covered with scales, and they have a forked tongue, lidless eyes and no limbs. Sea snakes range in size from half a meter to one meter in length depending on the species, with exceptions such as the Yellow Sea Snake which can reach lengths of up to 2.75 meters in parts of its distribution range (Minton 1975; Heatwole 1999; Gardner 2013). Sea snakes are venomous and through their short hollow fangs positioned on both sides of the upper jaw towards the front (proteroglyphous), they can deliver neurotoxins to subdue large prey. Sea snakes can be a difficult group to identify as several species appear morphologically similar and they may vary in coloration and pattern during different life stages.

3.1 Habits and Behavior of Sea Snakes

Among marine reptiles, sea snakes are the most understudied group with research limited to a handful of species of which the majority of the species studied to date are those within Australian waters. With the exception of documenting species diversity within the waters of the UAE, there are limited studies focusing on elements of their natural history. Habits and behaviors of the species covered by this chapter are concluded from observations from other parts of their range, along with anecdotal observations to provide baseline information.

Sea snakes appear not to be territorial, with home ranges overlapping among individuals of the same species (Heatwole 1999). Territorial defensive behavior has not been observed and is not known among the several species occurring within the waters of the UAE. Sexual dimorphism (i.e. different appearance between males and females) varies between species, but this is largely subjected to the availability of data among the different species. Depending on the species, some may have larger females than males, similar to what is often observed in terrestrial snakes, or males larger than females, while within some species there are no size differences between the species (Heatwole 1999; de Silva et al. 2011a, b; Buzás et al. 2018). Among those where sexual dimorphism exists, a difference in the number and character of scales may be observed. As an example, among the Arabian Gulf Sea Snake (Hydrophis lapemoides) sexual dimorphism can be noted between reproductive mature males and females, with males having prominent enlarge keeled dorsal scales.

Reproduction among sea snakes is similar to terrestrial snakes. The male has two copulatory organs, called hemipenes, which are located on either side of the base of the tail behind the cloaca vent. The hemipene has spike and hook-like structures which aids it to keep in place during mating. Mating may be sustained over several breathing cycles, with the female controlling the breathing rhythm, while the male must breathe air at the same time the female surface (Heatwole 1999). The timing of breeding of most sea snake species is not well understood and varies between regions. All true sea snakes are viviparous (live-bearing) and young are positioned forward in the body in comparison to terrestrial snakes, to reduce interference with swimming movements. Gestation periods can vary greatly between species, ranging from 3 to 4 months, or up to 11 months for species such as the Beaked Sea Snake (Heatwole 1999). The gestation period of females for each species may influence the period between breeding, with those with longer gestation periods having an intervening non-breeding season to replenish energy reserves.

It has been suggested that pregnant females may resort, en masse, to protected bays to give birth to their young (Dunson 1975). A female will give birth to the young underwater and shortly after the newborns surface for their first breath. Litter sizes vary between species and it depends on the size of the individual female. The Arabian Gulf Sea Snake has larger young and small litter sizes in comparison with much larger Beaked Sea Snake which can have a litter size of up to 18 young (Heatwole 1999; de Silva et al. 2011a, b). There is no parental care of the young by the female. Limited information on the growth rate of sea snakes are available, most appear to have a rapid growth rate until sexual maturity. Sexual maturity in some species such as the Beaked Sea Snake varies from 1.5 years for males and 1.5–2 years for females (Heatwole 1999), but this may vary between different regions across their distribution range. Typically, in the same manner terrestrial snakes shed their skin (ecdysis), sea snakes shed their skin throughout their lifetime. The frequency between ecdysis will be higher in younger individuals and decrease as they mature. Ecdysis may also further aid in controlling external parasites and other organisms which were attached to the skin (Zann 1975).

Sea snakes are diurnal, nocturnal or both, varying between species, and this may be influenced by temperature fluctuations during the seasons. Irrelevant to their preferred activity periods, they must surface to breath. Sea snakes predominantly feed on fish (piscivorous) and based on their diet preferences they are often grouped into either specialist or generalist categories. It is dietary specialization which was suggested as the reason for unique body shapes and sizes among sea snake species (Sherratt et al. 2018).

3.2 Diversity of Sea Snakes

Among the monophyletic assemblage of the estimated 62 species of sea snakes (Sanders et al. 2012) the highest diversity of species is found in northern Australia, Malaysia and the Indonesian archipelago. Species richness decreases towards the Arabian Sea with 10 species recorded in the Arabian Gulf and the Gulf of Oman (Egan 2007; Gardner 2013; Rezaie-Atagholipour et al. 2016; Carranza et al. 2021; Chowdhury et al. 2021). The 10 species in the Arabian Gulf represent the westernmost limit of this group of sea snakes, with the exception of the Yellow-bellied Sea Snake, which reaches the eastern coast of Africa. Within the territorial waters of the UAE, nine species have been recorded (Gasperetti 1988; Soorae et al. 2006; Gardner 2013; Buzás et al. 2018). Three of the species are abundant, five are rarely encountered and one is known from a single specimen. Beaked Sea Snakes are known from only a few specimens, of which most are from strandings. The Viperine Sea Snake from the Arabian Gulf is known from a single museum specimen collected from near Sir Bu Nair (alt. spelling: Sir Abu Nu’ayr), by the crew of the HMS Dalrymple (British Royal Navy) around 1963 (Gasperetti 1988). Sea snakes may be rare or overlooked during surveys, thus the known recorded species for the UAE should be considered the minimal number of species (see Box 19.2).

Box 19.2 Sea Snake Adaptations for Life at Sea

Sea snakes have developed several adaptations for life in a marine environment. To facilitate swimming, sea snakes have laterally compressed bodies (in comparison with the cylindrical bodies of their terrestrial snake relatives) with paddle-like tails. The ventral (i.e. belly) scales of sea snakes are reduced in size, as they no longer require land movement and are of little benefit for swimming; this is one reason why sea snakes cannot freely move on land.

Sea snakes have an enlarged lung which allows for increased air supply and improved oxygen supply into the blood. The lung further aids in buoyancy control to facilitate movement in the water while diving or surfacing for air. Respiration through the skin (cutaneous respiration) allows the absorption of oxygen and elimination of carbon dioxide, which combined with the saccular lung increase diving capacity (Heatwole 1999). Apart from respiration, the skin allows water through but resists the inward flow of salts.

The eyes of sea snakes, in comparison with terrestrial snakes, have changes in the visual pigments which improves vision under water and combined with their well-developed olfactory capability can help locate prey (Kutsuma et al. 2018). The nostrils of sea snakes are positioned upwards and regulated by valves to keep air in and avoid seawater from entering. They have a sublingual gland (modified salivary gland) in the mouth, located under the tongue sheath and which empties salt brine. The salt brine is expelled when the tongue protrudes.

Despite these adaptations to survive in a marine environment, sea snakes can dehydrate and infrequently still require freshwater. Freshwater is consumed when it rains and, on calm seas, a layer of freshwater may float on the heavier seawater which provides an additional source. The patchiness of sea snakes at different spatial scales might be related to the spatiotemporal distribution of rainfall (Lillywhite et al. 2012).

3.2.1 Arabian Gulf Sea Snake (Hydrophis lapemoides)

A smaller species, which reach lengths of up to 96 centimeters. The dorsal color between different snakes can be highly variable ranging from light brown or yellowish with dark bars across the dorsal surface (Fig. 19.5). Youngsters are light gray or yellow with prominent thick black bars across the body (Fig. 19.6). The Arabian Gulf Sea Snake is widely distributed from the Malay Archipelago westwards into the Gulf of Oman and Arabian Gulf (Sindaco et al. 2013; Ganesh et al. 2019; Chowdhury et al. 2021). It is abundant in the Arabian Gulf and Gulf of Oman. It prefers shallow marine waters and is often encountered near to the shore. They feed on small fish such as gobies and eels. Regularly encountered during the day and after dusk. Females will give birth (viviparity) to 1–5 young.

Fig. 19.5

Arabian Gulf Sea Snake, adult, female, from the Arabian Gulf, UAE. Photo: Johannes Els

Fig. 19.6

Arabian Gulf Sea Snake, youngster, from the Arabian Gulf, UAE, to illustrate the variability in color and patterns observed during different life stages. Photo: Johannes Els

3.2.2 Ornate Reef Sea Snake (Hydrophis ornatus)

A medium-sized species which reach lengths of up to 1.2 meters. Variable in color, the dorsal (i.e. back) is light brown or yellowish with dark bars or oval-rhomboidal spots close to each other (Fig. 19.7). The Ornate Reef Sea Snake is widely distributed from northern Australia westwards into the Gulf of Oman and Arabian Gulf (Bauer and Sadlier 2000; Cogger 2000; Jongbloed 2000, Kanta et al. 2021). The species is abundant in the Arabian Gulf and Gulf of Oman. It is often found in coastal waters during the day and after dusk. They eat a variety of fish species. Females will give birth to 2–5 young.

Fig. 19.7

An adult Ornate Reef Sea Snake stranded on a beach along the Arabian Gulf, UAE. Photo: Johannes Els

3.2.3 Yellow-Bellied Sea Snake (Hydrophis platurus)

A smaller species in comparison with the Arabian Gulf Sea Snake, reaching a total length of 88 centimeters. The Yellow-bellied Sea Snake is visibly distinct from all other species with a dark brown or black dorsal with a dark- or light-yellow ventral and flanks. The tail has vertical bands and blotches on a whitish background. The head is distinct from the body with a very narrow elongated snout. Rarely, other color variations are observed such as one melanistic Yellow-bellied Sea Snake found stranded on Saadiyat Beach, Abu Dhabi on the 21st of October 2022. (Fig. 19.8). Melanism is characterized by the excessive development of the dark-colored pigment melanin.

Fig. 19.8

Typical Yellow-bellied Sea Snake (Left; Photo: Johannes Els); Melanistic Yellow-bellied Sea Snake found stranded on Saadiyat Beach, Abu Dhabi on October 2022. (Right; Photo: Nick Cochrane-Dyet)

Yellow-bellied Sea Snakes are the most widely distributed species of all sea snakes, extending from the western shores of America, across the Pacific and Indian Oceans entering the Gulf of Oman and Arabian Gulf, and further westwards along the eastern coastline of Africa. It is abundant in the Gulf of Oman and often prefers clear, shallow waters with weak surf and currents. It is a pelagic species and has been observed to aggregate in large numbers of up to 1000 individuals per hectare on marine slicks. These aggregations are not related to breeding, but feeding gatherings and it is suggested that it may help individuals to increase their feeding opportunity due to fishes seeking shelter beneath the floating debris (Kropach 1971; Lillywhite et al. 2010). Yellow-bellied Sea Snakes predate on a variety of fish species (Fig. 19.9). Females give birth to 1–6 young.

Fig. 19.9

Yellow-bellied Sea Snake feeding on a fish, Gulf of Oman, UAE. Photo: Johannes Els

3.2.4 Graceful Small-Headed Sea Snake (Hydrophis gracilis)

A medium-sized species reaching lengths of just over 1 m. It is distinguishable from all other species by having a small pointed head, a slender anterior body which thickens posteriorly four or five times in diameter compared to the neck. The species vary in color from light gray dorsally and paler on the ventral side which darkens posteriorly. Dark broad dorsal bands on the dorsal side of the anterior part of the body. It is widely distributed from northern Australia and New Guinea westwards to the Gulf of Oman and Arabian Gulf (Volsøe 1939; Sindaco et al. 2013; Rezaie-Atagholipour et al. 2016). In the Arabian Gulf and Gulf of Oman the species appear to prefer coastal water and is rarely encountered. Graceful Small-headed Sea Snakes are specialists, feeding on slender bottom dwelling fish species such as gobies and eels that are hunted from within their burrows. Females give birth to 1–16 young.

3.2.5 Yellow Sea Snake (Hydrophis spiralis)

The largest sized species in Arabia, reaching a length of 2.75 meters. The dorsal color is yellow or brownish with narrow black rings encircling the body, which are narrower than the yellowish interspaces (Fig. 19.10). The head is yellow and the tail tip is usually black. Yellow Sea Snakes are widely distributed from New Caledonia westwards to the Gulf of Oman and Arabian Gulf (Volsøe 1939; Sindaco et al. 2013). Within the Arabian Gulf and Gulf of Oman, the species is less abundant in comparison with the Arabian Gulf Sea Snake or Ornate Reef Sea Snake. It prefers shallow coastal waters and has been found on the sea surface during the day and after dusk. Yellow Sea Snakes feed mainly on eels and other slender fish species. Females give birth to 5–14 young.

Fig. 19.10

Yellow Sea Snake, adult, from the Gulf of Oman, UAE. Photo: Fadi Yaghmour

3.2.6 Spine-Bellied Sea Snake (Hydrophis curtus)

A medium-sized species reaching a length of 1 m. It has a large, robust, blunt head that is not distinct from the neck. Body scales each have a single sharp keel in the middle and the keels increases in size towards the flanks. The species is variable in color ranging from light brown, gray or yellowish, with darker head and tail with incomplete dark bars across the body. Spine-bellied Sea Snakes are widely distributed from northern Australia, New Caledonia, Asia and westwards into the Gulf of Oman and Arabian Gulf (Gardner 2013; Sindaco et al. 2013; Rezaie-Atagholipour et al. 2016). Relatively abundant in the Gulf of Oman, it lives in shallow marine habitats. It feeds on a variety of fish species, amphipods and cuttlefish (de Silva et al. 2011a, b; Rezaie-Atagholipour 2012). Reproductive females measure 53–91 cm (de Silva et al. 2011a, b) and give birth to four to ten young.

3.2.7 Annulated Sea Snake (Hydrophis cyanocinctus)

A long and slender species, reaching lengths of 1.5 m, with a small elongated head which can be distinguished from the neck. The species is variable in colour, with the dorsal light brown or yellowish, with dark bars across the body that are broader dorsally and fade away as they reach sexual maturity. The young are olive or yellowish in base color, ringed with bold black (Buzás et al. 2018) Widely distributed from Japan, westwards into the Gulf of Oman and Arabian Gulf (Gardner 2013; Sindaco et al. 2013; Carranza et al. 2021). In the Arabian Gulf and Gulf of Oman the species is relatively abundant in shallow marine waters over reefs, seagrass beds or sand. It has been observed both during the day and after dusk. The species feeds mainly on small fishes such as mudskippers and gobies (Rezaie-Atagholipour et al. 2013). Females give birth to 3–16 young.

3.2.8 Beaked Sea Snake (Hydrophis schistosus)

A large and robust species reaching lengths of 1.2 meters with a large, blunt head with the tip of snout beak-shaped (Fig. 19.11). The species are variable in colour, ranging from light grey or bluish, with dark bands across the body that fade away or disappear in sexually mature individuals. It is widely distributed from northern Australia westwards to the Gulf of Oman and Arabian Gulf (Gardner 2013; Sindaco et al. 2013; Carranza et al. 2021). It is more frequently encountered in the Gulf of Oman, but is overall less abundant compared to other species found in the region. Beaked Sea Snakes prefer shallow waters near the shore with sandy or muddy substrate and are observed both during the days and after dusk. In parts of the species range it is also found in mangrove and lagoon habitats. It feeds on a variety of fish species, but prefers gobies. Reproductive females measure 1–1.8 m in length (de Silva et al. 2011a, b) and give birth to 4–18 young.

Fig. 19.11

Beaked Sea Snake, adult, from the Gulf of Mannar, Sri Lanka. Photo: Johannes Els

3.2.9 Viperine Sea Snake (Hydrophis viperinus)

A smaller species that reaches 95 cm length. The species is variable in color, from dark gray or bluish dorsally, with dark rhomboid spots. The flanks and ventral are contrasting a lighter shade of the dorsal coloration; the tail tip is often black. The Viperine Sea Snake is widely distributed from the Malay Archipelago and Southern China westwards into the Gulf of Oman and Arabian Gulf (Anderson 1872; Gardner 2013; Carranza et al. 2021). Within the Arabian Gulf the species is known from a single specimen collected in 1963 near Sir Abu Nu’ayr, by the crew of the HMS Dalrymple (British Royal Navy) around 1963 (Gasperetti 1988). The Viperine Sea Snake is a very rare species in the Gulf of Oman, and is only known from the one specimen in the Arabian Gulf. It preys on small fishes, including gobies. Reproductive females measured 59–77 centimeters in length (de Silva et al. 2011a, b) and give birth to 2–6 young.

4 Ecological Importance of Sea Turtles and Sea Snakes

Evidence from numerous archeological sites in the vicinity of Dibba and Khor Fakkan strongly suggest the occurrence of sea turtle egg shells and the remains of turtle hatchlings dating back to the Iron I era (1200 to 1000 B.C.) (Potts 2001). These findings strongly suggest the historic occurrence of turtle nesting on the eastern coast of the UAE, and allude to their social importance as a source of sustenance for coastal communities (Pilcher et al. 2014). Town elders and community members in Kalba also reported as many as 50 turtles nesting annually on the beach of Khor Kalba in the 1960s. They report that these numbers gradually diminished until they were no longer observed in the 1980s. It is believed that turtles may have been inadvertently driven away by the disturbances of human activities in the area (Hebbelmann et al. 2016).

The decline of sea turtles from their historic abundance has received considerable attention from policy makers, the scientific community and the wider public, both in the UAE and internationally. This issue is often framed in the context of animal wellbeing or conservation status. The decrease in turtle abundance is rarely contextualized with the corresponding losses of ecosystem health and functionality of the world’s most essential marine habitats (Wilson 2010).

Along with dugongs, Green Sea Turtles are the only large herbivores in UAE waters. Through grazing, green sea turtles maintain the functional composition and increase the productivity and nutrient content of seagrass beds (Bjorndal 1980; Thayer et al. 1984). Without grazing, seagrass blades can become overgrown, causing excess shade and stagnation that result in seagrasses being overwhelmed by invertebrates and algae (Zieman et al. 1999; Jackson et al. 2001; Jackson 2001). Green Sea Turtles also graze on algae that grow on hard rock substrates. Similarly, Hawksbills consume sponges that also grow on rocky substrates. In doing so, these turtles create opportunities for other species like corals to proliferate (Meylan 1988; León and Bjorndal 2002). Through their contributions to local fisheries, seagrass beds and coral reefs are significant for the economic stability and food security of arid coastal nations like the UAE (McClenachan et al. 2006).

Beach dunes are nutrient deficient habitats, especially in arid environments like the UAE. Eggshells and unhatched sea turtle eggs from turtle nests provide an important source of nitrogen, phosphorus and potassium that support vegetation growth (Hannan et al. 2007). This, in turn, increases the stability of beach dunes and also provides food for terrestrial grazers (Bouchard and Bjorndal 2000; Hannan et al. 2007). Furthermore, turtle eggs and hatchlings are also an important source of food for predators such as Arabian Red Fox (Vulpes vulpes arabica), ghost crabs and sea birds.

The ecological importance of sea snakes and the niche they occupy within the marine environment is still largely unknown. Apart from being predators who feed on various species of fish, sea snakes are also preyed upon by sharks, teleost fish and birds (Heatwole 1975). Sea snakes are often a host for fouling organisms, and may widen the distribution of these organisms within the marine environment. These may include organisms which are specialized and found only on sea snakes, such as the sea snake barnacle (Platylepas ophiophilus). Some species were reported to host bryozoans, which are not restricted to sea snakes only. Solitary fish species have been observed using sea snakes for possible shelter or protection, a behavior termed ‘endoecism’ (Zann et al. 1975).

5 Knowledge Gaps for Sea Turtles and Sea Snakes

5.1 Sea Turtles

Although great advances have been made in recent years to describe population connectivity and identify habitat use by Green and Hawksbill Sea Turtles, allowing the identification of Important Turtle Areas (ITAs) for conservation, further research is required to identify metapopulation dynamics (dispersal of other life stages such hatchlings and juveniles) along with key demographic parameters (population size, mortality and survival rates) derived from long term monitoring programmes.

Further work is also needed to understand the population status of Loggerhead and Olive Ridley Sea Turtles in the UAE. In order to facilitate adequate assessments of population trends, detailed and systematically collected information on population abundance across turtle nesting sites, females’ reproductive biology (nesting success rate, clutch size, nest’s success) and demographic features (annual clutch frequency, and remigration intervals) is also needed. Finally, better understanding of the extent of impact of identified threats to sea turtles in the UAE (pollution, boat strikes, impact of fishing practices that may result in entanglement and bycatch), and less known threats like the effects by climate change on turtle populations and their habitat remain as a priority for sea turtles in the UAE. Research is also required to determine causes for seasonal sea turtle strandings in the Arabian Gulf.

5.2 Sea Snakes

Due to the lack of information from within UAE waters, five species of sea snakes were categorized by IUCN as Data Deficient on a national level. With overall limited information available among the various species, their population status and causes for decline, if any, are unknown which might hinder conservation management in the future. Research is required to gain an improved understanding of the behavior and ecology of sea snakes in the region. What is known about sea snakes in the region is largely based on the work from Gasperetti (1988) for Arabia, with very few recent studies in UAE waters and those are confined to smaller geographical areas such as Buzás et al. (2018) and Soorae et al. (2006). Research focus to date has mainly been along the mainland coast of the UAE, species diversity around islands are overlooked, especially in the Arabian Gulf. Seasonal strandings of sea snakes and the potential causes for this event in the Arabian Gulf and Gulf of Oman, requires long term monitoring.

6 Threats to Marine Reptiles in the UAE

Sea turtles struggle for survival in the face of a variety of anthropogenic threats. The UAE is a rapidly developing nation with a long maritime history. Consequently, much of the urbanization and industrialization involves transformation of coastal areas through reclamation or other forms of coastal engineering (see Chap. 23), all in direct competition with sea turtle survival. This can take many forms including dredging, landfilling, rock piling or water current disruption, and may result in unintended additional pressures for turtles, including beach erosion, pollution, siltation, thermal stagnation, hypersaline plumes and habitat loss (Al Ameri et al. 2022). In the UAE, coastal development has resulted in the degradation of coral reefs, mangrove forests, seagrass beds, oyster beds, salt marshes and sandy beaches (Burt and Bartholomew 2019). Many of these habitats include areas used by sea turtles to forage and nest.

The development of coastal areas also introduces other threats to sea turtle hatchlings. Light is a crucial orientation stimulus for sea turtle hatchlings navigating from their nest into the sea. The introduction of artificial lighting on or near nesting beaches can attract and disorient sea turtle hatchlings, delaying their route to the water, thereby increasing their exposure to potential terrestrial predators, or causing hatchlings to get lost entirely. Light pollution is considered a significant threat for sea turtle hatchlings in many countries across the northwestern Indian Ocean, including the United Arab Emirates region (Pilcher and Al-Merghani 2000; Hanafy 2012; Ghassemi-Khademi 2014; Al Ameri et al. 2022) (see also Chap. 8).

Industrialization and urbanization of coastal areas also increases marine traffic, escalating the sea turtles’ risk of boat strikes. An investigation of sea turtle strandings from the UAE’s east coast reported boat-related traumas on 10.8% of stranded sea turtles (Yaghmour 2020). On the west coast, 20% of sea turtle strandings in Abu Dhabi had injuries consistent with boat strikes (EAD 2016). Another threat extensively investigated in recent years is marine pollutants, particularly marine debris entanglement and ingestion. Marine debris is defined as any manufactured and/or processed solid waste product that is discarded, lost or abandoned into the marine environment (Coe and Rogers 2012; Galgani et al. 2013).

An investigation of sea turtle strandings from the UAE’s east coast documented marine debris entanglement among 5.9% of stranded sea turtles (Yaghmour 2020). Another examination of stranding from the UAE’s west coast along the Abu Dhabi emirate reports 52% of stranded sea turtles entangled in marine debris (EAD 2016). Large quantities of marine debris were observed in the gastrointestinal tracts of 75.0–85.7% of green sea turtles, 83.3% of Hawksbill Sea Turtles, 57.1% of Loggerhead Sea Turtles and 28.6% of Olive Ridley Sea Turtles from the Gulf of Oman (Yaghmour et al. 2018a, 2021b, 2021a). These results are especially concerning when compared to those from a similar study that reports no marine debris was observed in the gastrointestinal tract of green turtles sampled in Oman between 1977 and 1979 (Ross 1985; Schuyler et al. 2014). The majority of ingested debris items consist of white or transparent, threadlike or sheetlike plastics that are mostly composed of polypropylene and polyethylene (Yaghmour et al. 2022a). The findings of those studies also suggest that most ingested debris items were likely to pass through the gastrointestinal tract suggesting that the main risks caused by marine debris ingestion are sub-lethal harms and not instantaneous death (Campani et al. 2013), although several cases were documented to result with lethal effects through obstruction or puncturing of the gastrointestinal tract. Obstruction was mainly caused by ingestion of plastic sheets such as plastic bags or plastic wrapping (Yaghmour et al. 2018a, 2021b, 2021a). Green Sea Turtles, particularly younger individuals, were at greatest risk of this threat as they ingest the greatest quantities of marine debris and also have the longest and narrowest gastrointestinal tracts. Puncturing of the gastrointestinal tract was mainly due to the ingestion of sharp metallic fishing gear such as fishing hooks and rusty fragments of traditional baited basket fishing traps known locally as ‘gargoors’ (Yaghmour et al. 2018b).

Gargoors are dome-shaped basket traps with a funnel-like entrance and a sturdy circular supporting base (Weizhong et al. 2012; Al-Abdulrazzak and Pauly 2013). Traditionally, gargoors were made by weaving fronds from date palms (Phoenix dactylifera), whereas now they are made from galvanized steel (Grandcourt et al. 2008). The circumstances that lead sea turtles to consume metallic gargoor fragments are not entirely clear. It has been observed that the surface of lost and discarded gargoors are often colonized by epibiotic growth including algae, barnacles, molluscs and bryozoa. It is, therefore, believed that sea turtles may attempt to feed on this growth, and in doing so inadvertently consume gargoor fragments that become increasingly brittle through decay and rust (Yaghmour et al. 2018b). Furthermore, decayed gargoors, particularly those with dislodged funnel entrances, were observed to trap and drown sea turtles that happen to wander into them (Yaghmour et al. 2018b; Yaghmour 2020).

With the exception of the Gulf War spill of 1991, oil pollution has largely been overlooked as a threat to marine fauna in the UAE. However, upon closer examination, recent studies reported severe impacts that oil spills have on marine reptiles in the UAE. In one study, 71% of examined Green Sea Turtles contained harmful, petrogenically sourced Polycyclic Aromatic Hydrocarbons (PAHs) in their tissues (Yaghmour et al. 2020). That same study also reports alarming levels of harmful and illegal Organo-Chlorine Pesticides (OCPs), including DDTs, in 25% of examined Green Sea Turtles. Another study from the same area found that marine turtle strandings and mortalities sharply increase in frequency during periods that follow oil spills (Yaghmour 2019b). Finally, one study examined strandings related to an oil spill that took place in November 2021 along the East coast of Sharjah, on the beaches of Kalba (Yaghmour et al. 2022b). During that study, 39 sea snakes of four species (Yellow-bellied Sea Snake, Arabian Gulf Sea Snake, Yellow Sea Snake, Ornate Reef Sea Snake) were investigated. Most (84.6%) of these sea snakes had oil covering most (75–100%) of their bodies. Nearly all (91.4%) sea snakes also had oil covering their eyes and snouts. Furthermore, 25.8% were observed with oil in their mouth, 41.4% had oil residue in their esophagus and over a third (34.5%) had oil inside their stomachs. Overall, the study suggests that the viscosity and stickiness of this oil slick was the main cause of sea snake mortalities. Apart from oil spills sea snakes are also negatively impacted by marine debris and unintentional fishing activities. While the potential negative impact on sea snakes due rising oceanic water temperatures due to climate change and how they will adapt to these changes is uncertain (Fig. 19.12).

Fig. 19.12

Marine reptile threats: Green Sea Turtle with partially ingested thread-like marine debris in its mouth (a); marine debris items found in the gastrointestinal tract of a Loggerhead (b1) and Green Sea Turtle (b2); Green Sea Turtle trapped and drowned inside a gargoor (c); Arabian Red Fox pup with a Hawksbill Sea Turtle egg in its mouth (d); Arabian Gulf Coral Reef Sea Snake stranding coated with oil (e); bycatch of a dozen Green Sea Turtles during drag-net fishing (Photo credits: John Periera (a), Fadi Yaghmour (b–e) and Paul Rivers (f))

7 Management and Conservation Efforts

7.1 National Policies and Management Actions

In the UAE, several national policies and management actions have been taken to conserve sea turtles. This includes the designation of wetlands, under the Ramsar Convention that includes habitats used by marine turtles. The UAE has also designated two sites in the UAE (Bu Tinah Shoal in Abu Dhabi and Sir Bu Nair Island and Protected Area in Sharjah) as sites of regional importance within the Indian Ocean and South-East Asia (IOSEA) Marine Turtle Memorandum of Understanding. The Ministry of Climate Change and Environment (MOCCAE), in collaboration with local authorities, also developed the UAE’s National Plan of Action for Turtles to guide priority conservation actions. Furthermore, the UAE is a signatory to the Convention of International Trade in Endangered Species in Wild Fauna and Flora (CITES) and the Convention of Biological Biodiversity (CBD) which ban turtle hunting, as well as the importing and exporting of bekko. Furthermore, the UAE is also a signatory to the Convention on the Conservation of Migratory Species of Wild Animals (CMS) which confers protection for migratory species like turtles throughout their range. Finally, several marine protected areas have been established to conserve identified sea turtle feeding and nesting habitats.

7.2 Monitoring Programmes

To assess the status of local turtle populations several monitoring programmes were established at key nesting sites in Sharjah, Dubai and Abu Dhabi over the last decade. Other programmes focused on feeding areas are run in Abu Dhabi, by the Environment Agency of Abu Dhabi (EAD) and recently an in-water conservation programme was established by the Environment and Protected Areas Authority (EPAA) in a newly discovered juvenile green turtle feeding aggregation in Sharjahs’s east coast. Biennial aerial surveys conducted by EAD indicate that green and hawksbill turtle populations have remained stable. Furthermore, monitoring via satellite tracking has supported the assessment of Marine Protected Areas (MPAs) effectiveness for the conservation of sea turtles, indicating a great deal of overlap between them and the identified Important Turtle Areas (ITAs) for green turtles in the Emirate of Abu Dhabi. The overlap is less comprehensive in the Northern Emirates followed by the eastern coast where there is a great urgency for the establishment of MPAs.

Stranding monitoring and research conducted by the EPAA’s Sharjah Strandings Response Program (SSRP), has filled the gaps regarding biodiversity, ecology and threats of marine reptiles, marine mammals and seabirds in the Emirate of Sharjah. Through this, the program aims to support the development of evidence-based conservation action and policy in the region as well as educate the wider public on the importance of conserving species and other emerging issues. Additionally, this program acts as an important tool for the response and rescue of live strandings In Sharjah.

7.3 Rescue and Rehabilitation

Several entities in the UAE provide stranded marine reptiles with medical support and care in order to reintroduce them to the sea. The Dubai Turtle Rehabilitation Project (DTRP) was established in Burj Al Arab Jumeirah in 2004 (Fig. 19.13). The DTRP was the first marine turtle rehabilitation center in the UAE and the wider Arabian region. It is run in collaboration with Dubai’s Wildlife Protection Office, with veterinary support provided by the Dubai Falcon Hospital and post mortem examinations conducted in the Central Veterinary Research Laboratory (CVRL). At the time this chapter was written the DTRP had successfully rehabilitated and released 2050 turtles, 69 of them with satellite tags (Barbara Lang-Lenton, pers. comm.).

Fig. 19.13

Release of rescued and rehabilitated Green, Hawksbill and Olive Ridley Sea Turtle (clockwise order from top left) by the Dubai Turtle Rehabilitation Project (Photos: Michael Rall)

Despite being a center that is mostly focused on terrestrial fauna, the Breeding Centre of Endangered Arabian Wildlife (BCEAW), located in the Sharjah Desert Park, receives and rehabilitates stranded sea snakes collected via the SSRP in Sharjah. The BCEAW is currently the only active center in the UAE where sea snakes are rehabilitated. Another center from the Sharjah Emirate is the Khor Kalba Mangrove Center, located in the Alqurm Wa Lehhaffaiiah Protected Area. The Khor Kalba Mangrove Center includes a turtle rehabilitation pond that receives and rehabilitates turtles rescued via the SSRP. It is the only sea turtle rehabilitation center on the eastern coast of the UAE.

In Abu Dhabi, the Wildlife Rescue Program was established as a collaboration between the Environment Agency of Abu Dhabi (EAD), Abu Dahbi’s environment regulatory authority and the National Aquarium (TNA), the largest aquarium in the Middle East. The Wildlife Rescue Program aims to rescue, rehabilitate and release sea turtles as well as other wildlife of the Abu Dhabi Emirate (Himansu Das, pers. comm.).

Though not open at the time this chapter was written, the Yas SeaWorld Research and Rescue Center (YSWRRC) aims to provide expert care for the local marine wildlife, including both sea turtles and sea snakes, through the development of a strong rescue network and the establishment of cutting-edge rescue and rehabilitation facilities. Though the YSWRRC is established in the Emirate of Abu Dhabi, it has ambitions to support wildlife on a national and regional scale (Elise Marquis, pers. comm.).

7.4 Regulation Gaps

Despite the enormous efforts and progress made in marine reptile conservation in the UAE, there still remain several gaps in the current regulatory framework, particularly for sea snakes. Policy and management actions to conserve sea snakes globally is limited to species with restricted distribution ranges, nationally there are no conservation measures in place for any sea snake species. In fact sea snakes are often not included in conservation management plans. Lack of research interest has also led to lack of sufficient data, which hinders appropriate conservation actions.

8 The Future of Sea Turtles and Sea Snakes in the UAE

In light of our current knowledge, derived from monitoring efforts focusing on both green and hawksbill turtles, marine turtle populations in the country are relatively stable thus we believe that there is merit in having a cautious but optimistic view on the future of sea turtles in the UAE. Nonetheless, the increased exposure of marine turtles to marine debris, as demonstrated by the increase in frequency of marine debris ingestion among green sea turtles from 0% in the late 1970s to 75–87% in the late 2010s and early 2020s is a cause of great concern. However, since the UAE Cabinet’s approval of the formation of the UAE Circular Economy Council in January of 2021 (www.moccae.gov.ae), we have observed a series of bold legislative actions that are gradually phasing out single-use plastics. It remains to be seen if these, and future measures will be enough to turn the rising tide of plastics in the UAE waters. To that end we recommended the continued monitoring of marine debris ingestion by sea turtles.

Despite the threats many of the UAE’s coastal industrial, commercial, and recreational developments impose on turtles, these species have demonstrated a degree of behavioral adaptation and population resilience. The integrity, rigor and integration of the Environmental Impact Assessment process into design conceptualization, construction and operational planning can prove critical in reducing or nullifying future harm. In some scenarios, with careful consideration or impact offset implementation, some developments may be able to enhance the productivity of depleted marine zones to the benefit of adult, juvenile and hatchling turtles.

Furthermore there exists uncertainty about consequences of changes in environmental conditions and sea level in light of climate change that could have an important impact on turtle populations and their habitats. Further research efforts on this topic is desirable to facilitate the integration of climate-change adaptation solutions by monitoring programmes. In addition, we recommend the standardization of data collection across established monitoring programmes to understand trends over time.

When considering the lack of data regarding the current and historic status of sea snakes in the UAE, we can only conclude that the future of sea snakes in UAE waters is ambiguous. We can speculate that the dearth of research and conservation efforts focused on sea snakes may result in sustained and unaddressed anthropogenic threats. For example, oil spills, a frequent issue in UAE waters, were only recently observed to have serious impacts on sea snakes. Unpublished ongoing studies are also demonstrating that these species are exposed to harmful chemical residues such as heavy metals, PAHs and OCPs (Fadi Yaghmour, unpubl. data). It is also not known what impact the degradation of feeding habitats such as coral reefs, has on sea snake populations. However, some solace can be gained when considering that, to our knowledge, the nature of sea snakes does not collide directly with the interests of human development, as do sea turtles with their nesting habits. Furthermore, the resources sea snakes rely on are small fish of little or no commercial value for human consumption or exploitation. Additionally, sea snakes were not directly exploited historically as were sea turtles. We highly recommend the establishment of long-term monitoring programs to gain knowledge on how to best ensure the conservation of sea snakes.

9 Conclusion

Marine reptiles are ectothermic, air-breathing vertebrates found in tropical and subtropical waters, with the exception of one species that thrives in colder Atlantic waters. The waters of the UAE are recognized as important sea turtle habitats (Pilcher et al. 2014). In the UAE Green and Hawksbill Sea Turtles are abundant, Loggerhead and Olive Ridley Sea Turtles are observed occasionally, mostly along the eastern coast, while Leatherback Sea Turtles are rare. Sea snakes are the most diverse group of marine reptiles, which includes ten species occurring in the waters of the Arabian Gulf and the Gulf of Oman. Despite declining population levels globally, Green and Hawksbill Sea Turtle populations are considered stable within UAE waters and conservation management actions encouraged to continue. However, the population status of other sea turtle species along with all sea snakes remain understudied and ambiguous. Several challenges and threats face marine reptiles including habitat destruction through coastal development, marine pollution, bycatch and climate change.

10 Recommended Reading

For additional information on the conservation of marine turtles see Al Ameri et al. (2022), Pilcher et al. (2014). Detailed information for marine turtle species read Pilcher (2000). For additional information on marine turtle threats see Yaghmour et al. (2018a, b, 2019b, 2020c, 2021b). For additional details on sea snake biodiversity see Buzás et al. (2018).