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Overfishing is the primary cause of marine defaunation, yet declines in and increasing extinction risks of individual species are difficult to measure, particularly for the largest predators found in the high seas1-3. Here we calculate two well-established indicators to track progress towards Aichi Biodiversity Targets and Sustainable Development Goals4,5: the Living Planet Index (a measure of changes in abundance aggregated from 57 abundance time-series datasets for 18 oceanic shark and ray species) and the Red List Index (a measure of change in extinction risk calculated for all 31 oceanic species of sharks and rays). We find that, since 1970, the global abundance of oceanic sharks and rays has declined by 71% owing to an 18-fold increase in relative fishing pressure. This depletion has increased the global extinction risk to the point at which three-quarters of the species comprising this functionally important assemblage are threatened with extinction. Strict prohibitions and precautionary science-based catch limits are urgently needed to avert population collapse6,7, avoid the disruption of ecological functions and promote species recovery8,9.

The process of understanding the rapid global decline of sawfishes (Pristidae) has revealed great concern for their relatives, the wedgefishes (Rhinidae) and giant guitarfishes (Glaucostegidae), not least because all three families are targeted for their high-value and internationally-traded ‘white’ fins.The objective of this study was to assess the extinction risk of all 10 wedgefishes and 6 giant guitarfishes by applying the International Union for Conservation of Nature (IUCN) Red List Categories and Criteria, and to summarise their biogeography and habitat, life history, exploitation, use and trade, and population status.Wedgefishes and giant guitarfishes have overtaken sawfishes as the most imperilled marine fish families globally, with all but one of the 16 species facing an extremely high risk of extinction due to a combination of traits – limited biological productivity, presence in shallow waters overlapping with some of the most intense and increasing coastal fisheries in the world, and over-exploitation in target and bycatch fisheries driven by the need for animal protein and food security in coastal communities and trade in meat and high-value fins.Two species with very restricted ranges, the Clown Wedgefish (Rhynchobatus cooki) of the Indo-Malay Archipelago and the False Shark Ray (Rhynchorhina mauritaniensis) of Mauritania may be very close to extinction.Only the Eyebrow Wedgefish (Rhynchobatus palpebratus) is not assessed as Critically Endangered, due to it occurring primarily in Australia where fishing pressure is low, and some management measures are in place. Australia represents a ‘lifeboat’ for the three wedgefish and one giant guitarfish species occurring there.To conserve populations and permit recovery, a suite of measures will be required which will need to include species protection, spatial management, bycatch mitigation, and harvest and international trade management, all of which will be dependent on effective enforcement.

Microsatellites are useful in studies of population genetics, sibship, and parentage. Here, we screened for microsatellites from multiple elasmobranch genomic libraries using an enrichment protocol followed by sequencing on an Illumina platform. We concurrently screened five and then nine genomes and describe the number of potential loci from each respective round of sequencing. To validate the efficacy of the protocol, we developed and tested primers for the pelagic thresher shark, Alopias pelagicus. The method described here is a cost-effective protocol to increase the pool of potential useful loci and allows the concurrent screening of multiple libraries.

The southwest Indian Ocean (SWIO) is a hotspot of endemic and evolutionarily distinct sharks and rays. We summarise the extinction risk of the sharks and rays endemic to coastal, shelf, and slope waters of the SWIO and adjacent waters (Namibia to Kenya, including SWIO islands). Thirteen of 70 species (19%) are threatened: one is Critically Endangered, five are Endangered, and seven are Vulnerable. A further seven (10%) are Near Threatened, 33 (47.1%) are Least Concern, and 17 (24.2%) are Data Deficient. While the primary threat is overfishing, there are the first signs that climate change is contributing to elevated extinction risk through habitat reduction and inshore distributional shifts. By backcasting their status, few species were threatened in 1980, but this changed soon after the emergence of targeted shark and ray fisheries. South Africa has the highest national conservation responsibility, followed by Mozambique and Madagascar. Yet, while fisheries management and enforcement have improved in South Africa over recent decades, drastic improvements are urgently needed elsewhere. To avoid extinction and ensure robust populations of the region’s endemic sharks and rays and maintain ecosystem functionality, there is an urgent need for the strict protection of Critically Endangered and Endangered species and sustainable management of Vulnerable, Near Threatened, and Least Concern species, underpinned by species-level data collection and reduction of incidental catch.

The southwest Indian Ocean (SWIO) is a hotspot of endemic and evolutionarily distinct sharks and rays. We summarise the extinction risk of the sharks and rays endemic to coastal, shelf, and slope waters of the SWIO (Namibia to Kenya, including SWIO islands). Thirteen of 70 species (19%) are threatened: one is Critically Endangered, five are Endangered, and seven are Vulnerable. A further seven (10%) are Near Threatened, 33 (47.1%) are Least Concern, and 17 (24.2%) are Data Deficient. While the primary threat is overfishing, there are the first signs that climate change is contributing to elevated extinction risk through habitat reduction and inshore distributional shifts. By backcasting their status, few species were threatened in 1980, but this changed soon after the emergence of targeted shark and ray fisheries. South Africa has the highest national conservation responsibility, followed by Mozambique and Madagascar. Yet, while fisheries management and enforcement have improved in South Africa over recent decades, drastic improvements are urgently needed elsewhere. To avoid extinction and ensure robust populations and future food security, there is an urgent need for the strict protection of Critically Endangered and Endangered species and sustainable management of all species, underpinned by species-level data collection and bycatch reduction.

The longhorned pygmy devil ray Mobula eregoodoo (Cantor, 1849), formerly known as Mobula eregoodootenkee (Bleeker, 1859), is a small mobulid with a disc reaching a maximum width of 1.3 m, widely ranging in tropical and subtropical latitudes across the Indian Ocean, the Indo-Pacific region, and the western Pacific Ocean. A recently emerged opportunity to examine several (n = 47) M. eregoodoo specimens bycaught in bather protection gillnets off New South Wales, Australia, together with new information assembled from other areas of its range, now allows for a redescription of the species, which was incompletely described in the past because of a paucity of specimens. Based on the morphometric, morphological, ecological, and behavioural elements presented here, corroborated by recent genetic investigations, we argue that M. eregoodoo (Cantor, 1849) is a valid species, distinct from shorthorned pygmy devil ray Mobula kuhlii (Muller & Henle, 1841). These findings are contrary to a recent revision of Mobula, where it was assessed as a synonym of M. kuhlii. The accuracy of taxonomic assessments underpins the effectiveness of species conservation, particularly when direct exploitation or bycatch in various fisheries needs to be managed for sustainability. Failing to recognize that two similar-looking species are distinct, such as M. eregoodoo and M. kuhlii, creates uncertainties that could result in mismanagement and underestimating local and global threats of extinction.

This study evaluates local-scale drivers of shark harvests in India, one of the world’s largest shark fishing nations. Focusing on key harbours in the states of Gujarat and Maharashtra, which together contribute 54% of India’s shark harvest, this study uses a semi-structured survey to examine the practices of shark fishers and traders, their knowledge of shark trade and policy, and perceptions of shark declines. Findings indicate that a domestic market for shark meat is presently the main local driver for harvests rather than the global trade in shark fins. Sharks are mostly non-target catch, landed whole, contributing to the protein needs of coastal communities. Consumer demand is the greatest for small-bodied and juvenile sharks. Perceived steep declines in shark numbers and sizes have had economic impacts on fishers and traders. The unregulated domestic market for shark meat is a key challenge requiring nuanced local approaches that diverge from global shark conservation priorities. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13280-019-01203-z) contains supplementary material, which is available to authorized users.

There is scarce information on the current importance of oyster beds as fishing grounds in the United Arab Emirates (UAE). This study aims to understand the socio-economic value of oyster bed fisheries through questionnaire-based surveys with fishers. Of 106 Emirati fishers interviewed, 67 % use oyster beds due to the proximity to shore, better catch quality, and species abundance. Oyster bed fisheries are recreational and commercial, with handline and fish traps the most common used gears. They provide food for local consumption and cash income. All respondents noticed a fish abundance and size decrease throughout the last decade. Fishers suggest establishing marine protected areas and updating fishing regulations to improve fishing stock status. During the Covid-19 pandemic, oyster fisheries increased, highlighting the value of these fishing grounds for food availability. These fisheries support the local economy and heritage, and urgently need management to ensure the protection of these often-overlooked habitats.

Summary The scale and drivers of marine biodiversity loss are being revealed by the International Union for Conservation of Nature (IUCN) Red List assessment process. We present the first global reassessment of 1,199 species in Class Chondrichthyes—sharks, rays, and chimeras. The first global assessment (in 2014) concluded that one-quarter (24%) of species were threatened. Now, 391 (32.6%) species are threatened with extinction. When this percentage of threat is applied to Data Deficient species, more than one-third (37.5%) of chondrichthyans are estimated to be threatened, with much of this change resulting from new information. Three species are Critically Endangered (Possibly Extinct), representing possibly the first global marine fish extinctions due to overfishing. Consequently, the chondrichthyan extinction rate is potentially 25 extinctions per million species years, comparable to that of terrestrial vertebrates. Overfishing is the universal threat affecting all 391 threatened species and is the sole threat for 67.3% of species and interacts with three other threats for the remaining third: loss and degradation of habitat (31.2% of threatened species), climate change (10.2%), and pollution (6.9%). Species are disproportionately threatened in tropical and subtropical coastal waters. Science-based limits on fishing, effective marine protected areas, and approaches that reduce or eliminate fishing mortality are urgently needed to minimize mortality of threatened species and ensure sustainable catch and trade of others. Immediate action is essential to prevent further extinctions and protect the potential for food security and ecosystem functions provided by this iconic lineage of predators.

SummarySharks and rays are possibly the most threatened Class of marine fishes and their declines can be halted if protected areas are optimised to benefit these species. We identify spatial priorities for all 63 endemic sharks and rays in the marine biodiversity hotspot, the Western Indian Ocean (WIO). Collectively, while the WIO nations currently surpass the 10% Aichi ocean protection target, this amounts to a dismal protection of only 1.57% of each species’ distribution range. We show that the entire ranges of all endemics can be achieved by protecting 11% of EEZs of WIO nations, well within reach of the new 30% of oceans by 2030 target. Regional management bodies exist, which if taken advantage of to implement shark and ray management, provide opportunities to implement more efficient management across the region. We recommend key management actions to implement and explicit incentivisation of international cooperation in the post-2020 biodiversity framework.Science for SocietyThe past decade has seen massive growth in the establishment of marine protected areas (MPAs), driven by the Aichi biodiversity target of protecting 10% of all ocean areas. This expansion of MPAs, however, has largely occurred in areas residual to extractive uses, often coinciding with less threatened areas of lower conservation value. This coming decade will see a further push to ensure 30% of the oceans are protected by 2030. It is important to understand how existing and future MPAs should be placed to benefit threatened biodiversity. Currently this is unclear for sharks and rays, comprising a species group that is the most evolutionarily distinct vertebrate radiation in the world and also one of the most threatened. We identify both regional and national conservation priorities for expanding marine protected areas to benefit all 63 endemic sharks and rays occurring in the Western Indian Ocean region. We find that the region has already exceeded the 10% ocean protection target, but this amounts to an average of only 1.57% protection of the distribution ranges of these species. We show that protecting the top 10% priority sites will conserve almost half of the geographic range of each species yet require only 1.16% of the total EEZ – a tiny fraction of the 30% by 2030 target. We also show that regional collaboration among all nations can result in more spatially efficient conservation priorities. We recommend that the post-2020 biodiversity framework needs to explicitly incentivise regional cooperation between nations to efficiently achieve urgent targets and maximise benefits to biodiversity.

We used a novel approach to estimate the spatial contraction of sawfish populations and guide recovery efforts., Extinctions on land are often inferred from sparse sightings over time, but this technique is ill-suited for wide-ranging species. We develop a space-for-time approach to track the spatial contraction and drivers of decline of sawfishes. These iconic and endangered shark-like rays were once found in warm, coastal waters of 90 nations and are now presumed extinct in more than half (n = 46). Using dynamic geography theory, we predict that sawfishes are gone from at least nine additional nations. Overfishing and habitat loss have reduced spatial occupancy, leading to local extinctions in 55 of the 90 nations, which equates to 58.7% of their historical distribution. Retention bans and habitat protections are urgently necessary to secure a future for sawfishes and similar species.

A total of 138 chondrichthyan species—11% of the world’s known species—are currently known to occur in the waters surrounding the Arabian Peninsula, including 68 sharks from 22 families and 41 genera, 68 rays from 14 families and 33 genera, and two chimaeras from one family and one genus. Of these, 29 species are endemic to the region. The chondrichthyan species assemblage in the Arabian Sea and its adjacent waters do not reflect global shark and ray diversity, with some orders (e.g., Carcharhiniformes, Myliobatiformes, and Rhinopristiformes) very well represented, other taxa (e.g., families Squalidae and Rajidae) poorly represented, and Squatiniformes (angel sharks) entirely absent. Almost all chondrichthyan species found in these waters are heavily impacted by artisanal and industrial fisheries as well as coastal development. In fact, a recent regional IUCN Red List of Threatened Species assessment indicated that over half of them were threatened with extinction. These include species listed on the appendices of both the Convention on the International Trade of Endangered Species of Flora and Fauna and the Convention on the Conservation of Migratory Species of Wild Animals. The lack of overall fisheries management or enforcement of existing measures is a major issue and actions need to be immediately taken to ensure the long-term survival of most chondrichthyan species in the Arabian seas.

The scientific literature on the diversity and biological characteristics of sharks and rays from the Andaman and Nicobar Archipelago fishing grounds is scarce and compromised by species misidentifications. We carried out systematic fish landing surveys in South Andamans from January 2017 to May 2018, a comprehensive and cost-effective way to fill this data gap. We sampled 5,742 individuals representing 57 shark and ray species. Of the 36 species of sharks and 21 species of rays landed, six species of sharks - Loxodon macrorhinus, Carcharhinus amblyrhynchos, Sphyrna lewini, Carcharhinus albimarginatus, Carcharhinus brevipinna, and Paragaelus randalli dominated landings and comprised 83.35 % of shark landings, while three species of rays were most abundant – Pateobatis jenkinsii, Himantura leoparda and H. tutul, and comprised 48.82 % of ray landings. We report size extensions for seven shark species as well as three previously unreported ray species, increasing the known diversity for the islands and for India. For sharks, mature individuals of small-bodied species (63.48 % males of total landings of species less than 1.5 m total length) and immature individuals of larger species (84.79 % males of total landings of species larger than 1.5 m total length) were mostly landed; whereas for rays, mature individuals were predominantly landed (80.71 % males of total landings) likely reflecting differences in fishing patterns as well as habitat preferences and life history stages across species. Further, juvenile sharks and gravid females were landed in large quantities which might be unsustainable in the long-term. Landings were female-biased in C. amblyrhynchos, S. lewini and P. jenkinsii, and male-biased in L. macrorhinus and H. leoparda, indicating either spatio-temporal or gear specific sexual segregation in these species. Understanding these nuances - the composition and biology of sharks and rays landed in different fisheries seasonally will inform future conservation and fishery management measures for these species in the Andaman and Nicobar Islands.

The rehabilitation of wildlife can contribute directly to the conservation of threatened species by helping to maintain wild populations. This study focused on determining the post-rehabilitation survival and spatial ecology of sea turtles and on comparing the movements of individuals with flipper amputations (amputees) to non-amputee animals. Our aims were to assess whether rehabilitated sea turtles survive after release, to compare and contrast the movement characteristics of the different species of sea turtles we tracked, and to examine whether amputees and non-amputees within species behaved similarly post-release. Twenty-six rehabilitated sea turtles from four species, including hawksbill Eretmochelys imbricata (n = 12), loggerhead Caretta caretta (n = 11), green Chelonia mydas (n = 2), and olive ridley Lepidochelys olivacea (n = 1) sea turtles from the United Arab Emirates were fitted with satellite tags before release. Rehabilitation times ranged from 89 to 817 days (mean 353 ± 237 days). Post-release movements and survival were monitored for 8 to 387 days (mean 155 ± 95 days) through satellite tracking. Tag data suggested that three tracked sea turtles died within four days of release, one after 27 days, and one after 192 days from what are thought to be anthropogenic factors unrelated to their pre-rehabilitation ailments. We then compared habitat use and movement characteristics among the different sea turtle species. Although half of all turtles crossed one or more international boundaries, dispersal varied among species. Loggerhead turtles had a high dispersal, with 80% crossing an international boundary, while hawksbill turtles displayed higher post-release residency, with 66% remaining within UAE territorial waters. Amputee turtles moved similarly to non-amputee animals of the same species. Loggerhead turtles travelled faster (mean ± sd = 15.3 ± 8 km/day) than hawksbill turtles (9 ± 7 km/day). Both amputee and non-amputee sea turtles within a species moved similarly. Our tracking results highlight that rehabilitated sea turtles, including amputees, can successfully survive in the wild following release for up to our ~one-year monitoring time therefore supporting the suitability for release of sea turtles that have recovered from major injuries such as amputations. However, more broadly, the high mortality from anthropogenic factors in the Arabian Gulf region is clearly a serious issue and conservation challenge.

Biological data including size, sex ratios, male maturity, and length and weight relationships for four commercially important shark species, including the milk shark (Rhizoprionodon acutus Ruppell, 1837), the grey sharpnose shark (Rhizoprionodon oligolinx Springer, 1964), the spadenose shark (Scoliodon laticaudus Muller & Henle, 1838), and the bigeye smoothhound shark (Iago omanensis Norman, 1939), landed in Porbandar, Gujarat, India, are provided. All four species were landed by trawlers and gill-netters across three defined seasons, with seasonal differences. Higher proportions of mature R. acutus and S. laticaudus were observed in the pre-monsoon season, with neonates caught throughout the year, whereas higher proportions of mature R. oligolinx and I. omanensis were recorded during the monsoon season, with neonates caught in post-monsoon and pre-monsoon, respectively, showing important species-level differences. These small-bodied shark species (less than 1 m in total length) showed positive allometry in their length and weight relationships. Unlike the other three species, I. omanensis showed high disparity in total lengths (L-T) between the sexes, with females being larger than males, and with males maturing faster, with the smallest mature male of 33.58 cm L-T. Females outnumbered males except in R. acutus, and pregnant females of all species were recorded at least once. Of the 971 males recorded across species, 55.1% were mature and 44.9% were immature. Results from this study indicate that there is substantial overlap between the distributions of these species and fishing activities, and show that most, if not all, life stages are susceptible to mortality as a result of fishing. This study provides managers with a better understanding of the life-history traits of these commercially important species to support future quantitative population assessments, and provides a baseline of trends in fishing-related mortality.

The first record of the Ganges shark Glyphis gangeticus from anywhere in its range in over a decade is reported from the Arabian Sea. One female specimen was recorded at Sassoon Docks in Mumbai, India in February 2016, measuring 266cm total length. In light of the Critically Endangered status of this species and its rarity, urgent management actions are needed to determine population size and trends in abundance in combination with fisher education and awareness campaigns. (c) 2018 The Fisheries Society of the British Isles

The Arabian Seas Region plays an important role in the global landings and trade of sharks and rays. The United Arab Emirates (UAE) and Yemen, two countries with stark socio-economic differences, serve as major regional trade hubs for shark and ray products and four countries (Oman, Pakistan, UAE and Yemen) supply nearly 11% of dried fin exports to Hong Kong. Yet, little information is available on the characteristics of this trade and the fisheries contributing to it. Here, we review the fisheries characteristics, trade, utilization and distribution chain of sharks and rays in 15 countries of the Arabian Seas Region based on published and grey literature, landing surveys, field observations and interviews with fishermen and traders. Although regional shark fisheries remain mostly artisanal, reported shark and ray landings represent 28% of the regional total fish production, reaching 56,074 mt in 2012 (7.3% of total world catches), with Iran, Oman, Pakistan and Yemen ranking as the primary catchers. Utilization and distribution patterns are complex, vary between landing sites and countries, and remain unmonitored. Based on widespread over-exploitation of most teleost fisheries, current exploitation levels for most sharks and rays are potentially unsustainable. The situation is exacerbated by limited research and political will to support policy development, the incomplete nature of fisheries data, as well as insufficient regulations and enforcement. A better understanding of shark and ray fisheries will be key for regulating trade, promoting conservation and developing management initiatives to secure food security, livelihoods and biodiversity conservation in the region.

The sawfishes (Pristidae) represent one of the most threatened groups of marine fish around the world. Between October 2015 and June 2016, interviews (n = 82) were conducted to assess the occurrence of sawfish in United Arab Emirates waters and gain insight from fishersí traditional ecological knowledge regarding the status, uses, and cultural significance of sawfish. Almost all respondents (95.1%) had previously seen a sawfish, and 92.6% confirmed that their numbers had declined in the last 20 yr. Most respondents reported encounters in the last 5 to 10 yr, with 18.3% (n = 15) having seen a sawfish in the last 2 yr. Sawfish were not perceived as a culturally significant resource (76.8%) and when caught were primarily used as food, their high-value fins sold to traders, and rostra retained as decorations. The consensus was that while sawfish were previously targeted, they are now caught primarily as bycatch in gill nets. Based on pictures and rostra encountered (n = 19), it appears that the green sawfish Pristis zijsron is more common in United Arab Emirates waters than the narrow sawfish Anoxypristis cuspidata, which is likely to be present off the Ras Al Khaimah coast. While the results of this study provide evidence of a large decline in sawfish, they hint at the possible importance of Abu Dhabi waters as a region where sawfish are still encountered and where research and monitoring, as well as conservation and recovery efforts, should be focused to avoid local extinction and recover their populations.

Overfishing is the primary cause of marine defaunation, yet declines in and increasing extinction risks of individual species are difficult to measure, particularly for the largest predators found in the high seas

Devil rays (genus Mobula) are pelagic elasmobranchs widely distributed throughout tropical, subtropical and warm-temperate waters. Their occurrence and distribution remains poorly documented in the Arabian Seas region. A review is provided of species occurrence in these water bodies along with a synthesis of regional information on their biology and ecology. Based on the available evidence, five Mobula species occur in the region (M. eregoodootenkee, M. japanica, M. kuhlii, M. tarapacana, and M. thurstoni). Of these, three (M. eregoodootenkee, M. tarapacana and M. thurstoni) were found to occur in the Red Sea, and three (M. eregoodootenkee, M. japanica, and M. kuhlii) were found to occur in the Arabian/Persian Gulf. Mobula japanica and M. kuhlii are reported here for the first time in Gulf waters. All five species were found in the Indian Ocean waters between the Gulf of Aden and Pakistan. To address the still uncertain taxonomy of M. kuhlii, a redescription of this species is provided based on a sample of fresh specimen material. Mobula diabolus is a nomen ambiguum, never used to unambiguously designate any newly described species, and its use should be avoided. Considering the life-history traits that make these species particularly vulnerable to fishing pressure, current levels of exploitation in by-catch fisheries are unlikely to be sustainable, despite the fact that the trade in gill plates does not seem to be prevalent in this region. Critical knowledge gaps unfortunately still exist, crippling effective management and conservation actions. Copyright © 2016 John Wiley & Sons, Ltd.

The diversity of sharks occurring off the Andaman and Nicobar Archipelago in India has received increased attention in recent years. Yet, available checklists are out of date, often with inaccurate information and a number of commercially important species have not been documented through research and fish landing surveys. Here we report on shark species examined during fish landing surveys conducted from January 2017 to March 2018. Records of twelve previously unreported species from the archipelago are presented and include the bignose shark (Carcharhinusaltimus), pigeye shark (Carcharhinusamboinensis), bull shark (Carcharhinusleucas), snaggletooth shark (Hemipristiselongata), slender weasel shark (Paragaleusrandalli), Arabian smoothhound shark (Mustelusmosis), Indonesian houndshark (Hemitriakisindroyonoi), sand tiger shark (Carchariastaurus), Indonesian bambooshark (Chiloscylliumhasseltii), tawny nurse shark (Nebriusferrugineus), dwarf gulper shark (Centrophorusatromarginatus), and the Indonesian shortsnout spurdog (Squalushemipinnis). These records increase the reported shark species for the archipelago from 47 to 59 and for India from 114 to 116. Additionally, a size extension in the total length ofC.hasseltiiby 27 cm and ofP.randalliby 8 cm is reported. Owing to the bio-geographical location of these islands, species diversity around the archipelago is unique and appears to overlap with that of southeast Asia. With increasing reports of over-exploitation and the operation of a targeted shark fishery by distant water fleets in these waters, the limited information on shark diversity from this region is of concern. Systematic and long-term monitoring of catches, combined with accurate species identification, is crucial to provide information on management measures.

An 829-bp fragment of the NADH dehydrogenase subunit 2 (NADH2) gene was used to assess the taxonomic status of 1487 elasmobranch specimens, representing 52 putative species. Strong evidence was found for the existence of an undescribed Echinorhinus species and for cryptic speciation within Rhynchobatus djiddensis. The results also provide strong molecular support for the existence of two previously reported, but undescribed, guitarfish species. Potential, but less conclusive, cryptic lineage diversification was also noted in Carcharhinus leucas, Loxodon macrorhinus, Iago omanensis and Gymnura poecilura. A complex situation was found in the genus Himantura, with potentially three distinct lineages evident, one of which is probably an undescribed species, in the H. gerrardi complex. One dasyatid specimen could not be identified, but appears to be closely related to Dasyatis ushiei, while Himantura leoparda and Carcharhinus longimanus are reported from Oman for the first time. The results of the present study also reinforce previously reported geographical divisions within certain putative species, which has important implications for fishery management and conservation. © 2015 The Linnean Society of London

Summary The diets of the milk shark, Rhizoprionodon acutus, and the slit-eye shark, Loxodon macrorhinus, landed from the artisanal fishery in the Arabian Gulf waters of the United Arab Emirates were investigated to determine their dietary preferences. Stomach contents from 57 milk sharks and 53 slit eye sharks were collected from Abu Dhabi (R. acutus, n = 23), Dubai (R. acutus, n = 5; L. macrorhinus, n = 15) and Ras Al Khaimah (R. acutus, n = 29; L. macrorhinus, n = 38) during fishery surveys from January to May 2012. Prey items were identified to the lowest possible taxonomic level, grouped into five categories including ‘teleost fish’, ‘cephalopods’, ‘crustaceans’, ‘invertebrates’, and ‘other’. The diets of both species were described using the numeric, frequency and weight methods, and the index of relative importance (IRI). The majority of stomachs for both species had food, with 66.6% of milk shark stomachs and 90.5% of slit-eye shark stomachs containing prey items, both dominated by small teleosts. Rhizoprionodon acutus fed on a wide variety of teleost species, primarily Engraulidae (anchovies) (28%), Gerreidae (mojarras) (5.6%) and Carangidae (jacks) (1.6%) with occasional crustacean and cephalopod prey (8%). On the other hand, L. macrorhinus seemed to have a preference for one species in terms of teleosts (anchovies) (35.1%) and fed on a wider variety of crustaceans and cephalopods (22.6%). There was little overlap in the diets of these two species, suggesting that they may either be using different habitats or that in these waters, the milk shark is a generalist species while the slit-eye is a specialist feeder.

The extinction risk of sharks, rays and chimaeras is higher than that for most other vertebrates due to low intrinsic population growth rates of many species and the fishing intensity they face. The Arabian Sea and adjacent waters border some of the most important chondrichthyan fishing and trading nations globally, yet there has been no previous attempt to assess the conservation status of species occurring here. Using IUCN Red List of Threatened Species Categories and Criteria and their guidelines for application at the regional level, we present the first assessment of extinction risk for 153 species of sharks, rays and chimaeras. Results indicate that this region, home to 15% of described chondrichthyans including 30 endemic species, has some of the most threatened chondrichthyan populations in the world. Seventy‐eight species (50.9%) were assessed as threatened (Critically Endangered, Endangered or Vulnerable), and 27 species (17.6%) as Near Threatened. Twenty‐nine species (19%) were Data Deficient with insufficient information to assess their status. Chondrichthyan populations have significantly declined due to largely uncontrolled and unregulated fisheries combined with habitat degradation. Further, there is limited political will and national and regional capacities to assess, manage, conserve or rebuild stocks. Outside the few deepsea locations that are lightly exploited, the prognosis for the recovery of most species is poor in the near‐absence of management. Concerted national and regional management measures are urgently needed to ensure extinctions are avoided, the sustainability of more productive species is secured, and to avoid the continued thinning of the regional food security portfolio.

The rapid growth in the demand for shark products, particularly fins, has led to the worldwide overexploitation of many elasmobranch species. Although there are growing concerns about this largely unregulated and unmonitored trade, little information still exists about its dynamics, the species involved and the impact of this pressure on stocks in various regions. Our study provides the first attempt at characterizing the trade in shark products from the United Arab Emirates (UAE), the fourth largest exporter in the world of raw dried shark fins to Hong Kong. A review of trade records and informal interviews with local traders confirmed that the UAE is being used as hub in the broader North Indian Ocean region for the trade in shark products with the Emirati fishery minimally contributing to this trade. Results based on morphological identification of sharks (n = 12,069) and DNA barcoding of tissue samples (n = 655) indicated that the trade was made up of at least 37 species. The most abundant families represented at the Dubai study site were the Sphyrnidae (9.3%), Lamnidae (9%) and Alopiidae (5.9%). While information was mostly limited to shark products originating from the UAE and Oman, results indicated that 45.3% of species traded were considered to be at high risk of global extinction based on the IUCN Red List Global Assessments. Since many of the species found during this survey are likely part of stocks shared with other countries, regional cooperation and management will be crucial to ensure their long term survival. 2014 Elsevier Ltd. All rights reserved.

Hawksbill turtles (Eretmochelys imbricata), which are distributed throughout the world's oceans, have undergone drastic declines across their range, largely due to anthropogenic factors. Assessing sizes, genetic variability and structure of their populations at global and regional levels is critical to the development of conservation management strategies. Here, nuclear and mitochondrial markers were used to analyse patterns of parentage and population structure in hawksbill turtles in United Arab Emirates (UAE) waters, utilizing samples from two life stages (hatchlings and juveniles), and to compare the UAE population with neighboring populations. Weak genetic differentiation was detected between juveniles and hatchlings and between the nesting sites of Dubai and Sir Bu Nair. Parentage analysis suggested that only 53 females and 74–80 males contributed to the hatchlings from 67 nests across three nesting sites in UAE (Dubai, Sir Bu Nair, Abu Dhabi). No females were identified as nesting in more than one location. In Dubai and Abu Dhabi, single paternity was the norm (75%), whereas on Sir Bu Nair, multiple paternity was detected in the majority of nests (67%). Polygyny was also frequently detected on Sir Bu Nair (15% of the overall number of males), but not in the other nesting sites. Comparison of the UAE population with published data from other populations suggests that population structure exists both within the Gulf and between the Gulf and Indian Ocean populations, and that the UAE population has lower genetic variability than the Seychelles population. Finally, the data suggest that the UAE population, and the Gulf population overall, experienced a bottleneck/founder event. The observed overall low genetic variability, evidence of population structure in the Gulf, and strong differentiation between the Gulf and the Indian Ocean populations, raises concerns about the sustainability of this species in this near-enclosed basin. These results highlight the need for regional collaboration in the development of management measures for the long-term conservation of this Critically Endangered species.

We collected movement data for eight rehabilitated and satellite-tagged green sea turtles Chelonia mydas released off the United Arab Emirates between 2005 and 2013. Rehabilitation periods ranged from 96 to 1353 days (mean = 437 ± 399 days). Seven of the eight tagged turtles survived after release; one turtle was killed by what is thought to be a post-release spear gun wound. The majority of turtles (63%) used shallow-water core habitats and established home ranges between Dubai and Abu Dhabi, the same area in which they had originally washed ashore prior to rescue. Four turtles made movements across international boundaries, highlighting that regional cooperation is necessary for the management of the species. One turtle swam from Fujairah to the Andaman Sea, a total distance of 8283 km, which is the longest published track of a green turtle. This study demonstrates that sea turtles can be successfully reintroduced into the wild after sustaining serious injury and undergoing prolonged periods of intense rehabilitation.