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Observations of rays and guitarfish (Batoidea) in shallow waters around Siniya Island, Umm al-Qaiwain, United Arab Emirates

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Nearshore, shallow water habitats are believed to be highly important for various species of threatened sharks and rays (batoids) around the world. Yet, there is limited information on which batoid species use them. During eldwork on Siniya Island in the Emirate of Umm al-Qaiwain, United Arab Emirates (UAE), rays and guitar sh were observed on twelve occasions in shallow waters or found stranded along the shoreline. At least three species were identi ed from at least 20 individuals (adults and juveniles) consisting of the Arabian banded whipray, Maculabatis randalli, the Halavi guitar sh, Glaucostegus halavi, and cowtail rays, Pastinachus sp. Our observations highlight the importance of shallow water habitats for at least these batoids. Many coastal habitats in the UAE and broader region are currently threatened by development projects and other anthropogenic activities, highlighting the urgent need to better understand their role in maintaining shallow subtidal biodiversity.
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76 Tribulus Vol. 25 - 2017
Observations of rays and guitarsh (Batoidea) in shallow waters around
Siniya Island, Umm al-Qaiwain, United Arab Emirates
by Roxanne Whelan, Rima W. Jabado, Chris Clarke & Sabir Bin Muzaffar
Nearshore, shallow waters are highly productive
habitats supporting a rich diversity of species and are
considered extremely valuable ecosystems providing
high quality goods and services to the environment and
economy (Knip et al. 2010; Davy et al. 2015). Many
species of sharks and rays use shallow habitats and their
presence is a crucial component in shaping ecosystem
dynamics (Frisk 2010; Knip et al. 2010).
Globally, sharks and rays face a variety of threats from
shing, habitat degradation, climate change and pollution
(Simpfendorfer et al. 2011) with reports suggesting
that rays, guitarshes, and sawshes have the highest
number of species considered threatened with extinction
on the IUCN Red List of Threatened Species (Dulvy et
al. 2014). With K-selected life histories - long-lived, slow
growing and producing few offspring, batoids are highly
vulnerable to over-exploitation (Frisk 2010; Stevens et
al. 2000). According to Dulvy et al. (2014), of the 539
species of skates and rays assessed by the IUCN, 3%
are considered Endangered, 6% Vulnerable and Near
Threatened respectively, and 25% are Data Decient. The
combined effect of shing, habitat loss and degradation
exposes many of these coastal species to decline (Dulvy
et al. 2014), whilst overshing has ecosystem-wide
consequences (Stevens et al. 2000).
The Arabian Gulf is a unique shallow, semi-enclosed
marine ecosystem, with extreme environmental conditions
and extensive shallow areas of less than 20m (Sheppard
et al. 1992; Naser 2014). This basin is surrounded by one
of the most anthropogenically impacted regions in the
world with continuous pressure due to oil exploitation,
desalination plants, and rapid, large-scale coastal
development as well as concomitant loss of important
marine habitats (e.g. mangroves) (Halpern et al. 2008; Van
Lavieren et al. 2011; Naser 2014). Population growth and
urbanisation in close proximity to the coast compounded by
limited environmental policies or management action have
increased these threats to the marine environment (Van
Abstract
Nearshore, shallow water habitats are believed to be highly important for various species of threatened sharks and
rays (batoids) around the world. Yet, there is limited information on which batoid species use them. During eldwork
on Siniya Island in the Emirate of Umm al-Qaiwain, United Arab Emirates (UAE), rays and guitarsh were observed on
twelve occasions in shallow waters or found stranded along the shoreline. At least three species were identied from
at least 20 individuals (adults and juveniles) consisting of the Arabian banded whipray, Maculabatis randalli, the Halavi
guitarsh, Glaucostegus halavi, and cowtail rays, Pastinachus sp. Our observations highlight the importance of shallow
water habitats for at least these batoids. Many coastal habitats in the UAE and broader region are currently threatened
by development projects and other anthropogenic activities, highlighting the urgent need to better understand their role
in maintaining shallow subtidal biodiversity.
Keywords Batoids • Elasmobranch • Littoral zone • Arabian Gulf • Coastal development • Conservation
Introduction
Lavieren et al. 2011). The United Arab Emirates (UAE) has
experienced rapid coastal development, particularly with
mega-projects and multi-use articial islands changing
the marine ecology and exposing biodiversity to unknown
long-term, irreversible consequences (Hamza and
Munawar 2009; Cressey 2011; Van Lavieren et al. 2011).
Fishing activities in the Arabian Gulf are largely artisanal
but batoids are often incidentally caught while targeting other
species and are mostly discarded (Sivasubramaniam and
Ibrahim 1983; Jabado et al. 2014b). While there has been
an increase in elasmobranch studies and observations in
the region and particularly in the Arabian Gulf (Jabado et
al. 2014a, b; Last et al. 2012; Moore and Pierce 2013;
Robinson et al. 2013), there is still limited research on
batoids. In fact, batoids have long been considered the
most taxonomically problematic of all elasmobranch groups
(Last et al. 2016). The limited information that is available
on most species is confounded with misidentications
making any available data of limited use. Last et al.
(2016) provided the rst comprehensive identication
guide to batoids of the world which includes a number of
taxonomic and nomenclatural decisions to remove the
current ambiguity in the existing classications. Specic to
species occurring in the Arabian Gulf and those covered in
this paper, the genus Rhinobatos is no longer considered
monophyletic and two rhinopristiform families were
erected, namely Glaucostegidae and Trygonorrhinidae
(Last et al. 2016). While nomenclatural issues still exist in
the genus Himantura, it has been subdivided into seven
genera, namely Brevitrygon, Fluvitrygon, Fontitrygon,
Maculabatis, Pateobatis, Himantura, and Urogymnus (Last
et al. 2016). Here we report the occurrence of ray species
that are endemic to the Arabian region from around Siniya
Island in order to record our observations and increase our
knowledge of the spatial ecology of these species in the
Arabian Gulf.
77Tribulus Vol. 25 - 2017
Materials and Methods
Study Area
Siniya Island (25°36’20.63”N
55°36’28.85”E) in Umm al-Qaiwain
(UAE) is 13 km long, located 2 km
offshore (Figure 1), and surrounded
by a variety of habitats - very shallow
waters, seagrass beds, mangroves,
and lagoon inlets. Situated in one of
the least developed Emirates, Siniya
has restricted access and remains
one of the last untouched wetland/
mangrove areas in the UAE. It has been
classied by BirdLife International as
an ‘Important Bird Area’ (Hellyer 2016),
with thousands of migrating shorebirds
visiting every year, and the largest
breeding colony of regionally endemic
Socotra cormorants (Phalacrocorax
nigrogularis) in the Arabian Gulf
(Muzaffar et al. 2017). Figure 1 Map indicating location of Siniya Island, United Arab Emirates within the
Arabian Gulf
Observations
Between March 2014 and November 2016, while monitoring the Socotra cormorant breeding colony on Siniya
Island, batoid observations were recorded. Videos or photographs of specimens were taken when possible, and data
including time, depth and approximate size (Disc Width (DW) or Total Length (TL)) were collected. Identication of
specimens was based on Randall and Compagno 1995; Last et al. 2012; Last et al. 2016.
Figure 2 (a) Maculabatis randalli in shallow waters (b) Maculabatis randalli, bite marks on rear of pectoral disc
(circled) (c) Pastinachus sp. (d) A juvenile Glaucostegus halavi in shallow waters (e) Relatively fresh specimen of
Glaucostegus halavi found ashore.
78 Tribulus Vol. 25 - 2017
Results and Discussion
A total of twelve observations were recorded consisting
of at least 20 animals from three species, the Arabian
banded whipray (Maculabatis randalli), the Halavi guitarsh
(Glaucostegus halavi) and at least one species of cowtail
ray (Pastinachus sp.) (Table 1). It is believed that two
species from the genus Pastinachus occur in the Arabian
Gulf, the Feathertail stingray, P. ater, and the Cowtail
stingray, P. sephen (Moore 2012; Henderson et al. 2016;
Last et al. 2016). Until recently, this genus was thought to
consist of a single widespread species but recent research
has indicated that there are several species (Last et al.
2016). Although they have a characteristic ventral skin
fold on the tail with a stinging spine making them easy
to identify, the dishevelled state of the dead specimens
documented in this study did not allow identication to
species level (Figure 2c).
Six live observations were made between 06.30 –
10.00am in shallow waters up to 1m (e.g. Figure 2a) and
included specimens of M. randalli (n=3 encounters) and
G. halavi (n=3 encounters). The remaining six specimens
were found on land and consisted of two fresh G. halavi
near shore, most likely stranded on the sandbar when
the tide receded (Figure 2e), two M. randalli and two
Pastinachus sp. further inland (e.g. Figure 2d). Based on
the sizes of the specimens observed (Table 1) and their
reported size at maturity (Randall and Compagno 1995;
Last et al. 2012; Last et al. 2016), it is likely these animals
were juveniles. These species were not present in other
surveyed localities nearby and it is therefore possible
that this area is used due to its shallow, sheltered nature
behind sandbars (observed at low tide). On one occasion,
an aggregation of up to six M. randalli individuals within a
3x3m area was observed. Behaviour consisting of chasing,
close-following, mounting, and two individuals ‘ventral to
ventral’ was recorded. Bite markings were observed on
the rear margin of the pectoral disc (Figure 2b). Chapman
et al. (2003) documented similar behaviour in the southern
stingray, Dasyatis americana, and suggested they were
characteristic of mating events. While these observations
do not necessarily infer the occurrence of a nursery or
breeding area (Heupel et al. 2007), they warrant further
investigations to determine the importance of the shallow
waters around Siniya Island during the various life stages
of these species.
Despite the relative abundance of these three species
in coastal waters of the UAE, little information is available
on their life histories and ecology. Last et al. (2012) report
that M. randalli is probably endemic to the Arabian Gulf
and, while it is not commercially valuable, it is often a
by-catch in gillnet sheries. Glaucostegus halavi is listed
as Vulnerable on the IUCN Red List and is generally
retained by shermen due to the high value of its ns
(Simpfendorfer et al. 2017). Finally, P. ater and P. sephen
are listed as Least Concern and Near Threatened (Kyne
et al. 2017; Morgan et al. 2016), respectively. Populations
of these species are increasingly threatened in the region
with little information available on their biology and ecology
(Simpfendorfer et al. 2017; Kyne et al. 2017; Morgan et al.
2016). The observations reported here support the need to
address these data gaps and highlight the importance of
understanding the ecology and spatial structure of batoids
in the Arabian Gulf.
The nature of shallow waters offers sheltered
environments for batoids at all life stages, and such waters
Date Species name Numbers Approximate
size (cm) Comments
11.03.2014 Maculabatis randalli 4 ˜60cm DW Alive, adult
31.03.2014 Pastinachus sp. 1 <30cm DW Dead, shrivelled
28.04.2014 Pastinachus sp. 1 <30cm DW Dead, shrivelled
15.09.2015 Maculabatis randalli 2-6 ˜60cm DW Alive, adults
14.12.2015 Maculabatis randalli 1 ˜50cm DW Alive, adult
17.01.2016 Glaucostegus halavi 1 90cm TL Dead, relatively fresh,
adult
12.04.2016 Maculabatis randalli
Glaucostegus halavi
3
1
˜20-30cm DW
˜30cm TL
Alive, juvenile
Alive, juvenile
30.05.2016 Maculabatis randalli 1 <30cm DW Dead, shrivelled, juvenile
25.10.2016 Glaucostegus halavi 1 ˜30cm TL Alive, juvenile
25.10.2016 Glaucostegus halavi 1 ˜30cm TL Dead, relatively fresh,
juvenile
25.10.2016 Maculabatis randalli 1 <50cm DW Dead, shrivelled, juvenile
17.11.2016 Glaucostegus halavi 2-3 <30cm TL Alive, juveniles
Table 1 Records of batoids observed around Siniya Island by date, species, numbers of individuals and
approximate sizes (DW: Disc Width; TL: Total length)
79Tribulus Vol. 25 - 2017
are used for foraging, aggregating, and breeding. Coastal
development and habitat degradation increases risk to
batoids due to their biological traits, high susceptibility
to disturbance and coastal habitat specicity (Knip et al.
2010; Dulvy et al. 2014). Nearshore habitats are identied
as crucial for juveniles and therefore conservation of
these areas may avoid negative ecosystem effects and
help maintain ray populations (Davy et al. 2015). The
decline or loss of batoids is likely to also have direct
and indirect cascading ecological consequences on the
marine ecosystem (Stevens et al. 2000; Simpfendorfer
et al. 2011). It is essential that social, ecological, and
economic research aspects underpin and inform effective
conservation management initiatives (Simpfendorfer et al.
2011). The shallow waters around Siniya Island appear to
be a small but important area for adults and juveniles of
several species. Such areas need to be protected from
development and disturbance to ensure the conservation
of local and regional marine biodiversity.
Batoids are understudied within the Arabian Gulf
region and those observed and recorded here add to our
knowledge of their spatial ecology, and the importance
of shallow waters. Siniya Island appears to provide good
habitat and attracts individuals at all life stages, but mostly
juveniles.
Acknowledgements
Access to Siniya Island was granted and provided by
the Ministry of Climate Change and Environment (Umm al-
Qaiwain Marine Environment Research Centre). Funding
for eldwork on Siniya Island was from the United Arab
Emirates University Programme for Advanced Research
(UPAR) grant (31S166) to one of the authors (SBM).
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Roxanne Whelan
Department of Biology,
United Arab Emirates University
PO Box 15551, Al Ain, United Arab Emirates
Rima W. Jabado
Gulf Elasmo Project
P.O. Box 29588, Dubai, UAE
Chris Clarke
Department of Biology
United Arab Emirates University
PO Box 15551
Al Ain, United Arab Emirates.
Corresponding author:
S.B. Muzaffar, UAE University
Email: s_muzaffar@uaeu.ac.ae
... The island and its surroundings (Khor Al Beida mangroves) host a variety of habitats including shallow waters, mudflats, seagrass beds, and mangroves, along with desert scrub complexes bordering sandy beaches. The shallow subtidal waters around Siniya Island consist of both rocky and sandy substrate with many sponges -ideal foraging grounds for hawksbills, and important habitats for rays and guitarfish (Whelan et al. 2017). It has been classified by BirdLife International as an 'Important Bird Area' with thousands of migrating shorebirds visiting every year, and the largest breeding colony of the regionally endemic Socotra cormorant. ...
... It has been classified by BirdLife International as an 'Important Bird Area' with thousands of migrating shorebirds visiting every year, and the largest breeding colony of the regionally endemic Socotra cormorant. It remains one of the largest untouched and natural wetlands areas left in the UAE (Whelan et al. 2017), now threatened by a largescale development project (https://www.thenational.ae/opinion/ sustainable-development-must-not-endanger-birds-1.221624). ...
... Similar habitat preferences have been documented for G. typus and the Halavi Guitarfish (G. halavi) from nearshore waters in Australia and United Arab Emirates respectively (Whelan et al., 2017;Freeman, 2019;Gaskins et al., 2020;Heithaus, 2012, 2013;White et al., 2014b). The dorsoventrally flattened morphology of giant guitarfishes allows juveniles to enter very shallow waters which are inaccessible to larger marine predators such as Tiger Sharks (Galeocerdo cuvier), providing a refuge from predation that increases survival Heithaus, 2012, 2013). ...
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... Bien que la morphologie des vertèbres de Pristidae ne permet pas de pousser l'identification jusqu'au niveau spécifique, Pristis zijsron est la seule espèce de poisson-scie attestée dans le Golfe persique (Moore 2014). Elle est, par ailleurs, toujours mentionnée comme présente dans la zone de Dalma (Jabado et al. 2017 : fig. 1). ...
Thesis
Cette thèse intègre l'analyse inédite de plus de 80 000 restes provenant des sites néolithiques d'Akab, de Dalma et de Marawah MR11 (Emirats Arabes Unis) – occupés entre la moitié du VIe et la fin du IVe millénaire av. n. è. Les résultats dévoilent des pêcheries déjà investies dans l'exploitation d'une grande variété de milieux marins. Les poissons capturés et consommés par ces pêcheurs incluent de nombreux sargues, pagres (Sparidae), empereurs (Lethrinidae) et petites aiguilles (Belonidae) qui témoignent avant tout de l'exploitation des eaux côtières peu profondes : le long des rivages ainsi que dans les zones d'herbiers et de récif frangeant. À Akab, la pêche dans la lagune et la mangrove est également reflétée par la présence de nombreux poissons‐chats marins (Ariidae) et mulets (Mugilidae) dans l'assemblage. Les techniques impliquées dans ce type de pêche sont peu sélectives et relativement simples : la prospection des petits fonds à l'aide de senne, la pose de filets calés, voire l'utilisation de barrages à poissons. À Dalma, des nasses étaient probablement déjà employées dans les zones de récifs moyennement profondes, pour la capture de mérous en particulier (Serranidae). Les mangroves et les zones de récifs sont des environnements très productifs auprès desquels les pêcheurs pouvaient vraisemblablement se fournir en poissons et en coquillages tout au long de l'année. En l'occurrence, ceux d'Akab connaissaient et exploitaient probablement déjà les grands rassemblements de becs‐de-cane (Lethrinus nebulosus) près de la lagune d'Umm al‐Quwain, au printemps et à l'occasion de leur frai. L'étude du matériel d'Akab et de Dalma révèle toutefois aussi l'existence d'expéditions de pêche en mer ouverte, impliquant l'usage de bateaux. Ces expéditions sont notamment conduites à la recherche des bancs de thonines (Scombridae) voire de carangues (Carangidae). Leur pêche n'impliquait pas seulement l'emploi de lignes munies d'hameçons en nacre mais aussi celui de filets tels que des sennes tournantes. Ces filets ont également permis aux pêcheurs de Dalma de capturer de grands requins et quelques dauphins plus occasionnellement. Bien que la pêche des bancs de pélagiques soit aujourd'hui considérée comme une activité hivernale dans les pêcheries du Golfe persique, l'existence d'un climat plus humide au Néolithique, alors soumis au régime de la mousson de l'Océan Indien, invite à nuancer nos modèles de saisonnalité. Au Néolithique, la pêche était ainsi pratiquée à la fois de manière généraliste et de manière spécialisée en faisant contribuer un large panel de techniques et de savoirs écologiques aux besoins d'une économie de subsistance reposant principalement sur l'exploitation des ressources marines.
... Niebuhr 1775) -Halavi guitarfish Status in Persian Gulf: First record from Persian Gulf by Moore et al. (2012a) as Rhinobatos halavi; subsequently reported by Séret et al. (2016b), Whelan et al. (2017) and Jabado (2018). Distribution: Red Sea, northwestern Indian Ocean: Persian Gulf, Gulf of Oman to Pakistan. ...
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This checklist aims to reviews and summarize the results of the systematic researches on the Persian Gulf ichthyofauna that has been carried out for more than 200 years. Since the work of C. Niebuhr, a Danish biologist in the 18th century, the number of valid species has increased significantly and the systematic status of many of the species has changed, and reorganization and updating of the published information has become essential. Here we take the opportunity to provide a new and updated checklist of fishes of Persian Gulf based on literature and taxon occurrence data obtained from natural history and new fish collections. The total confirmed fish species of Persian Gulf comprise 744 species, 131 families, 445 genera and 27 orders. In the class Chondrichthyes, the most diverse family is Charcharhinidae with 23 species (41.89%), followed by Dasyatidae with 15 species (31.08%). Within the class Actinopterygii, Gobiidae with 65 species (9.70%), Carangidae with 45 species (6.27%), Serranidae with 25 species (3.73%), Apogonidae with 25 species (3.73%), Lutjanidae with 23 species (3.43%) and Blenniidae with 23 species (3.43%) are the most diverse families in the Persian Gulf.
... The Brazilian guitarfish (R. horkelii) is also known to migrate to coastal waters into depths of less than 20 m from November to March to give birth (Lessa and Vooren, 2005). Female G. halavi have been recorded seeking shallow waters to give birth between May and November in the Red Sea (Gohar and Mazhar, 1964) and reported, along with juveniles, from shallow waters of the UAE in the autumn months (Whelan et al., 2017). This presumably seasonal migration to shallow waters makes shark-like batoids particularly vulnerable to inshore fishing activities (i.e., gillnets and trawls) as well as habitat modifications. ...
Article
Shark-like batoids (Rhinopristiformes) represent of some of the most threatened families of sharks and rays. In certain regions, they are a relatively important component of elasmobranch fisheries, commonly taken as by-catch in gillnets and longlines, but also increasingly targeted for their high value fins and meat. This demand, combined with intense fishing pressure, has resulted in global population declines as well as localized extinctions of many rhinopristoids. Yet, information on the life-history, ecology, and conservation status remains scarce for most species. From 2010-2012, data was opportunistically collected from thirteen rhinopristoid species, including four endemic to the Arabian Sea and adjacent waters, landed from fisheries in the United Arab Emirates or transported from Oman. Four taxa dominated and comprised 92% of total shark-like batoid landings by number, namely Rhynchobatus spp., the Halavi guitarfish (Glaucostegus halavi), bowmouth guitarfish (Rhina ancylostoma), and Bengal guitarfish (Rhinobatos annandalei). Details of the biological characteristics, including size composition and sex ratios, are presented for each species. While there remain identification challenges related to some unresolved taxonomic issues, with several likely undescribed species occurring in the region, the first regional checklist of rhinopristoids is provided. Evidence of significant declines in landings combined with increasing fishing effort over a short time period raises concern about the status and long-term persistence of many species. Increased research to understand the biology, ecology, diversity, and resilience to harvest by fisheries is critical to the effective management of these species and an urgent precautionary approach to their conservation is warranted.
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Data on the diversity and relative abundance of elasmobranchs (sharks and rays) in the Arabian Gulf have been limited to fishery-dependent monitoring of landing sites. Understanding the diversity and abundance of sharks and rays is, however, crucial to inform policy and management plans. Baited Remote Underwater Video Surveys (BRUVS) were conducted in 2015–2016 across the United Arab Emirates Arabian Gulf waters encompassing a range of depths and habitat types. Data from 278 BRUVS (757 hours soak time) were analysed to gather information on diversity, relative abundance, species distribution, and habitat associations. Surveys recorded 213 individuals from 20 species of sharks and rays at 129 stations. The frequency of occurrence of species usually discarded by fishers such as the Arabian carpetshark (Chiloscyllium arabicum) and stingrays (Himantura spp.) was high, accounting for 60.5% of observed elasmobranchs. Despite the large survey area covered and extensive sampling effort, the relative abundance of sharks and rays was low at 0.28 elasmobranchs per hour, 0.13 sharks per hour, and 0.15 rays per hour. This CPUE was reduced to one of lowest recorded abundance on BRUVS from around the world when removing the two discarded species from the analysis (0.11 elasmobranchs per hour). These results likely reflect the intense fishing pressure and habitat loss contributing to population declines of many elasmobranchs in the Arabian Gulf. Findings provide a baseline for future work and can support the design of conservation strategies for sharks and rays in the UAE.
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An 829-bp fragment of the NADH dehydrogenase subunit 2 (NADH2) gene was used to assess the taxonomic statusof 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.
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Although fish fauna in the Arabian/Persian Gulf have been studied for decades, shark diversity has only been recently investigated in the region. Here, we present a first comprehensive account of shark diversity from the United Arab Emirates based on fishery-dependent data collected at market and landing sites over a two-year period of field sampling. Landings across the country were dominated by carcharhinids, and six species were found to be most abundant, including the spot-tail shark, Carcharhinus sorrah, and the milk shark, Rhizoprionodon acutus, contributing 31.8 % and 29.9 %, respectively, of the total number of sharks. While observed landings varied among regions and across seasons, results showed that shark landings were dominated by small-sized species, which may be a reflection of overexploitation. We are now expanding the existing checklist of shark species in the Persian Gulf from 27 to 31, having utilized both morphological identification and genetic barcoding in validating the existence of the grey bamboo shark, Chiloscyllium griseum; the tawny nurse shark, Nebrius ferrugineus; the silky shark, Carcharhinus falciformis; and the sandbar shark, Carcharhinus plumbeus, in these waters. This inventory provides an urgently needed assessment of current regional diversity patterns that can now be used as a baseline for future investigations evaluating the effect of fisheries on shark populations. Results emphasize the need for research on life history traits of the various species in order to determine their regional conservation status, but also reveal that a precautionary approach to conservation will be necessary to mitigate anthropogenic impacts.
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The Arabian Gulf (also known as Persian Gulf and ROPME Sea) represents an extremely important economic, political and strategic aquatic resource. Although the Gulf region is known world wide for its oil-gas deposits and production, very little is known about its ecosystem health, food web dynamics, fisheries, biodiversity and sustainability. The present study reviews and highlights the major anthropogenic stressors which threaten the marine and coastal ecosystems of the Gulf. The Arabian Gulf environment lacks the holistic, ecosystem-based research and monitoring that have been conducted in other marine ecosystems. There is a need for multi-disciplinary, multi-trophic and multi-agency international investigations including the application of emerging technology. Such an integrated strategy is urgently needed to save the rapidly changing marine ecosystems from the impact of rapid and vigorous coastal development across the entire Gulf region. The necessity of developing and implementing ecosystem health agreements between the various riparian countries is emphasized for expeditious protection, conservation and management of this precious but threatened natural heritage.
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Understanding the extent of movements and space use of animals is necessary to identify vital habitats and better conserve and manage vulnerable species. We used acoustic telemetry to examine movement patterns and habitat use of juvenile mangrove whiprays (Himantura granulata) in an intertidal bay at Orpheus Island, Australia. Thirteen juveniles were acoustically monitored between March and December 2012, and in July 2012, four active tracks were completed. The majority of the acoustically monitored rays remained within the intertidal bay for the entire monitoring period. Tidal changes caused rays to move from the inner-bay mangrove (high tide) habitat to coral reef in the outer bay (low tide). Actively tracked rays moved in a directed way during running tides, remaining in shallow water. During periods of high and low tide, when rays refuged in mangrove or reef habitats, movement was limited and sinuosity was high. In mangrove areas, rays were most commonly observed refuging under or close to mangrove roots, and rarely in open sand areas. Refuging behaviour in mangrove and reef habitats suggested that predation risk may be the predominant factor influencing the movement of small rays. The continuous use of intertidal habitats demonstrates their importance to Himantura granulata.
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Anecdotal evidence suggests that sharks are being targeted in the United Arab Emirates artisanal fishery. However, little information is available on this fishery and baseline information is essential for understanding its impact on shark populations in the Arabian/Persian Gulf, and for managing sharks in this region.The aim of this study was to investigate the artisanal shark fishery and gain an insight into the social, motivational and economic drivers behind it. Fishery characteristics were examined and the effect of fishing on local shark stocks assessed by interviewing Emirati fishermen across the country (n = 126).Sharks were found to be increasingly targeted owing to their high value in the global fin trade industry. The majority of fishermen (80%) confirmed that changes in species composition, abundance and sizes of sharks have been continuing for more than two decades, mainly because of overfishing, raising concerns about the sustainability of this fishery.Results suggest that sharks are likely to be overexploited and that management measures will need to take into account the precautionary principle. There is an urgent need to formulate long-term and effective conservation and management plans to prevent further declines in a number of species.Additional efforts should be directed to quantify the ecological implications of the observed changes and determine if these are aggravated by the life-history traits of the fished species. Such implications should be considered when assessing the sustainability of local fisheries.The data gathered can now serve as a reference to managers, fisheries scientists and other stakeholders to prioritize future research as well as lay foundations for the development and implementation of national management plans for the protection and conservation of sharks. Copyright © 2014 John Wiley & Sons, Ltd.
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The first detailed elasmobranch fisheries data for the Kingdom of Bahrain are presented, based on surveys of fish markets in April 2012. At least 25 species were recorded, including undescribed taxa. The milk shark Rhizoprionodon acutus was the most frequently recorded species; together with the Arabian smoothhound Mustelus mosis and banded eagle ray Aetomylaeus nichofii, these species comprised 53% of individual abundance. Sharks were almost entirely small individuals <1 m total length (TL). Males of small shark species were largely mature, whereas nearly all individuals of larger sharks were immature. For several elasmobranch species, landings were significantly biased towards males, which were largely mature. The species assemblage showed some notable differences in composition to that of adjacent Qatar, sampled at the same time of year, highlighting the importance of local data collection.
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Records are presented of several species of batoid fish from the north-western Indian Ocean that are poorly known, of taxonomic interest, or of conservation concern. For the Persian (Arabian) Gulf, the first records of Rhinobatos halavi, Himantura fai, and the first substantiated record of a devil ray (Mobulidae), provisionally identified as Mobula cf. eregoodootenkee, are presented. Literature on mobulids in the Persian Gulf area is briefly reviewed, and a historic record of Manta birostris extends the known range of this species to the Arabian Sea off Pakistan. New records of Himantura granulata from the Gulf of Aden and the Gulf of Aqaba are the first for the continental coast of the western Indian Ocean. The existence of a distinctive Rhynchobatus guitarfish from the Arabian Sea requiring taxonomic clarification is reported.