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Insights Based on Species Composition of Shark Landings in the United Arab Emirates

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Insights Based on Species Composition of Shark Landings in the United Arab Emirates Mar Biodiv DOI 10.1007/s12526-014-0275-7 ORIGINAL PAPER Shark diversity in the Arabian/Persian Gulf higher than previously thought: insights based on species composition of shark landings in the United Arab Emirates Rima W. Jabado & Saif M. Al Ghais & Waleed Hamza & Mahmood S. Shivji & Aaron C. Henderson Received: 30 July 2014 /Revised: 29 August 2014 /Accepted: 23 September 2014 # Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg 2014 Abstract Although fish fauna in the Arabian/Persian Gulf the existence of the grey bamboo shark, Chiloscyllium have been studied for decades, shark diversity has only been griseum; the tawny nurse shark, Nebrius ferrugineus; the silky recently investigated in the region. Here, we present a first shark, Carcharhinus falciformis; and the sandbar shark, comprehensive account of shark diversity from the United Carcharhinus plumbeus, in these waters. This inventory pro- Arab Emirates based on fishery-dependent data collected at vides an urgently needed assessment of current regional di- market and landing sites over a two-year period of field versity patterns that can now be used as a baseline for future sampling. Landings across the country were dominated by investigations evaluating the effect of fisheries on shark pop- carcharhinids, and six species were found to be most abun- ulations. Results emphasize the need for research on life dant, including the spot-tail shark, Carcharhinus sorrah,and history traits of the various species in order to determine their the milk shark, Rhizoprionodon acutus, contributing 31.8 % regional conservation status, but also reveal that a precaution- and 29.9 %, respectively, of the total number of sharks. While ary approach to conservation will be necessary to mitigate observed landings varied among regions and across seasons, anthropogenic impacts. results showed that shark landings were dominated by small- sized species, which may be a reflection of overexploitation. Keywords Shark . Species richness . United Arab Emirates . We are now expanding the existing checklist of shark species Management . Conservation in the Persian Gulf from 27 to 31, having utilized both mor- phological identification and genetic barcoding in validating Introduction Electronic supplementary material The online version of this article (doi:10.1007/s12526-014-0275-7) contains supplementary material, The Arabian/Persian Gulf (hereinafter referred to as the which is available to authorized users. ‘Gulf’) is a highly stressed ecosystem as a result of the R. W. Jabado (*) : S. M. Al Ghais : W. Hamza prevailing environmental conditions as well as the anthropo- Biology Department, College of Science, United Arab Emirates genic activities that have introduced a number of stressors University, P.O. Box 15551, Al Ain, United Arab Emirates threatening its ecological integrity and sustainability (Hamza e-mail: [email protected] and Munawar 2009). With the rapid economic growth that has M. S. Shivji taken place in the eight bordering countries of Iran, Iraq, Save Our Seas Shark Center, Nova Southeastern University Kuwait, Saudi Arabia, Bahrain, Qatar, the United Arab Emir- Oceanographic Center, 8000 North Ocean Drive, Dania Beach, ates (UAE), and Oman, the marine environment is swiftly FL 33004, USA changing. A. C. Henderson Although the overall biodiversity at the species level is still The School for Field Studies, Center for Marine Resource Studies, poorly understood compared to that of the Arabian Sea, the South Caicos, Turks and Caicos Islands Gulf is considered biologically impoverished, in part because of its young age, but primarily due to its environmental Present Address: R. W. Jabado characteristics (Randall 1995; Sheppard et al. 2010). It is Gulf Elasmo Project, P.O. Box 29588, Dubai, United Arab Emirates believed that most organisms living in the Gulf survive at Mar Biodiv the limits of their physiological tolerance and that marine taxa (White and Weigmann 2014), was also described in the Gulf, here are derived from the penetration of Indian Ocean species bringing the total number of species to 27 (White and through the Strait of Hormuz (Price 1993; Beech 2004a). Weigmann 2014). The limited amount of research currently Basson et al. (1977) reported low species richness in these being directed toward shark diversity, distribution, and biology waters, which was confirmed by most later research on ben- gives rise to doubts about the completeness and accuracy of thic groups such as corals and echinoderms (Price and Coles available regional checklists (Jabado et al. 2014). In the UAE, 1992; Sheppard et al. 1992). On the other hand, the Gulf is there is no established list of shark species other than some also recognized as home to at least four species of marine confirmed sightings within the Gulf recorded during a survey turtles, over 10 cetacean species, the second-largest dugong conducted in 2002 by the Environment Agency – Abu Dhabi population in the world, as well as large numbers of endemic (EAD) (Edwin Grandcourt, pers. comm.) and during a 10-day and migratory birds, suggesting that it could be harboring high visit to a landing site in Abu Dhabi by Moore et al. (2012a). This levels of marine biodiversity (Hellyer and Aspinall 2005). general lack of knowledge on the number of shark species, From a fisheries perspective, various research projects have composition and quantities of catches, and the amount of fishing indicated that anywhere from 200 and up to 550 species have efforts directed toward this fishery suggests that shark species been reported in the Gulf, including reef-associated fishes, richness in the region could be higher than previously recorded. sharks, and rays (Krupp et al. 2000; Grandcourt 2012). In com- This is especially true since it has been shown around the world parison to the fish fauna documented in Oman’s Arabian Sea, it is that with increased research and genetic studies, new species are clear that the Gulf is limited in its fish biodiversity, and few being discovered and described at a rapid rate (Naylor et al. species are endemic to these waters (Randall 1995; Carpenter 2012). et al. 1997; Bishop 2003; Beech 2004b). Furthermore, it appears Globally, shark populations are facing increasing pressure, that there are regional variations in species richness throughout and the advancement of conservation measures requires infor- the Gulf, with fewer species identified in western and southern mation on their biodiversity and conservation status areas, while northern and eastern areas, as well as the deeper (Simpfendorfer et al. 2011). In the UAE, fishermen have waters closer to the Strait of Hormuz, are richer in certain species indicated a general decline in shark catches, abundance, and (Price 1993; Beech 2004b). This is believed to be related to size over the last two decades, suggesting that the shark several factors, including bottom topography and sediment type fishery is currently overexploited (Jabado et al. 2014). How- in the Gulf (Beech 2004b). ever, protection of sharks in the Gulf is hampered by limited Fisheries in the region are described as artisanal, multi-gear, available baseline scientific data, along with the challenge of and multi-species (Beech 2004b;Grandcourt2012). Fishermen balancing conservation efforts with the provision of essential operate two types of boats: small fiberglass dories, or ‘tarad’, resources for growing coastal populations. In order to main- and traditional wooden dhows, or ‘lansh’ (Grandcourt 2012; tain the ecological integrity of the Gulf, it is essential to Jabado et al. 2014). The primary fishing gear utilized on these understand and evaluate potential changes in the marine bio- vessels include drift nets, gill nets, handlines, traps, longlines, diversity of this increasingly threatened aquatic ecosystem. and trolls (Jabado et al. 2014). Although sharks are an important Here, we investigate the diversity of shark species captured component of fisheries and fish trade, their diversity in the Gulf in the UAE artisanal fishery. We present the results of fishery- is still poorly understood (Jabado et al. 2014).Basedona dependent market and fish landing site surveys that can aid in literature review and results from market surveys, the most conservation initiatives both in the UAE and in the broader recent account of shark species in this basin confirms the pres- region. Specifically, we (1) examine patterns of species com- ence of 26 species (Moore et al. 2012b). Although these reports position, distribution, and relative abundance across sites; (2) are based on limited observations and do not reflect changes in investigate temporal and spatial variability in landings com- geographic and temporal trends that may be occurring in the position; and (3) validate the field identification of each spe- basin, they do hold relative value, as they remain the only cies through genetic analysis of a representative sample of species records and measures of abundance levels for sharks in individual species using the Cytochrome c oxidase subunit 1 the region. Furthermore, despite the fragmented nature of these gene (COI). We conclude with a discussion of general impli- surveys, the rate of species discovery is relatively high, with cations for the conservation of shark species in the Gulf. recent documentation and confirmation of new shark species, including the slender weasel, Paragaleus randalli (Compagno, Krupp and Carpenter, 1996); sliteye, Loxodon macrorhinus Material and methods (Müller and Henle, 1839); snaggletooth, Hemipristis elongatus (Klunzinger, 1871); graceful, Carcharhinus amblyrhynchoides Study sites (Whitley, 1934); and hardnose, C. macloti (Müller and Henle, 1839) (Compagno et al. 1996; Moore et al. 2010). More recent- The Gulf is an epicontinental semi-enclosed sea lying in a ly, a new species of whaler shark, Carcharhinus humani sp. nov. subtropical zone with hyper-arid climate, stretching 1,000 km Mar Biodiv in length from the Shatt al-Arab waterway to the Strait of then reduced to twice a month in January 2012. After plotting Hormuz, and varying in width from 75 to 350 km (Carpenter the cumulative number of species present at each market visit et al.
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