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.

Focusing on the most critical conservation priorities to prevent extinctions risks missing declines of lower priority taxa that may become tomorrow's emergency. Sawfishes (5 species) underwent catastrophic but largely unnoticed global declines in the latter part of the 20th century, and are now the subject of intensive research and conservation efforts. Guitarfishes (at least 55 species) share many characteristics with sawfishes: they are shark-like batoids with an often large body, prefer sedimentary habitats in warm shallow coastal waters exposed to intensive fisheries, and have high value fins and good quality meat. Guitarfishes represent a unique element of evolution and biodiversity and are vital components of complex coastal socio-ecological systems. Existing global IUCN Red List of Threatened Species assessments for nearly 60% of guitarfish species are 10 or more years old, and over 70% of species are either in threatened categories or Data Deficient. Recently described taxa not yet assessed include those likely to be at risk of extinction. Severe declines and localised extinctions have already been reported for guitarfishes. In notable contrast to sawfishes, total extinction of several guitarfish species is plausible given small distributions occurring solely in developing or least developed countries where conservation is highly challenging. Furthermore, species identification of guitarfishes is often problematic and they may lack the appeal often needed to promote conservation. To ensure that they do not follow the same trajectory as sawfishes, there is an urgent need for comprehensive and coordinated action on guitarfishes, which in many cases could integrate with sawfish conservation efforts.

Article impact statement: Environmental DNA provides habitat-characteristic molecular signatures and can be used efficiently to map marine biodiversity at large spatial scales.

This paper presents data from the first major survey of the diversity, biology and fisheries of elasmobranchs in the Persian (Arabian) Gulf. Substantial landings of elasmobranchs, usually as gillnet by-catch, were recorded in Kuwait, Qatar and the Emirate of Abu Dhabi (part of the United Arab Emirates), although larger elasmobranchs from targeted line fisheries were landed in Abu Dhabi. The elasmobranch fauna recorded was distinctive and included species that are undescribed, rare and have a highly restricted known distribution. Numerical abundance was dominated by sharks (c. 80%), of which carcharhinids were by far the most important. The milk shark Rhizoprionodon acutus and whitecheek shark Carcharhinus dussumieri together comprised just under half of all recorded individuals. Around 90% of recorded sharks were small (50-90 cm total length, L(T) ) individuals, most of which were mature individuals of species with a small maximum size (<100 cm L(T) ), although immature individuals of larger species (e.g. Carcharhinus sorrah and other Carcharhinus spp.) were also important. The most frequently recorded batoid taxa were cownose rays Rhinoptera spp., an undescribed whipray, and the granulated guitarfish Rhinobatos granulatus. The first size, sex and maturity data for a wide range of Gulf elasmobranch species are presented (including L(T) at 50% maturity for males of four shark species) and include some notable differences from other locations in the Indo-West Pacific Ocean. A number of concerns regarding the sustainability of the fishery were highlighted by this study, notably that most of the batoid species recorded are classed by the IUCN Red List as vulnerable, endangered, data deficient or not evaluated. Despite their considerable elasmobranch landings, none of the three countries sampled have developed a 'Shark Plan' as encouraged to do so under the FAO International Plan of Action: Sharks. Furthermore, Kuwait and Qatar currently report zero or no elasmobranch landings to the FAO.