ABSTRACT1. Manta and devil rays of the subfamily Mobulinae (mobulids) are rarely studied, large, pelagic elasmobranchs, with all eight of well-evaluated species listed on the IUCN Red List as threatened or near threatened.2. Mobulids have life history characteristics (matrotrophic reproduction, extremely low fecundity, and delayed age of first reproduction) that make them exceptionally susceptible to overexploitation.3. Targeted and bycatch mortality from fisheries is a globally important and increasing threat, and targeted fisheries are incentivized by the high value of the global trade in mobulid gill plates.4. Fisheries bycatch of mobulids is substantial in tuna purse seine fisheries. 5. Thirteen fisheries in 12 countries specifically targeting mobulids, and 30 fisheries in 23 countries with mobulid bycatch were identified.6. Aside from a few recently enacted national restrictions on capture, there is no comprehensive monitoring, assessment or control of mobulid fisheries or bycatch. Recent listing through the Convention on the This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.International Trade in Endangered Species (CITES) may benefit mobulids of the genus Manta (manta rays), but none of the mobulids in the genus Mobula (devil rays) are protected. 7. The relative economic costs of catch mitigation are minimal, particularly compared with a broad range of other, more complicated, marine conservation issues.

As manta rays face increased threats from targeted and bycatch fisheries, manta ray watching tourism, if managed properly, may present an attractive economic alternative to consumptive use of these species. Both species in the genus Manta (Manta alfredi and Manta birostris) are classified by the International Union for the Conservation of Nature Red List as species Vulnerable to extinction in the wild, and are considered unsustainable as fisheries resources due to their conservative life history characteristics, which considerably reduce their ability to recover population numbers when depleted. Utilising dive operator surveys, Internet research, and a literature review, this study provides the first global estimate of the direct economic impact of manta ray watching tourism and examines the potential socio-economic benefits of non-consumptive manta ray watching operations relative to consumptive use of manta rays as a fishery resource. In the 23 countries in which manta ray watching operations meeting our criteria were identified, we estimated direct revenue to dive operators from manta ray dives and snorkels at over US$73 million annually and direct economic impact, including associated tourism expenditures, of US$140 million annually. Ten countries account for almost 93% of the global revenue estimate, specifically Japan, Indonesia, the Maldives, Mozambique, Thailand, Australia, Mexico, United States, Federated States of Micronesia and Palau. In many of the areas where directed fisheries for manta rays are known to occur, these activities overlap with manta ray tourism sites or the migratory range of the mantas on which these sites depend, and are likely to be unsustainable and detrimental to manta ray watching tourism.

ABSTRACT1. Dried gill plates from manta and devil rays, some of the world's most biologically vulnerable fishes, have become a valued commodity in Asian dried-seafood and traditional Chinese medicine markets. This trade is a primary driver of fisheries, which have led to declines in many mobulid populations.2. With no reliable trade statistics and scarce data on mobulid fisheries, this study estimates the number and species of mobulids required to supply this trade, and investigates the consumers and suppliers involved and drivers of demand. Following preliminary market research, 525 trader surveys were conducted in Hong Kong, Singapore, Macau, Taiwan, and southern China.3. Guangzhou, China was identified as the centre of the trade accounting for 99% of total estimated market volume of 60.5 tons of dried gill plates in 2011, increasing to 120.5 tons by 2013. The estimated number of mobulids converted from tons of gill plates more than doubled over the period to 130 000, comprising 96% devil rays, Mobula japanica, Mobula thurstoni, and Mobula tarapacana, and 4% Manta spp. By 2015 the Guangzhou market had declined sharply, reportedly due to conservation campaigns and government policies. However Hong Kong's gill plate sales increased dramatically between 2011 and 2015.4. China, Indonesia, Vietnam, Sri Lanka, and India were reported most frequently as gill plate sources. 5. Vendors recommend gill plates (trade name pengyusai) for ailments ranging from acne to cancer and as a general health tonic. While pengyusai is a new addition to traditional Chinese medicine literature and is rarely prescribed by traditional medicine practitioners, it is readily available over the counter and aggressively marketed by vendors.6. Working in concert with consumer demand reduction efforts, increased measures to restrict mobulid fisheries and trade are recommended to prevent further population declines of these highly vulnerable species.

BackgroundInternational trade for luxury products, medicines, and tonics poses a threat to both terrestrial and marine wildlife. The demand for and consumption of gill plates (known as Peng Yu Sai, “Fish Gill of Mobulid Ray”) from devil and manta rays (subfamily Mobulinae, collectively referred to as mobulids) poses a significant threat to these marine fishes because of their extremely low productivity. The demand for these gill plates has driven an international trade supplied by largely unmonitored and unregulated catches from target and incidental fisheries around the world. Scientific research, conservation campaigns, and legal protections for devil rays have lagged behind those for manta rays despite similar threats across all mobulids.MethodsTo investigate the difference in attention given to devil rays and manta rays, we examined trends in the scientific literature and updated species distribution maps for all mobulids. Using available information on target and incidental fisheries, and gathering information on fishing and trade regulations (at international, national, and territorial levels), we examined how threats and protective measures overlap with species distribution. We then used a species conservation planning approach to develop the Global Devil and Manta Ray Conservation Strategy, specifying a vision, goals, objectives, and actions to advance the knowledge and protection of both devil and manta rays.Results and DiscussionOur literature review revealed that there had been nearly 2.5-times more “manta”-titled publications, than “mobula” or “devil ray”-titled publications over the past 4.5 years (January 2012–June 2016). The majority of these recent publications were reports on occurrence of mobulid species. These publications contributed to updated Area of Occupancy and Extent of Occurrence maps which showed expanded distributions for most mobulid species and overlap between the two genera. While several international protections have recently expanded to include all mobulids, there remains a greater number of national, state, and territory-level protections for manta rays compared to devil rays. We hypothesize that there are fewer scientific publications and regulatory protections for devil rays due primarily to perceptions of charisma that favour manta rays. We suggest that the well-established species conservation framework used here offers an objective solution to close this gap. To advance the goals of the conservation strategy we highlight opportunities for parity in protection and suggest solutions to help reduce target and bycatch fisheries.

International concern is growing with regard to the sustainability of manta and devil ray (collectively mobulids) fisheries as demand for mobulid products has increased in international markets over the last decade. While Indonesia has been reported to be one of the worlds’ top three catchers of mobulid rays, detailed information on these fisheries and the status of Indonesian mobulid populations are lacking. Through collection of historical and recent mobuild fisheries data from published and unpublished sources, this study aimed to identify trends in abundance of Indonesian manta and devil rays and explore socio-economic factors and incentives associated with mobulid fisheries. Comparison of catches from 2001-5 to the most recent data from 2013-14 revealed dramatic declines in mobulid landings over the study period of 64% at Cilacap, 75% at Lamakera, and 94% at Tanjung Luar. The largest declines were observed for Manta spp. and the two large devil rays, Mobula tarapacana and Mobula japanica. Anecdotal reports indicated that catches had declined substantially at three additional sites and local extirpations are strongly suspected to have occurred at three locations. A lack of data on the population ecology of Indonesia’s mobulids makes it difficult to determine whether natural fluctuations may be playing a part in the declining catch rates. However, mobulid life history traits, including low reproductive rates and late age of sexual maturation, indicate that fishing pressure is likely the primary driver in these declines. Interviews in Lamakera, a community which depends on income from its targeted mobulid fishery, suggest that programs focused on education, training and infrastructure development to enable shifts to sustainable livelihood alternatives are likely to offer the most successful path to long-term conservation and management of manta and devil rays, while simultaneously yielding economic and social benefits to fishing communities.