Sympathy for the devil: a conservation strategy for devil and manta rays

Abstract

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.

Seasonal aggregation and diel activity by the sicklefin devil ray Mobula tarapacana off a small, equatorial outcrop of the Mid‐Atlantic Ridge

“…Mobulid rays are distributed in tropical and subtropical coastal waters and also in the oceanic realm (Bigelow & Schroeder, 1953;Couturier et al, 2012;Lawson et al, 2017;Notarbartolo-Di-Sciara, 1987). The sicklefin devil ray Mobula tarapacana (Philippi 1892) is primarily found in oceanic waters Notarbartolo-Di-Sciara, 1987; Thorrold et al, 2014), although they have also been recorded sporadically in coastal areas (Gadig & Sampaio, 2002).…”

“…Mobula tarapacana is listed as Vulnerable by the IUCN (Pardo et al, 2016b). There is a general lack of information on the life history of Mobulidae, thus several species are classified under some level of threat (Croll et al, 2015;Dulvy et al, 2014;Lawson et al, 2017;Pardo et al, 2016a). In Brazil, the capture of all mobulid species is prohibited (MPA/MMA, 2013), but they are occasionally caught as bycatch by the Brazilian tuna fishery (Gadig & Sampaio, 2002;Mendonça et al, 2012;Viana et al 2013).…”

Southernmost record of the Giant Manta Ray Mobula birostris (Walbaum, 1792) in the Eastern Pacific

“…Central and southern Peru share the same marine province as Chile, the WTSP-MP, and the same large marine ecosystem, the HC-LME. Yet, M. birostris is commonly allocated in distribution maps that extend its occurrence to southern Peruvian limits Couturier et al, 2012) and northern Chile (Lawson et al, 2017). The sources of these distribution ranges remains unclear as they are not based on official reports.…”

“…Manta rays (referring now to M. birostris and M. alfredi) are pelagic planktivores, the largest batoid fishes in the world and reported to occur circumglobally in tropical and temperate waters (Couturier et al, 2012). M. birostris is considered the more widely distributed member of the genus as it is broadly spread in the Pacific, Atlantic and Indian oceans (Marshall et al, 2009) while M. alfredi is absent from the Eastern Pacific (Couturier et al, 2012;Lawson et al, 2017). Several biological traits (i.e.…”

“…However, M. birostris is commonly allocated in distribution maps that extend its occurrence to southern Peruvian limits (e.g. Lawson et al, 2017). Peruvian waters present two marine provinces (MP) (Spalding et al, 2007; http:// www.marineregions.org/sources.php): 1) the Tropical East Pacific (TEP-MP), characterized by the Equatorial Current; and 2) the Warm Temperate Southeastern Pacific (WTSP-MP), characterized by the Humboldt Current and the associated upwelling of cold nutrient-rich waters.…”