Mobulid rays, including the Sicklefin Devil Ray, are both targeted and caught incidentally in industrial and artisanal fisheries (Couturier et al. 2012, Croll et al. 2016). These rays are captured in a wide range of gear types, including harpoons, drift nets, purse seine nets, gillnets, traps, trawls, and longlines. Their coastal and offshore distribution, and tendency to aggregate, makes mobulid rays susceptible to incidental catch in purse seine fisheries and longline fisheries, and susceptible to targeted capture in artisanal fisheries and incidental entanglement (Croll et al. 2016, Duffy and Griffiths 2017). However, there are an increasing number of studies that indicate that gillnet fisheries are responsible for a significantly higher proportion of mobulid interactions (>99%) compared to purse seine fisheries (Martin 2020, Bucair et al. 2024, Rojas-Perea et al. 2025). Incidental catch in these fisheries is believed to be an important source of mortality (Martin 2020). Like many mobulid rays, the Sicklefin Devil Ray is easy to target because of its large size, slow swimming speed, tendency to aggregate or predictably use specific habitats, and its general lack of human avoidance (Couturier et al. 2012).
Mobulid rays are caught in at least 85 countries worldwide, with at least 87% of catches originating from fisheries operating small vessels (or ‘small-scale’ fisheries) (B. Laglbauer unpubl. data 2025). When comparing estimates of annual catch/landings, Indonesia, India, Sri Lanka, Myanmar, and Peru are the major mobulid fisheries globally, each catching >10,000 mobulids per year (Fernando and Stewart 2021, Rojas-Perea et al. 2025, T. Ko Gyi pers. comm. 20/03/2025 2025, B. Laglbauer unpubl. data 2025). At least 31 countries catch the Sicklefin Devil Ray, but when considering flag states, >45 countries capture these species. Comparing estimates of annual mobulid catch, Sri Lanka and Indonesia emerge as the leading fisheries for the Sicklefin Devil Ray globally, followed by India, the Philippines, Pakistan, Bangladesh, and large-scale fisheries off West and Central Africa, and the Eastern Tropical Pacific (Couturier et al. 2012, Ward-Paige et al. 2013, Croll et al. 2016, Moazzam 2018, Rambahiniarison et al. 2018, Lezama-Ochoa et al. 2019, Haque et al. 2021, Clavareau et al. 2020, Fernando and Stewart 2021, M. Chopra pers. comm. 18/02/2025, B. Laglbauer unpubl. data 2025). In some directed artisanal fisheries, hundreds of Sicklefin Devil Ray have been observed or estimated to be landed each year, while estimated incidental catch (mostly in drift gillnets) has reached >10,000 individuals landed each year in Indonesia and Sri Lanka (Alava et al. 2002, Dewar 2002, White et al. 2006b, Fernando and Stevens 2011, Lewis et al. 2015, Acebes and Tull 2016, Fernando and Stewart 2021, B. Laglbauer unpubl. data 2025). While many artisanal fisheries have grown into trade fisheries, some still target these rays mainly for food and local products (White et al. 2006b, Fernando and Stevens 2011, Palacios et al. 2025). Prices per kilogram vary widely across countries catching mobulid rays, including those known to land the Sicklefin Devil Ray. Mobulids are typically retained because of (1) their relatively high value (due to demand for meat and/or gills), or (2) the relatively large volume of animals (for use as a cheap protein source, or as bait and fish feed) (Palacios et al. 2025). Even when discarded alive, for example from tuna purse seine fisheries, they are often injured and have high post-release mortality (Tremblay-Boyer and Brouwer 2016, Francis and Jones 2017, Stewart et al. 2024). However, under optimal handling conditions, survival rates can be as high 74.2–95.3% in purse seine fisheries (Stewart et al. 2024).
Even after listing on Appendix I and II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS), Appendix II of the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES), non-retention measures at four tuna-Regional Fisheries Management Organizations, and increasing national fishing bans, most fisheries interacting with these species remain open and active. Robust, quantitative assessments are challenging because multiple mobulid species are caught and landed simultaneously, and species identification continues to be a source of error in this group (Croll et al. 2016).
Global landings of mobulid species, including the Sicklefin Devil Ray, increased steadily between 1990–2015 due in large part to the rise in demand for gill plates (O’Malley et al. 2017). Many former fisheries incidentally capturing these species expanded into directed commercial export fisheries (Dewar 2002, White et al. 2006b, Fernando and Stevens 2011, Heinrichs et al. 2011, Acebes and Tull 2016). Between 2000–2016, combined total landings of ‘Manta, devil rays nei’ ('nei' refers to 'not elsewhere included'), ‘Mantas, devil rays, etc. nei’, and ‘Giant manta’ increased from 931 tonnes to 8,083 tonnes (FAO FishStat Capture Production database 2025). These landings then declined by 87% to 2023 (1,028 t) despite an increase in the number of countries reporting from 2016 onwards. While this equates to an average of 2,423 t per annum (2000–2023), reported landings are likely to represent only a fraction of total fishing-related mortality (e.g., Ward-Paige et al. 2013). Only 12 countries reported catches to the FAO (Colombia, Ecuador, Indonesia, Kenya, Liberia, Mauritania, Mexico, Pakistan, Peru, Puerto Rico, and Sri Lanka), with reporting periods ranging from one (Puerto Rico, Kenya, Colombia) to 19 years (Indonesia). Compared with recent estimates of global mobulid catch per year (~264,000 individuals), this represents less than 1% of catches reported to the FAO (B. Laglbauer unpubl. data 2025).
Mobulid rays are also taken as incidental catch in pelagic gillnet and longline fisheries in the Indian Ocean targeting swordfish (Coelho et al. 2011), and the tuna purse seine fishery (Lezama-Ochoa et al. 2015), but effort trends for these fisheries are unknown. In India, intensive gillnet fisheries take mobulid species, particularly the larger-bodied species like the Sicklefin Devil Ray, along the western coast (Rajapackiam et al. 2007, Kizhakudan et al. 2015, Nair et al. 2015). In Sri Lanka, it is estimated that the Sicklefin Devil Ray comprises 17% of the total number of devil rays landed, with an estimated median of 4,867 individuals landed annually as of 2019 (Fernando and Stewart 2021). In Tanzania, 19 Sicklefin Devil Rays were recorded in landing surveys in Zanzibar (although mainland was also surveyed) between 2019–2023 with at least half of these individuals reported as incidental catch from gillnet fisheries (Wildlife Conservation Society pers. comm. 30/03/2025).
Data from French purse seiners operating in the western Indian Ocean between 2005 and 2023 (observer coverage varying between 1–12% until 2012 and 14–47% after 2012) indicate that 311 individuals were captured (Sabarros et al. 2024). Sicklefin Devil Ray (n=23) represented 7.4% of catches, noting that 32% of animals were not identified to the species level. This suggests a total estimated catch of up to 38 t per year. All animals were discarded and by 2023, up to 89% of animals were released alive, although post release survivorship has not been assessed (Sabarros et al. 2024).
In the Western and Central Pacific from 2010 to 2015, observed incidental catch of mobulids (excluding Oceanic Manta Ray) in purse seine fisheries was 4,324 individuals, and in longline fisheries was 410 individuals. Some of these were identified as the Sicklefin Devil Ray, although the numbers of individuals reported were low (from 1995 to 2015, 32 in purse seines and 86 in longlines) and the numbers reported as Mobula spp. were much higher, hence many were not identified to species level (Tremblay-Boyer and Brouwer 2016).
Eastern Pacific Ocean (EPO) fisheries data indicate a substantial increase in the incidental catch of mobulid rays. Between 1993–2013, an average of 2,800 individuals were caught per year, with a range of 1,100–6,500 (Croll et al. 2016). Purse seine fisheries in this region capture the greatest volume of mobulid incidental catch when compared to other gears and regions (Mas et al. 2015, Croll et al. 2016, Alfaro-Cordova et al. 2017). Around 4,700 individuals per year were taken in purse seiners in the EPO between 1993 and 2009 (Alfaro-Cordova et al. 2017). Much of the devil ray catch in this area occurred in the Costa Rica Dome region off Central America (Croll et al. 2016). In Peru, mobulid rays account for 28% of total ray catch, with the majority being captured in gillnets (Rojas-Perea et al. 2025). The Inter-American Tropical Tuna Commission purse seine vessels with observers operating during 2015 in the EPO reported 71 t of mobulid landings, and this likely included the Sicklefin Devil Ray (Miller and Klimovich 2017). Mobulid catch by Mexico is especially prominent along the Eastern Pacific coastline, where an estimated ~ 2,459 individuals are caught annually (Laglbauer et al. unpubl. data 2025), although incidental catch has been reported along the Atlantic Ocean coast too (Bizzarro et al. 2009, Cartamil et al. 2011, Gonzalez-Gonzalez et al. 2020; K. Fuentes, pers. comm. 20/11/2024).
An assessment of extinction risk of sharks and rays in Australia indicates that most mobulid rays are not likely to interact with Australian fisheries due to habitat, behaviour, and limited catchability which suggests that there is limited impact from these fisheries on the Spinetail Devil Ray across this range (Kyne et al. 2021).
In the markets of Guangzhou, China, where 99% of mobulid products are routed, mobulid products are sourced from over 20 countries and regions (O’Malley et al. 2017). The source locations for the largest quantities of product are Indonesia, Sri Lanka, India, China, and Viet Nam (O’Malley et al. 2017). Demand for products has driven up the price and traded volume of these products since the 2000s. Between 2011 and 2013, there was an increase from 60 to 120 t of mobulid product moved through shops in Guangzhou (O’Malley et al. 2017). Approximately 13% of the estimated number of devil rays traded annually through the shops in Guangzhou are the Sicklefin Devil Ray, and this species’ gill plates are reported to sell for up to US$359 per kg (O’Malley et al. 2017).
Indirect and sublethal sources of mortality include habitat destruction and degradation, climate change, ocean acidification, oil spills, and other pollution and contaminants (e.g., heavy metals) (Essumang 2010, Ooi et al. 2015, Poortvliet et al. 2015, Stewart et al. 2018). Tourism industries may also to a certain extent negatively impact individual behaviour, and if unmanaged, may affect localized use of and visitation rates to critical habitats, and may disrupt important social behaviour (Stewart et al. 2018).
