Throughout its distribution, the Coach Whipray is taken as target and bycatch in coastal fisheries by demersal trawl, tangle nets, set nets, gill nets, droplines, longlines, and Danish seine (White et al. 2006, Blaber et al. 2009). In Indonesia, small-scale fisheries comprise most (~90%) of fisheries production (Tull 2014). In some regions, effort by these small-scale fisheries has tripled when taking population growth into account (Ramenzoni 2017). Sharks and rays are an important resource in Indonesia and are the main livelihood for some communities (Sadili et al. 2015). Indonesia catches the highest number of chondrichthyans in the world with the catch of rays rising as shark fisheries collapse. In 2003, rays comprise over 50% of chondrichthyan landings, up from 32% in 1981 (White et al. 2006). Stingrays contribute the most (more than 95%) to elasmobranch catch by Danish seines (cantrang) operating in the Java Sea (Fahmi et al. 2008). Intensive longline and gillnetting occurs throughout the Malacca Strait, with some mini-trawl operations and Danish seines operating throughout Kalimantan and the Java Sea (Fahmi unpubl. data 2020). Thus, the actual level of exploitation of this species could be extremely high throughout the Indonesian portion of its range.
In Malaysia, fisheries significantly contribute to the national economy through employment opportunities, and protein supply (A. Bin Ali unpubl. data 2020). Fishing effort in Malaysia has been increasing since 1950 across subsistence, artisanal, and industrial fisheries (Pauly et al. 2020). The number of vessels across all sectors has more than doubled from 22,800 vessels in 1950 to 50,150 vessels in 2014 (Zeller and Pauly 2016). However, the substantial increase over this period has been in engine power which has dramatically increased by ~30 fold (Pauly et al. 2020). Consequently, fisheries were fully exploited by the late 1970s (Teh and Teh 2014). Nevertheless, fish consumption continues to rise and most (~85%) comes from the Malaysian Exclusive Economic Zone (EEZ) (Fowler et al. 2002, A. Bin Ali unpubl. data 2020). Small-scale inshore fisheries provide the main supply for local consumption. Fisheries operating within 30 nautical miles (nm) from the coast contribute 85% to the total marine fish landings with vessels <70 Gross Tonnage (GT). In waters beyond 30 nm from the coast, trawls, and purse seines are the main fishing gears, deployed from large vessels >70 GT. These fisheries have contributed significantly to habitat destruction and reduced abundances of all commercially important fishes in the area (Teh et al. 2009).
In Thailand, this species is caught primarily in two gears: otter board-trawl (70% of catch) and paired trawl (16–25% of catch) (Krajangdara 2019). The gulf coast is considered one of the most overfished regions of the world due to the rapid industrialization of their fishing fleet (Sylwester 2014). The number of Thai trawlers peaked in 1989 at ~13,100 boats (Poonnachit-Korsieporn 2000), which was reflected in the catch-per-unit-effort (CPUE) which declined from >300 kg per hour in 1963 to 20–30 kg per hour in the 1990s (Poonnachit-Korsieporn 2000). Fisheries in Thailand have been moving to deeper water for decades due to the overexploitation of the coastal region (Sylwester 2014).
In the Philippines, the Coach Whipray is taken as bycatch in commercial and small-scale municipal fisheries with multiple fishing gears including demersal and pelagic trawl, purse seine, longline, hook and line, gillnet, set net, and traps. Commercial fisheries are generally >3GT vessels and small-scale municipal fisheries are generally <3GT vessels or not requiring vessels and are <15 km from shore. All incidental catch in Philippines appears to be retained as discards are virtually non-existent (Palomares and Pauly 2014). In the Philippines, the demand for seafood has always been high with per capita fish consumption increasing over the last two decades to 34.1 kg per capita in 2013 (Helgil 2020). The fishing fleet in the Philippines rapidly expanded in the 1960s and 1970s as small-scale artisanal fisheries became motorized and evolved into commercial fisheries. By the 1980s, overfishing was apparent throughout the Philippines, but government and foreign aid continued to subsidize motorizing of artisanal vessels into the late 1990s (Palomares et al. 2014). The commercial fleet operating in the Philippine EEZ tripled from the 1960s (2,100 vessels) to 2014 (6,400 vessels) and mostly use trawls, bagnets, purse seines, ringnets, longlines, and ‘baby trawlers’ of ~ 3GT (Palomares et al. 2014). Fishing shifted from mainly inshore demersal to offshore pelagic species during the late 1980s (Palomares and Pauly 2014). ‘Baby trawlers’ operate intensively in inshore waters and in waters less than 13 m deep, waters traditionally reserved for small-scale artisanal fishers (Palomares et al. 2014). The small-scale fleet increased ten-fold from 1950 (30,500 vessels) to the mid-1990s ( 338,700 vessels) and while the fleet size has since remained relatively stable, the effort in terms of engine power has continued to rise, as has the number of subsistence vessels (Pauly et al. 2020). Small-scale fishers mostly use cast nets, gillnets, hook and line, spear, traps and pots, and barriers (Palomares et al. 2014).
Sharks and rays are captured by a wide range of gears in Myanmar. Since 2004, sharks and rays are largely taken as incidental catch in coastal gillnets, trawls (for fish or shrimp), longlines targeting mackerels, and hookah divers spearing at night (mostly catching rays and carpet sharks) (Howard et al. 2015, Mizrahi et al. 2020). These inshore fisheries are relatively small-scale and include many subsistence level fishers. At times since 1950, significant numbers of foreign vessels have operated in Myanmar waters targeting fish and shrimp. These vessels have operated in both inshore and offshore areas. Offshore fishing that incidentally catches sharks and rays is carried out by a large commercial fleet of mostly trawlers, purse seiners, and longliners. International Labour Organisation (2015) estimated the number of vessels participating in the small-scale inshore fishery to be about 26,000 in 2013, with about 50% of them unpowered. The number of locally operated larger offshore vessels numbered 2,846 in 2013, having increased nearly 30% since 2009. Foreign fishing vessels numbered 153 in 2013, but had historically been much higher. Foreign vessels were banned in 2014.
Bangladesh has a substantial artisanal fishing fleet that operates throughout the coastal regions. In 2017–2018 there were 67,669 vessels reported to be operating (DoF 2018). All benthic rays in Bangladesh are targeted with non-baited demersal longlines (1–10 km) with 10,000–30,000 hooks that operate in 5–40 m depth (A.B. Haque unpubl. data 2020). Anecdotal reports indicate a steep decline in rays over the past 10 years (Ullah et al. 2014, A.B. Haque unpubl. data 2020). This decline is concurrent with steep increases in artisanal and subsistence fisheries effort (Pauly et al. 2020). The artisanal fishing vessels land >90% of the total marine catch and generally operate inshore at depths of 0–40 m but can operate to 80 m (Hoq et al. 2014, A.B. Haque unpubl. data 2020). The marine capture fisheries of Bangladesh exploit a complex, multi-species resource, and can be subdivided into subsistence (small-scale, non-commercial), artisanal (small-scale, commercial), and industrial (large-scale, commercial) fisheries sectors. Among the commercial catch, more than 90% is landed by artisanal fishing vessels, while industrial fisheries contribute around 6% to the total landed catch (Ahmad 2004). Each trawling vessel is equipped with trawl gear as well as demersal set longline gear to target shark and rays. There has been an increase in fishing vessels over the past 10 years. Many trawlers in the southwest region of the country will go out to sea for 5–10 days and sometimes more than 15 days and return with greater landings of larger ray species (A.B. Haque unpubl. data 2020). It is believed that there may be a number of nursery areas around coastal Bangladesh. Sharks and rays landed in the pre-monsoon season are often pregnant and near term. This period overlaps with significant fishing pressure (A.B. Haque unpubl. data 2020).
In Sri Lanka, fishing takes place all around the coast, but primarily within the continental shelf. The potential yield from coastal fish resources has been estimated at 250,000 t per year with 170,000 t per year from coastal pelagic species and 80,000 t from demersal species (Blindheim and Foyn 1980). Coastal fisheries still account for about 67% of the marine fishes caught, but there are some uncertainties regarding further expansion of coastal fishing activities (Wijayaratne 2001). Survey catch rate of sharks and rays was 105 kg per hr in 1980 from the Fritjof Nansen survey (Table VI, Sivasubramaniam and Maldeniya 1985). Approximately 28,000 fishing crafts are operating in Sri Lanka. Out of this, 87% of crafts operate in the coastal fishery which consists of traditional non-motorised crafts and fiberglass reinforced plastic boats with inboard engines. Both types of vessels are generally day boats, not venturing far from the coast (Wijayaratne 2001). Over 28,000 fishing crafts are now operating, including multi-day boats that remain at sea sometimes for 20-25 days (NARA 2003).
In India, juvenile rays are found in estuaries and high fishing effort, particularly with stake and doll nets, occurs in this habitat. The majority of the geographic distribution of this species in the region overlaps with intense coastal fisheries. There are approximately 24,554 trawl vessels operating in the Indian part of the range (CMFRI 2010). The shallow depth distribution means this species is unlikely to have a depth refuge. There has been a significant increase in coastal fishing effort and power over the past 30 years (just over one generation length). There were about 6,600 trawlers operating in the Indian state of Gujarat in the early 2000s (Zynudheen et al. 2004). This number increased to 11,582 trawlers in 2010 (CMFRI 2010). Furthermore, there are over 13,400 gill netters operating along the west coast, with many other types of net gear also deployed in coastal areas (CMFRI 2010). In Pakistan waters, about 2,000 trawlers operate in shelf waters, targeting shrimp in shallow waters and fish in outer shelf waters (M. Khan pers. comm. 6 February 2017). There is also a recent increase in fishing pressure on large stingrays, like this species, due to increased demand for export of frozen wings to Thailand and Malaysia in the past six years (M. Khan pers. comm. 11 December 2020). In Iran, there is increasing fishing effort with the number of fishermen increasing from 70,729 in 1993 to 109,601 in 2002 (Valinassab et al. 2006).
In the Western Indian Ocean, marine fisheries catches reported to FAO have increased over the past 30 years but have levelled off since 1999 suggesting stocks are fully fished. There is concern for serial depletion with the number of species landed near-doubling from only 85 in 1971 to 152 reported in 2000 (van der Elst et al. 2005). More than 60 million people reside within 100 km of the coast of the Western Indian Ocean and there is great dependence on marine resources for food and employment (van der Elst et al. 2005). Almost 3 million people are directly dependent on artisanal fishing for their livelihood along the shores of East Africa and Madagascar (van der Elst et al. 2005). In contrast to many other regions of the world, where industrial fisheries with high-technical gear predominate, fishers in the Western Indian Ocean operate primarily at the subsistence and artisanal level. For example, in Tanzania, no more than 5% of fishers are active in industrial fishing, the other 95% being artisanal (van der Elst et al. 2005). Artisanal catches are underreported and most small-scale, artisanal, and subsistence coastal fisheries within the Western Indian Ocean are considered to be fully- or overexploited, especially where they are found close to population centers. Over the last ten years, the number of underexploited fisheries in the coastal zone has tended to decline and such fisheries are now an exception (FAO 2006, Pierce et al. 2008).
There is a large amount of Illegal, Unreported, and Unregulated (IUU) fishing in the Indo-Pacific region with reported catch estimated to represent only 0.9–19.4% of the true catch (Tull 2014). In some areas, including near Marine Protected Areas (MPAs), IUU catch of sharks was estimated to equal 77% of the reported catch, indicating much higher levels of depletion (Varkey et al. 2010).
This species’ preference for estuarine and inshore coastal waters means it is also threatened by extensive habitat degradation, including pollution and clearing, and destructive fishing practices. Large coastal areas, in particular mangroves, have been lost in Indonesia and Malaysia through land conversion for urban development, shrimp farms, and agriculture. Across Indonesia and Malaysia from 1980 to 2005, the area of mangroves was reduced by >30% (FAO 2007, Polidoro et al. 2010).
