Spotted Eagle Ray

Aetobatus narinari (Euphrasen, 1790)

syn. Aetobates narinari, Aetobatis latirostris, Aetobatis narinari, Raja narinari, Stoasodon narinari

3 m230 kg1-79 mVenomousEndangered

1956

The spotted eagle ray (Aetobatus narinari) is a cartilaginous fish belonging to the eagle ray family, Aetobatidae. Traditionally, it has been found in tropical regions worldwide, including the Atlantic, Pacific, and 🌊 Indian Oceans. However, recent authorities have redefined its distribution, limiting it to the Atlantic, including the Caribbean and 🌊 Gulf of Mexico. Other populations are now recognized as the ocellated eagle ray (A. ocellatus) and the Pacific white-spotted eagle ray (A. laticeps). Spotted eagle rays are typically solitary, but can occasionally be seen swimming in groups. They reproduce through ovoviviparity, with the female retaining the eggs and releasing miniature versions of the parent.

This ray species can be identified by its dark dorsal surface covered in white spots or rings. It possesses venomous, barbed stingers near the base of its relatively long tail, just behind the pelvic fins. Spotted eagle rays primarily feed on small fish and crustaceans, and have been observed digging with their snouts in search of buried food in the sandy sea bed. These rays are known for their ability to leap out of the water, and there have been reported incidents of them jumping into boats, occasionally resulting in unfortunate outcomes. Spotted eagle rays are preyed upon by various shark species. Currently, they are classified as near threatened on the IUCN Red List. They are primarily fished in Southeast Asia and Africa, mainly for commercial trade and aquariums. The species is protected in the Great Barrier Reef.

Spotted eagle rays have flat, disk-shaped bodies that are deep blue or black with white spots on top, while their underbelly is white. They have distinctive flat snouts resembling a duck's bill. Their tails are longer than those of other ray species and may contain 2-6 venomous spines behind the pelvic fins. The pectoral disk, which resembles wings, features five small gills on its underside. Mature spotted eagle rays can grow up to 5 meters (16 ft) in length. The largest individuals can have a wingspan of up to 3 meters (10 ft) and weigh as much as 230 kilograms (507 lb).

During mating, one male, or sometimes multiple males, will pursue a female. Upon approaching her, the male will use his upper jaw to grab her dorsum. He will then roll the female over by grasping one of her pectoral fins. This positioning allows the male to insert a clasper into the female, connecting their ventral sides. The mating process typically lasts for 30-90 seconds. Spotted eagle rays develop ovoviviparously, with the eggs being retained in the female and hatching internally as the pups feed off a yolk sac. After a gestation period of one year, a female ray will give birth to a maximum of four offspring. Newly born pups have a pectoral disk diameter ranging from 17-35 centimeters (6.7-13.8 in). The rays reach maturity within 4 to 6 years.

Spotted eagle rays primarily feed on bivalves, crabs, whelks, and other benthic infauna. They also consume molluscs, including the queen conch, and crustaceans, particularly malacostracans. Additionally, they feed on echinoderms, polychaete worms, hermit crabs, shrimp, octopuses, and small fish. These rays possess a specialized tooth structure shaped like chevrons, which enables them to crush the hard shells of molluscs. Their jaws have calcified struts that support them and prevent damage when breaking through the shells of hard prey. Spotted eagle rays also exhibit unique behavior by digging with their snouts in the ocean sand. This action creates a cloud of surrounding sand and leads to sand discharge from their gills. Research indicates that there are no notable differences in feeding habits between males and females or among individuals from different regions.

Traditional distributions indicate that spotted eagle rays inhabit tropical regions worldwide, including the Indo-Pacific, western 🌊 Pacific Ocean, 🌊 Indian Ocean, and western Atlantic Ocean. They are commonly found in shallow coastal waters near coral reefs and bays, with depths ranging up to 80 meters (262 ft). These rays can be observed in warm and temperate waters globally. In the western Atlantic Ocean, they are present along the eastern coast of the 🇺🇸 United States, the Gulf Stream, the Caribbean, and the southern part of 🇧🇷 Brazil. In the 🌊 Indian Ocean, their range extends from the 🌊 Red Sea to 🇿🇦 South Africa and eastward to the Andaman Sea. In the Western 🌊 Pacific Ocean, they can be found near 🇯🇵 Japan and north of 🇦🇺 Australia. Spotted eagle rays are also present throughout the Hawaiian Islands in the Central 🌊 Pacific Ocean. In the Eastern 🌊 Pacific Ocean, their range includes the Gulf of 🇺🇸 California and Puerto Pizarro, which encompasses the Galapagos Islands. These rays are most commonly sighted in bays and reefs, often swimming in schools near the water's surface. They are capable of covering long distances in a day. However, recent taxonomic revisions have split the species into three distinct populations: the true spotted eagle ray (A. narinari) in the Atlantic, the ocellated eagle ray (A. ocellatus) in the Indo-Pacific region, and the Pacific white-spotted eagle ray (A. laticeps) in the East Pacific.

It is worth mentioning that in Disney Pixar's films Finding Nemo (2003) and Finding Dory (2016), Mr. Ray is portrayed as a spotted eagle ray and serves as a teacher to Nemo and his friends.

Why it's threatened

Biological resource use

Intentional use: (subsistence/small scale) [harvest] · Unintentional effects: (subsistence/small scale) [harvest] · Unintentional effects: (large scale) [harvest] · Persecution/control

Whitespotted Eagle Rays occur in coastal inshore waters where fishing pressure is substantial through portions of the species' range, particularly in the Gulf of Mexico, Caribbean Sea, and Eastern Central and Southeast Atlantic Ocean along the coast of Africa. The species often enters estuarine waters where fishing pressure is high. The swimming behaviour of this species makes it susceptible to a range of fishing gear throughout the water column, especially inshore gillnet fisheries, which are intensive throughout most of its range. This species is taken in target artisanal gillnet fisheries and industrial shrimp trawl fisheries.

First, in the Northwest and Western Central Atlantic, artisanal directed fisheries for Whitespotted Eagle Ray are not well described throughout its range but are known to exist in Mexico (Cuevas-Zimbrón et al. 2011), Cuba (Cuba NPOA-Sharks 2015), and Venezuela (Tagliafico et al. 2012). In Caribbean Colombia, artisanal fisheries are widespread and lack management, and there is also a shallow-water shrimp trawl fishery for which stocks have collapsed; this ray is taken there using gillnet, longline, and trawl gears (P. Mejía-Falla and A. Navia unpubl. data 2018);. In Venezuela, commercial and artisanal fisheries are intense, they lack management, and have exhibited peaks in catches followed by declines, indicative of sequential overfishing (Mendoza 2015), and this species is targeted in artisanal fisheries there (Tagliafico et al. 2012). Declining annual catch rates have been demonstrated for fisheries in Mexico and Venezuela (Cuevas-Zimbrón et al. 2011, Tagliafico et al. 2012).

Second, in the Southwest Atlantic, artisanal fisheries are intense across much of coastal Atlantic South America, and there are largely unmanaged commercial trawl and longline fisheries in many areas. Groundfish fisheries on the Brazil-Guianas shelf were already fully over-exploited by 2000; these fisheries are multi-gear, multi-species, and multinational, with vessels crossing national maritime borders (Booth et al. 2001). Despite some areal closures and the implementation of a total allowable catch of target species, there is now a diminished effort and number of vessels in operation there (Diop et al. 2015). In northwestern Brazil, artisanal fisheries pressure is high and 44% of target stocks were likely to be overfished by the end of the 2000s (Vasconcellos et al. 2011). The combination of intense and unmanaged artisanal and commercial fishing in that area has led to the disappearance of several elasmobranch species in the region, including Largetooth Sawfish (Pristis pristis), Smalltooth Sawfish (Pristis pectinata), Daggernose Shark (Isogomphodon oxyrhynchus), and Smalltail Shark (Carcharhinus porosus) (Charvet and Faria 2014, Lessa et al. 2016, Reis-Filho et al. 2016, Santana et al. 2020). In northeastern and eastern Brazil, artisanal fisheries are intense, gillnetting is the predominant artisanal gear, fishers there report that stocks are overexploited, and other sharks have been depleted (Guebert-Bartholo et al. 2011, Reis-Filho et al. 2016). In southern Brazil, the trawl fishery began in the 1960s and entered a period of rapid expansion in the 1990s and 2000s, resulting in over 650 vessels fishing at depths of 20–1,000 m (Port et al. 2016). Artisanal fisheries are also intense, and 58% of stocks targeted by artisanal fishers are overexploited, half of those having collapsed (Vasconcellos et al. 2011).

Third, in the Eastern Central Atlantic, sharks and rays were already being exploited by semi-industrial fisheries in the 1950s (Walker et al. 2005). While these fisheries gradually collapsed, the demand for dried salted shark meat (for export to Ghana) and shark fins in the 1980s drove the development of artisanal targeted shark fishing across much of the region (Diop and Dossa 2011, CCLME 2016, Seto et al. 2017, Moore et al. 2019). Over the years, this has expanded into targeted shark and ray fisheries across many countries and is likely increasing fishing pressure on this species (Walker et al. 2005, Diop and Dossa 2011). Furthermore, this has led to population reductions of many species of sharks and rays including the local extinction of sawfishes (family Pristidae) from West African coastal waters and several species of wedgefishes from their northern range in Mauritania and Senegal (e.g., False Shark Ray (Rhynchorhina mauritaniensis) from the Parc National du Banc d’Arguin) (Walker et al. 2005, Kyne et al. 2020). Sharks and rays are still targeted in a number of countries with artisanal fishers using drift gillnets and demersal set gillnets with large mesh sizes (e.g., Mauritania, Nigeria, Ghana, Cameroon; M. Diop, I. Seidu, A. Tamo, and A.B. Williams unpubl. data 2020).

In general, fishing effort and the number of fishers has intensified in recent decades across most of the range of this species. For example, in West Africa, reports indicate that the diversity and average body size of many important commercial coastal, demersal, and pelagic fishery species have markedly declined with many stocks now considered to be overexploited (FAO 2000, Srinivasan et al. 2012, Polidoro et al. 2016, CCLME 2016). Trawl surveys carried out across the Gulf of Guinea from 1977 to 2000 showed a decline in fish biomass of approximately 50% (Brashares et al. 2004). Further, the total demersal biomass of inshore stocks is estimated to have declined by 75% since 1982 (Meissa and Gascuel 2015). The direct cause of decline for many of these stocks has been attributed to overcapacity within both the industrial and artisanal fisheries and destructive fishing practices (GCLME 2006, CCLME 2016). Overall, between 1950 and 2010, the total artisanal fishing effort increased by 10-fold with an estimated 252,000 unregulated artisanal and 3,300 industrial vessels (mostly distant water fleets from Europe and East Asia operating under ‘access agreements’ that take sharks and rays as bycatch) operating in this region by 2010 (Walker et al. 2005, Diop and Dossa 2011, Belhabib et al. 2018).

Given their naturally molluscan diet, negative interactions with shellfish farming are episodic and anecdotally reported in the Northwest Atlantic (McEachran and Carvalho 2002, M. Ajemian pers. obs. 2019). Confirmed interactions generally stem from molluscan culture operations in the Indo-Pacific such as have also been reported for conspecifics such as A. narutobiei in Japan (Yamaguchi et al. 2005). While never implemented for Whitespotted Eagle Ray in the United States of America (USA), predator culling programs have been considered for other myliobatid species in the USA, notably Bat Ray (Myliobatis californicus) off California (Gray et al. 1997) and Cownose Ray (Rhinoptera bonasus) in Chesapeake Bay and elsewhere in the USA (Grubbs et al. 2016).

Whitespotted Eagle Ray is a popular public aquarium species and is collected for the marine aquarium trade (Swider et al. 2017). Since this species routinely enters estuaries this species may also be threatened by pollution, dredging, and habitat loss.

Threat classification from the IUCN Red List.