Blackblotched Stingray

The round ribbontail ray, also known as the blotched fantail ray (Taeniurops meyeni), is a stingray species belonging to the Dasyatidae family. It is widely distributed across the nearshore waters of the tropical Indo-Pacific and the islands of the eastern Pacific. This ray is predominantly found inhabiting lagoons, estuaries, and reefs, residing at depths ranging from 20 to 60 meters. Notable for reaching a size of 1.8 meters in width, it possesses a distinctive thick, round pectoral fin disc, covered with small tubercles, and a relatively short tail with a prominent ventral fin fold. Its upper surface is marked by a unique pattern of light and dark mottles, and it features a characteristically black tail.

Primarily nocturnal, the round ribbontail ray exhibits both solitary and social behaviors. It is an active predator, feeding on small benthic molluscs, crustaceans, and bony fishes. Reproduction in this species is aplacental viviparous, with embryos initially nourished by yolk, followed by histotroph secretion by the mother. Litters can comprise up to seven pups. While the ray is generally non-aggressive, it can utilize its venomous tail spine defensively if provoked, and it has been implicated in at least one fatal incident. It holds particular value among ecotourist divers and recreational anglers. However, owing to its slow reproductive rate, the species is threatened by both targeted and bycatch commercial fishing activities and habitat degradation, leading the International Union for Conservation of Nature (IUCN) to classify it as Vulnerable.

The species is named in honor of Franz Julius Ferdinand Meyen (1804-1840), a physician and botanist responsible for collecting or supplying the type specimens.

Morphologically, the round ribbontail ray's pectoral fin disc is thicker and broader than its length, with a smoothly rounded outer edge. Medium-sized eyes are positioned ahead of larger spiracles. A short, broad curtain of skin, featuring a finely fringed trailing edge, stretches between its oval nostrils. The mouth is wide and curved, with subtle furrows at its corners and equipped with seven papillae on its floor, the outermost being smaller and spaced apart. The upper jaw comprises 37–46 tooth rows, while the lower jaw includes 39–45. Teeth are small with pronounced grooves and form a dense quincunx arrangement. The pelvic fins are small and narrow; the tail, shorter than the disc width, carries one or two long serrated spines. The tail's base is broad, tapering past the spine to a deep ventral fin fold extending to the end. The disc and tail's surfaces are coarse, covered with small granules, accompanied by a row of sharp tubercles along the midline.

The dorsal coloration ranges from light to dark gray, brown-gray, or purplish, intensifying towards the fin margins, complemented by a pattern of darker mottling and occasional white speckles or streaks. The tail beyond the spine is uniformly black, while the underside is creamy-white with darker fin margins and additional spots. Adult rays display more complex coloration than juveniles. As one of the largest stingray species, it can achieve dimensions of up to 1.8 meters across, 3.3 meters in length, and 150 kilograms in weight.

The round ribbontail ray inhabits a wide geographical range within the Indo-Pacific, recorded from 🇿🇦 South Africa's KwaZulu-Natal (🇿🇦 South Africa) up the East African coast to the 🌊 Red Sea. Its range encompasses 🇲🇬 Madagascar, the Mascarenes, extending east through the 🇮🇳 Indian subcontinent to Southeast Asia and 🇫🇲 Micronesia, reaching as far north as Korea and southern 🇯🇵 Japan and as far south as 🇦🇺 Australia. It has also been observed at 🇨🇨 Cocos Island (🇦🇺 Australia) and the Galápagos Islands, with potential dispersal to Central America.

Typically settling close to shore, the ray occupies depths of 20-60 meters, though reports of it have been at depths up to 439 meters. It favors environments with sandy or rubble bottoms, often near coral and rocky reefs, sometimes entering estuaries. The species is typically motionless during daylight hours, often found near vertical structures, in caves, or under ledges. It may be solitary or congregate in groups, frequently accompanied by fish such as jacks or cobia that benefit from the ray's foraging efforts.

The lifecycle of the round ribbontail ray remains largely undefined. However, like other stingrays, it is aplacental viviparous, with embryos sustained initially by yolk and subsequently by histotroph from the mother. Reproductive aggregations have been noted at 🇨🇨 Cocos Island (🇦🇺 Australia), particularly following the advent of La Niña, which introduces cooler water temperatures. During these events, a single female may be pursued by numerous males. Females can bear up to seven pups, birthing possibly in summer near 🇿🇦 South Africa, though precise maturation details are only known for males, who reach sexual maturity at 1.0-1.1 meters disc width.

The round ribbontail ray is a prominent attraction for divers due to its size and striking appearance. However, when harassed, it can inflict serious injuries with its venomous tail spine. Conservation concerns for this species are pronounced due to its limited reproductive capacity and the persistent degradation of its coral reef habitats from agricultural runoff and destructive fishing practices, such as blast fishing. It is caught across its range by commercial and recreational fisheries using lines, trawls, and other gear types. 🇮🇩 Indonesian waters present significant fishing pressure, where the species is targeted by tangle netters, longliners, and trawlers operating off Java, Bali (🇮🇩 Indonesia), 🇵🇬 New Guinea, and Lombok, with all captured specimens sold for consumption.