Western Central Pacific: throughout Indonesia (except southern Sumatra), Malasia (Borneo and Sabah), Papua New Guinea, Vanikoro, Pohnpei, Melanesia, and the Philippines. The range also extends through some Pacific Islands, including Guam and Fiji and along the entire northern coast of Australia.
FAO fishing area: 57, 71
Habitat and Ecology
Depth range (m): 24.1789 - 37.5
Depth range (m): 24.1789 - 37.5
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
From 1 to 85 meters.
Life History and Behavior
Molecular Biology and Genetics
Statistics of barcoding coverage: Himantura granulata
Public Records: 0
Specimens with Barcodes: 2
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
This species' preference for shallow inshore waters makes it particularly vulnerable to extensive and intensive artisanal and industrial fisheries operating throughout large areas of its range, as well as habitat destruction and pollution (B.M. Manjaji and W. White pers. obs, Vidthayanon 1997). Juveniles and sub-adults are known to be targeted in mangrove areas and destruction of mangrove forest is having a significant impact on this species (W. White pers. obs. 2007). Mangrove forests throughout Southeast Asia and large areas of the eastern Indian Ocean have been degraded (FAO 2007). In this region, ~1.9 million hectares of mangroves (or about 25% of the total 1980 area) have been lost during the last 25 years (FAO 2007). More than 90% of this loss has been caused by destruction of mangrove area in Indonesia, Pakistan, Vietnam, Malaysia and India (areas where this species occurs) through conversion of land for shrimp farms, excessive logging, conversion of land for agriculture or salt pans and degradation through oil spills and pollution (FAO 2007). Even in well-managed mangrove areas that are protected from destruction, for example, the UNESCO Biosphere Reserve in Ranong, Thailand (designated in 1997), this species may still face threats from local fisheries on which the people living in the reserve primarily depend (FAO 2007).
The Sicklefin Lemon Shark (Negaprion acutidens) occurs at similar depths to this species' preferred bathymetric range. N. acutidens is rarely observed in recent times in Indonesia due to the very high level of exploitation of inshore waters and its slow growth rate (White et al. 2006). This species is apparently uncommon compared to other large Himantura species in this region, making it particularly vulnerable. Given that H. granulata is a large stingray, probably with limiting life-history characteristics also, it is inferred that this species has also declined significantly in these areas.
The commercial gillnet fishery that targets rhynchobatid rays in the Arafura Sea, Indonesia, takes this species as retained bycatch, which is landed for human consumption (Last and Compagno 1999, W. White pers. obs. 2007). It is thought to be heavily impacted in this area, where more than 600 trawl vessels operate (W. White pers. obs. 2007). The Rhynchobatus species gillnet fishery catches large numbers of stingrays. Catches in inshore waters have declined and these vessels are having to travel longer and longer distances to sustain catches. The rhynchobatid fisheries are very intensive in this region, thus the level of exploitation is extremely high. There is also evidence that fisherman in these regions increasingly illegally fish in Australian waters (Chen 1996, W. White, unpubl. data).
Artisanal inshore fishing pressure is also very intensive off eastern India (Flewwelling and Hosch 2006). Fisheries throughout India operate on an open access basis and inshore marine species are thought to be fully or overexploited, with extensive use of illegal mesh sizes reported, and increasing ever-increasing bottom trawl effort (Flewwelling and Hosch 2006). Demersal species, such as this, suffer more fishing mortality than pelagic species on the eastern coast of India (Flewwelling and Hosch 2006). India's inshore fisheries are generally characterised by declining catch rates, declining recruitment and biomass, and a shift from regular landing patterns (Flewwelling and Hosch 2006). Although no species-specific data are available on catches, it is inferred that this species has also suffered declines as a result of high levels of inshore exploitation in these areas also.
No data or information is available on catches in the Pacific Islands, but this species may be taken as bycatch in inshore subsistence and artisanal fisheries there also.
In Australia, large specimens are caught as byatch in the Australian Northern Prawn Trawl Fishery, but the introduction of Turtle Exclusion Devices (TEDs) and other exclusion devices is thought to have greatly reduced bycatch of this species.
An elasmobranch biodiversity study in Borneo (Sabah, Malaysia) was initiated in 1996 (Fowler et al. 2002). While the monitoring surveys should continue to ascertain the status and possible threats to this species here, as well as in other portions of its range (New Guinea and Indonesia), further research should be directed at population, habitat and ecology and life history parameters due to the very high quantities taken by the large number of prawn and/or fish trawlers that operate in the region. The fishery is largely unregulated (licences being issued, but catches/ landings are not properly monitored), and presently there is no specific conservation actions in place to help address this problem.
In Australia, the use of Turtle Excluder Devices (TEDs) and Bycatch Reduction Devices (BRDs) in the Northern Prawn Fishery (NPF) has been compulsory since 2000 (Day 2000). The Northern Prawn Fishery Bycatch Action Plan (1998) also recommends that bycatch reduction targets be established and that bycatch levels be monitored (Day 2000).
Relevance to Humans and Ecosystems
The mangrove whipray or whitetail stingray (Himantura granulata) is a species of stingray in the family Dasyatidae. It is widely distributed in the Indo-Pacific region from the Red Sea to northern Australia and Micronesia. A benthic inhabitant of shallow inshore waters, juvenile mangrove whiprays favor mangrove and estuarine habitats, while adults favor sandy to rocky areas in lagoons and coral reefs. This species can be identified by its thick, oval pectoral fin disc that is dark gray above with numerous white flecks, and by its relatively short, whip-like tail that is white past the stinging spine. It grows up to 1.4 m (4.6 ft) across.
Solitary in nature, the mangrove whipray preys mainly on small, bottom-dwelling bony fishes and invertebrates. It is, like other stingrays, aplacental viviparous, with the females nourishing their unborn young via histotroph ("uterine milk"). The mangrove whipray is caught for its meat, skin, and cartilage across much of its range. The International Union for Conservation of Nature (IUCN) has assessed it as Near Threatened globally and as Endangered in Southeast Asia, where its population has declined substantially due to intensive artisanal and commercial fisheries as well as widespread habitat degradation. In particular, juvenile rays have been disproportionately targeted by fishers and affected by the large-scale destruction of mangrove forests.
Australian zoologist William John Macleay published the first scientific account of the mangrove whipray, a brief description of an immature female 86 cm (34 in) long caught off Port Moresby, Papua New Guinea, in an 1883 volume of Proceedings of the Linnean Society of New South Wales. He named it Trygon granulata, as he noted that the specimen's head and back were "covered with small granules". In 1928, Gilbert Percy Whitley moved this species to the genus Himantura. It belongs to the uarnacoides species complex, along with H. chaophraya, H. hortlei, H. lobistoma, H. pastinacoides, and H. uarnacoides. Other common names for this ray include mangrove ray, whitetail whipray, and Macleay's coachwhip ray.
The pectoral fin disc of the mangrove whipray is very thick and oval in shape, measuring 0.9–1.0 times as wide as long. The anterior margins of the disc are nearly straight and converge at a broad angle on the snout tip. The medium-sized, widely spaced eyes are immediately followed by the spiracles. Between the long, thin nostrils is a short, broad curtain of skin with a finely fringed posterior margin. The lower jaw is bow-shaped, and there are 0–5 papillae across the floor of the mouth. The teeth are arranged in a quincunx pattern and number 40–50 rows in the upper jaw and 38–50 rows in the lower jaw. There are five pairs of gill slits beneath the disc. The pelvic fins are small and narrow.
The tail is thick at the base and measures 1.5–2 times longer than the disc width. One or two dorsally positioned serrated stinging spines are located in the first third of the tail. Past the sting, the tail becomes thin and whip-like, without fin folds. The upper surface of the body and tail are roughened by tiny dermal denticles, which become larger towards the midline of the back and tail. In addition, one or two irregular rows of thorns are present along the dorsal midline from the head to the sting. The mangrove whipray is dark brown to gray above with many white dots and flecks, which become denser with increasing size. The dark coloration is due to a layer of mucus, without which the body is light orange-gray. The underside is white with small dark spots towards the disc margin. The tail abruptly becomes white past the sting. This species grows to 1.4 m (4.6 ft) across and over 3.5 m (11 ft) long.
Distribution and habitat
Although uncommon, the mangrove whipray seems to be widely distributed in the Indo-Pacific; it has been reported from the Red Sea, South Asia including the Maldives and the Andaman Islands, the Gulf of Thailand, the Malay Archipelago (except Sumatra), New Guinea and northern Australia, and various islands including Guam, Fiji, the Solomon Islands, and Micronesia. This bottom-dwelling species typically inhabits shallow water close to shore, though adults have also been recorded offshore to at least a depth of 85 m (279 ft). Juvenile rays frequent brackish habitats such as mangroves and estuaries. By contrast, adults prefer areas of sand, sand and rock rubble, or hard bottom, and are often found in lagoons or on coral reefs.
Biology and ecology
Unlike many of its relatives, the mangrove whipray is reportedly solitary in nature. It is relatively inactive during the day, often resting half-buried in sand or atop coral heads, and actively forages for food at night. The electroreceptive ampullae of Lorenzini of this species have a sensitivity of 4 nV/cm and an effective range of 25 cm (10 in), enabling it to locate buried prey. Juveniles feed mainly on small crustaceans, including prawns and crabs. Adults prey on small benthic bony fishes, including rabbitfishes, gobies, blennies, wrasses, and damselfishes, as well as invertebrates, including peanut worms, crabs, octopuses, and bivalves. As in all stingrays, the mangrove whipray is aplacental viviparous, with the developing embryos being sustained by nutrient-rich histotroph ("uterine milk") produced by the mother. The newborns measure 14–28 cm (5.5–11 in) across, and males reach sexual maturity at 55–65 cm (22–26 in) across. Known parasites of this species include the tapeworm Rhinebothrium himanturi, and another undescribed species in the same genus.
The mangrove whipray is capable of injuring a human with its venomous sting. It is occasionally caught in tangle nets and bottom trawls, and to a lesser extent on longlines; it is marketed for its meat, skin, and cartilage. Because of its inshore habitat preferences, this naturally uncommon species is highly susceptible to intensive artisanal and commercial fishing occurring across much of its range. In Southeast Asia, immature rays have been particularly affected by local fishing, as well as by habitat degradation from the widespread loss of mangrove forests. Additionally, the numbers of this species in the Arafura Sea have dropped significantly due to an Indonesian gillnet fishery targeting wedgefishes (Rhynchobatus), which involves over 600 vessels and has been increasingly operating illegally in Australian waters. These factors have led to an inferred decline of the Southeast Asian population by over 50%, leading the International Union for Conservation of Nature (IUCN) to give it a regional assessment of Endangered. The mangrove whipray is minimally threatened off northern Australia, where it is caught incidentally by the Northern Prawn Fishery (NPF) but only in small numbers following the mandatory adoption of Turtle Exclusion Devices (TEDs). As a result, the IUCN assessment for the Australian population is Least Concern. Globally, the IUCN has listed this species as Near Threatened.
- Manjaji, B.M.; White, W.T.; Fahmi; Ishihara H. (2009). "Himantura granulata". IUCN Red List of Threatened Species. Version 2010.2. International Union for Conservation of Nature. Retrieved August 24, 2010.
- Last, P.R.; Stevens, J.D. (2009). Sharks and Rays of Australia (second ed.). Harvard University Press. p. 444–445. ISBN 0-674-03411-2.
- Macleay, W. (April 1883). "Contribution to a knowledge of the fishes of New Guinea. No. III". Proceedings of the Linnean Society of New South Wales 7 (4): 585–598.
- Ishihara H.; Homma K.; Takeda Y.; Randall, J.E. (1993). "Redescription, distribution and food habits of the Indo-Pacific dasyatidid stingray Himantura granulata". Japanese Journal of Ichthyology 40 (1): 23–28.
- Manjaji-Matsumoto, B.M.; Last, P.R. (2006). "Himantura lobistoma, a new whipray (Rajiformes: Dasyatidae) from Borneo, with comments on the status of Dasyatis microphthalmus". Ichthyological Research 53 (3): 290–297. doi:10.1007/s10228-006-0350-6.
- Froese, R.; Pauly, D. (eds). (2009). Himantura granulata. FishBase, March 2009 version.
- Ferrari, A.; Ferrari, A. (2002). Sharks. Firefly Books. p. 222. ISBN 1-55209-629-7.
- Haine, O.S.; Ridd, P.V.; Rowe, R.J. (2001). "Range of electrosensory detection of prey by Carcharhinus melanopterus and Himantura granulata". Marine and Freshwater Research 52 (3): 291–296. doi:10.1071/MF00036.
- Williams, H.H. (November 1964). "Some new and little known cestodes from Australian elasmobranchs with a brief discussion on their possible use in problems of host taxonomy". Parasitology 54 (4): 737–748. doi:10.1017/S0031182000082743. PMID 14227634.