Classification / Names
Common names | Synonyms | Catalog of Fishes (gen., sp.) | ITIS | CoL | WoRMS | Cloffa
Elasmobranchii (sharks and rays) > Myliobatiformes
(Stingrays) > Dasyatidae
Etymology: Urogymnus: Greek, oura = tail + Greek, gymnos = naked (Ref. 45335). More on author: Bleeker.
Environment: milieu / climate zone / depth range / distribution range
Freshwater; brackish; demersal; potamodromous (Ref. 51243). Tropical; 25°N - 20°S
Asia and Oceania: Mekong and Chao Phraya basins; also from eastern Borneo, New Guinea and northern Australia.
Length at first maturity / Size / Weight / Age
Maturity: Lm ?, range 110 - ? cm
Max length : 240 cm WD male/unsexed; (Ref. 27732); max. published weight: 600.0 kg (Ref. 6871)
(total): 0. Absence of ventral and dorsal skin folds on the tail, and the broad greyish to blackish marginal band on the ventral surface of the disc. The dorsal surface of the disc is brown (Ref. 27732). Spiral valve with 21 turns; dorsal surface with uniform brown or grey coloration (Ref. 12693). Lacking caudal fin; with long whip-like tail (Ref. 43281).
Inhabits sandy bottoms in estuaries and large rivers (Ref. 12693). Feeds on benthic invertebrates (Ref. 12693) and fishes (Ref. 32457). Ovoviviparous (Ref. 50449). Caught occasionally by demersal gillnet and longline fisheries operating in riverine and estuarine areas. Utilized for its meat and possibly its cartilage (Ref.58048). Marketed fresh, with large individuals being sold in cut pieces by the kilogram (Ref. 12693). Size reaches to about 500 cm TL. Threatened due to over harvesting and pollution (Ref. 58490).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Exhibit ovoviparity (aplacental viviparity), with embryos feeding initially on yolk, then receiving additional nourishment from the mother by indirect absorption of uterine fluid enriched with mucus, fat or protein through specialised structures (Ref. 50449). Distinct pairing with embrace (Ref. 205). Young are born at about 30 cm disc width (Ref. 6871).
Rainboth, W.J., 1996. Fishes of the Cambodian Mekong. FAO species identification field guide for fishery purposes. FAO, Rome, 265 p. (Ref. 12693)
IUCN Red List Status (Ref. 120744)
CITES (Ref. 115941)
Threat to humans
Fisheries: minor commercial; aquaculture: experimental; aquarium: potential
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates of some properties based on models
Phylogenetic diversity index (Ref. 82805
= 0.5156 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01738 (0.00555 - 0.05444), b=3.03 (2.78 - 3.28), in cm Total Length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245
Trophic Level (Ref. 69278
): 3.5 ±0.37 se; Based on food items.
Resilience (Ref. 69278
): Very Low, minimum population doubling time more than 14 years (Assuming Fec<10).
Vulnerability (Ref. 59153
): Very high vulnerability (90 of 100) .