Environment: milieu / climate zone / depth range / distribution range
Ecology
Marine; benthopelagic; depth range 0 - 120 m (Ref. 86942). Tropical; 32°N - 34°S, 30°E - 134°W
Indo-West Pacific: Red Sea, South Africa, Thailand to Western Australia.; north to Japan (Yaeyama Is.), to Solitary Is., Australia as far east as French Polynesia and the Hawaiian Is. Reported in the Atlantic (Canary and Cape Verde islands) but this species may be restricted more or less to the Indian and Western Pacific only (McEachran, pers.comm. 03/10).
Length at first maturity / Size / Weight / Age
Maturity: Lm 371.1, range 324 - 390 cm
Max length : 500 cm WD male/unsexed; (Ref. 82755); max. reported age: 31 years (Ref. 97313)
Short description
Identification keys | Morphology | Morphometrics
This species is characterized by the following: disc approximately 2.2-2.4 times as broad as it is long, the maximum disc width size approximately 550 cm; slender whip-like tail approximately 123% of disc length if intact; no distinct caudal spine or cartilaginous mass at base of tail; some specimens have small hump at the base of the tail on the dorsal surface, while others have a slight depression and groove on the dorsum of the tail immediately posterior to the posterior margin of the dorsal fin; small, knob-like dermal denticles evenly distributed on both the dorsal and ventral surfaces, with ventral surface having slightly larger denticles; dental ligament with small cusped teeth on the lower jaw measuring roughly 22% of total disc length, approximately 6-8 rows, 142-182 files across entire width of the tooth band; total tooth counts of 900-1500 for entire tooth band; top jaw lacks rows of enlarged denticles (Ref. 82755).
Adults are commonly sighted inshore, within a few kilometers of land; found around coral and rocky reefs as well as along productive coastlines with consistent upwelling, tropical island groups, atolls and bays (Ref. 82755). Maximum movement recorded is >500,000 m (Ref. 97317). Known aggregations include sites in Hawai'i, Mozambique, Maldives, Ryukyu Island, Yap Island, Indonesia, eastern and western Australia (Ref. 82755). Gestation period is 12-13 months. Major food consists of planktonic organisms and probably small bony fishes (Ref. 114953).
Young may tend to follow large objects such as their mother (Ref. 205).
Last, P.R., W.T. White, M.R. de Carvalho, B. Séret, M.F.W. Stehmann and G.J.P. Naylor, 2016. Rays of the world. CSIRO Publishing, Comstock Publishing Associates. i-ix + 1-790. (Ref. 114953)
IUCN Red List Status (Ref. 130435)
Threat to humans
Harmless
Human uses
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Estimates based on models
Preferred temperature (Ref.
123201): 24.3 - 29, mean 27.8 °C (based on 1274 cells).
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5005 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01000 (0.00244 - 0.04107), b=3.04 (2.81 - 3.27), in cm total length, based on all LWR estimates for this body shape (Ref.
93245).
Trophic level (Ref.
69278): 3.5 ±0.5 se; based on size and trophs of closest relatives
Resilience (Ref.
120179): Very Low, minimum population doubling time more than 14 years (tmax>31; tm = 3-8; Fec =1).
Fishing Vulnerability (Ref.
59153): Very high vulnerability (85 of 100).
Nutrients (Ref.
124155): Calcium = 5.54 [0.80, 100.50] mg/100g; Iron = 0.474 [0.044, 5.786] mg/100g; Protein = 19.2 [13.9, 24.5] %; Omega3 = 0.0832 [, ] g/100g; Selenium = 90.7 [16.3, 541.7] μg/100g; VitaminA = 6.64 [0.42, 83.54] μg/100g; Zinc = 0.545 [0.030, 6.451] mg/100g (wet weight);
