Actinopteri (ray-finned fishes) > Elopiformes
(Tarpons and tenpounders) > Megalopidae
Etymology: Megalops: Greek, megas, megalos = great + Greek, ops = appearance (Ref. 45335).
Environment: milieu / climate zone / depth range / distribution range
Marine; freshwater; brackish; benthopelagic; amphidromous; depth range 50 - ? m (Ref. 2847). Tropical; 34°N - 37°S, 16°E - 130°W
Indo-Pacific: Persian Gulf (Ref. 68964), Red Sea and Natal, South Africa (Ref. 3969) to the Society Islands, north to southern Korea, south to the Arafura Sea (Ref. 9819) and New South Wales. Restricted to high islands (Palau, Caroline and Mariana islands) in Micronesia. Reported as far inland as the lower Shire in Malawi and the Save-Runde junction in Zimbabwe (Ref. 7248). Widespread in the Lower Zambezi River channels up to Marromeu and in the Micelo River up to Malingapanzi (Ref. 39494). South China Sea, Taiwan Strait, and East China Sea(Ref.33302).
Length at first maturity / Size / Weight / Age
Maturity: Lm ?, range 25 - ? cm
Max length : 150 cm TL male/unsexed; (Ref. 1479); common length : 30.0 cm SL male/unsexed; (Ref. 7017); common length :45.5 cm SL (female); max. published weight: 18.0 kg (Ref. 13337); max. reported age: 44 years (Ref. 72487)
soft rays: 23 - 31. Lower jaw projects beyond snout; a bony gular plate present between the jaw bones; last fin ray of dorsal long and filamentous, directly over pelvic fins; pectoral fins low on side of body near ventral margin; abdominal pelvic fins with 9 or more rays; scales large. The modified swimbladder permits them to breathe air and thus survive in oxygen-poor water. Colour blue-green dorsally; silvery on sides (Ref. 10982). Can tolerate oxygen-poor water by `breathing' air into a lung-like air bladder.
Obligate air-breathing (Ref. 126274); Adults are generally found at sea, but young inhabit river mouths, inner bays, and mangrove forests. In freshwater, they occur in rivers, lagoons, lakes, and swampy backwaters (Ref. 2847, 44894). Tolerate a wide pH range (5.2-9.1) (Ref. 44894) and salinities from 0 to 100. Mainly diurnal (Ref. 7017). Predaceous, feeding mainly on fishes and crustaceans (Ref. 5213). Breed offshore, possibly throughout the year. Larvae are transparent and resemble larval eels (Ref. 13337), but with a forked tail (Ref. 167). Juveniles commonly enter freshwater (Ref. 44894, 48635) in clear or turbid water (Ref. 44894). Known to breath air, rising regularly to the surface to do so. Cultured in ponds, the fry being sourced from the coasts (Ref. 7050). Popular angling fish (Ref. 3969). Edible but not esteemed (Ref. 3969). Caught by gill nets, seines, and trawls, and by hook-and-line; marketed fresh and dried salted (Ref. 10982).
Whitehead, P.J.P., 1984. Megalopidae. In W. Fischer and G. Bianchi (eds.) FAO species identification sheets for fishery purposes. Western Indian Ocean fishing area 51. Vol. 3. [pag. var.]. FAO, Rome. (Ref. 3463)
IUCN Red List Status (Ref. 125652)
Threat to humans
Fisheries: minor commercial; aquaculture: commercial; gamefish: yes
Estimates based on models
Preferred temperature (Ref. 123201
): 19.8 - 27.6, mean 24.4 °C (based on 501 cells).
Phylogenetic diversity index (Ref. 82804
= 1.0020 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00741 (0.00533 - 0.01032), b=3.07 (2.98 - 3.16), in cm total length, based on LWR estimates for this species (Ref. 93245
Trophic level (Ref. 69278
): 3.5 ±0.1 se; based on diet studies.
Resilience (Ref. 120179
): Medium, minimum population doubling time 1.4 - 4.4 years (Assuming tm<=4).
Prior r = 0.57, 95% CL = 0.37 - 0.85, Based on 2 stock assessments.
Fishing Vulnerability (Ref. 59153
): Very high vulnerability (90 of 100).
Climate Vulnerability (Ref. 125649
): High to very high vulnerability (75 of 100).
Nutrients (Ref. 124155
): Calcium = 73 [41, 125] mg/100g ; Iron = 0.724 [0.433, 1.146] mg/100g ; Protein = 16.4 [13.5, 19.0] % ; Omega3 = 0.434 [0.218, 0.901] g/100g ; Selenium = 84 [41, 170] μg/100g ; VitaminA = 17.5 [6.6, 47.9] μg/100g ; Zinc = 1.13 [0.79, 1.63] mg/100g (wet weight);