Hypophthalmichthys nobilis (Richardson, 1845)
Bighead carp
photo by Ramani Shirantha

Family:  Xenocyprididae (East Asian minnows)
Max. size:  146 cm SL (male/unsexed); max.weight: 40 kg; max. reported age: 20 years
Environment:  benthopelagic; freshwater; brackish; depth range - 0 m, potamodromous
Distribution:  Asia: China. Introduced to numerous countries and has achieved a near global distribution. However, its breeding requirements are very specialized and stocks are maintained by artificial reproduction or continuous importation. Several countries report adverse ecological impact after introduction (Ref. 1739). Often confused with Hypophthalmichthys molitrix (Ref. 59043).
Diagnosis:  Dorsal spines (total): 3-3; Dorsal soft rays (total): 7-7; Anal spines: 1-3; Anal soft rays: 12-14. Body with numerous scattered small black blotches. Keels extend from pelvic base to anus. Barbels absent. Posterior margin of last simple dorsal ray not serrated. Branched anal rays 13-14.5 (Ref. 13274). Differs from Hypophthalmichthys molitrix by having scaled keel from pelvic to anal, 240-300 long gill rakes, head length 27-35% SL, dark overall coloration, flank with dark, large, very irregularly shaped blotches, fin bases and inferior parts of head and belly yellowish (Ref. 59043).
Biology:  In its natural environment, it occurs in rivers with marked water-level fluctuations, overwinters in middle and lower stretches. Forages in shallow (0.5-1.5 m deep) and warm (over 24°C) backwaters, lakes and flooded areas with slow current. Feeds on zooplankton throughout its life under natural conditions (Ref. 120904). Breeds in very deep, very turbid and warm water above 18°C (usually 22-30°C), with high current (1.1-1.9 m/s) and high oxygen concentrations. Stocked to large rivers and almost all still water bodies as lakes and ponds. In aquaculture, adults can survive brackish water (up to 7 ppt) when released into estuaries and coastal lakes. Feeds mainly on zooplankton, but also takes algae as food (Ref. 59043). Bottom feeding fish (Ref. 6459). Undertakes long distance upriver migration at start of a rapid flood and water-level increase (in April-July depending on locality). Spawns in upper water layer or even at surface during floods. Spawning ceases if conditions change and resumes again when water level increases. After spawning, adults migrate for foraging habitats, Larvae drift downstream and settle in floodplain lakes, shallow shores and backwaters with little or no current. During autumn-winter, when temperature drops to 10°C, juveniles and adults form separate large schools and migrate downstream to deeper places in main course of river to overwinter (Ref. 59043). Marketed fresh and frozen.
IUCN Red List Status: Data deficient (DD); Date assessed: 02 September 2010 Ref. (130435)
Threat to humans:  potential pest


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