Chap Chap

This species is distinguished by the following characters: body very deep, compressed, with a strongly humped back; body depth 1.7-1.9 times in standard length; mouth pointing downward when protracted; gill rakers short and fleshy, less than 1/2 length of corresponding gill lamellae, total gill rakers on first gill arch 18-22; head and breast scaleless; tubed scales on lateral line 61-66. Colour of adults, back greyish, belly silvery and many parallel close-set faint bars on back; usually a dark brown saddle on caudal peduncle; axil of pectoral fins grey to black; margin of soft dorsal fin black; both caudal-fin lobes with broad dusky margins; pectoral, pelvic, and anal fins colourless to yellowish. In juveniles (5-7 cm TL), thin, closely arranged, grey vertical lines descending from back to about midheight; membrane between anal-fin spines conspicuously yellow; posterior margin of caudal-fin lobes pale yellow and dusky; other fins hyaline; snout dotted black (Ref. 47581).

Amphidromous. Refers to fishes that regularly migrate between freshwater and the sea (in both directions), but not for the purpose of breeding, as in anadromous and catadromous species. Sub-division of diadromous. Migrations should be cyclical and predictable and cover more than 100 km.Characteristic elements in amphidromy are: reproduction in fresh water, passage to sea by newly hatched larvae, a period of feeding and growing at sea usually a few months long, return to fresh water of well-grown juveniles, a further period of feeding and growing in fresh water, followed by reproduction there (Ref. 82692).

Dorsal spines (total): 8; Dorsal soft rays (total): 15 - 16; Analspines: 3; Analsoft rays: 14 - 15

Found in river mouths and muddy inshore areas. Sometimes enters freshwater (Ref. 2847). Between February and May, adult less abundant in the estuary (Ref. 4959). Feeds on zooplankton and benthic invertebrates (Ref. 11889).

Found in river mouths and muddy inshore areas (Ref. 2847, 37816), often in mangrove areas (Ref. 48635). Adults are coastal inhabitants found on soft bottoms, usually between depths of 10-70 meters. Juveniles are commonly found in mangrove estuaries and tidal creeks, sometimes entering the lower reaches of freshwater streams (Ref. 44894). Adults move in schools. Frequently ascend into freshwater reaches of rivers (Ref. 12693). Active by day (Ref. 12693). Feed on polychaetes, small crustaceans, small fishes (Ref. 30573) and worms (Ref. 12693). Important food fish in the tropics (Ref. 4376). Caught near the bottom with bottom trawls, set nets, push nets, dip nets, and beach seines. In Indian waters, schools near the surface during April-May when caught with drift gill nets. Larger specimens sorted for human consumption and marketed fresh or dried-salted, but surplus fish used to feed ducks, converted to fishmeal, or discarded (Ref. 47581).

fisheries: minor commercial; aquaculture: commercial; price category: high; price reliability: questionable: based on ex-vessel price for species in this genus