Johnius borneensis (Bleeker, 1851)
Sharpnose hammer croaker
Alakaak,  Abo,  Abu,  Alakaak,  Alakak,  Bugor,  Dulama,  Ilak,  Lagis,  Simu,  Tangdulan
Johnius borneensis
photo by Randall, J.E.

Family:  Sciaenidae (Drums or croakers)
Max. size:  34.8 cm TL (male/unsexed)
Environment:  benthopelagic; freshwater; brackish; marine; depth range 0 - 132 m
Distribution:  Indo-West Pacific: Persian Gulf eastward to southern China and Taiwan and northern and northeastern Australia and New Guinea.
Diagnosis:  Dorsal spines (total): 10-12; Dorsal soft rays (total): 27-32; Anal spines: 2-2; Anal soft rays: 7-8. Snout rounded but not swollen or projecting; mouth large, oblique; upper jaw extending backward below posterior half of eye; no barbel on chin; teeth in narrow bands, well differentiated into large and small in both jaws, but none canine-like; gill rakers slender, about half length of gill filaments at angle of arch, 9 to 15 on lower limb. Second anal spine moderately long, 24 to 42 % of head length. Scales on head cycloid (smooth). Swim bladder hammer-shaped, the first pair of arborescent appendages entering head beyond transverse septum and sending a palmate branch to the front of pectoral arch. Sagitta (large earstone) with a tadpole-shaped impression, the head of which has its long axis lying obliquely to that of sagitta and the tail expanded and deepened as a hallow cone connected with the head by narrow groove.
Biology:  Inhabits shallow coastal waters, estuaries, and rivers. In India, matures at the size of 14 to 16 cm TL; attains an average size of 15.8 cm TL, 20.6 cm TL, and 24 cm TL, at the end of 1 year, 1.5 years and 2 years, respectively. Juveniles prefer crustaceans and as they grow , show piscivorous tendency (Ref. 9772). Marketed fresh and dried salted (Ref. 3490).
IUCN Red List Status: Least Concern (LC); Date assessed: 27 September 2018 Ref. (130435)
Threat to humans:  harmless
Country info:   
 


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