Description
Medium to large fishes, body elongate, fusiform, to rather short and deep, compressed to slightly rounded; mouth inferior to strongly oblique; teeth usually small, villiform, set in bands, outer row in upper jaw and inner row in lower jaw often larger; a pair of canine-like teeth may be present near tip of upper jaw; roof of mouth, vomer and palatine toothless. Conspicuous pores (rostral pores) usually present on tip (upper pore) and lower margin (marginal pores) of snout, and on chin (mental pores); lower jaw with a short barbel. Dorsal fin long, continuous, with a deep notch between anterior (spinous) and posterior (soft) portions; anterior portion with 7-13 spines, posterior portion with one spine and 18-40 soft rays; anal fin with 1-2 spines and 6-13 soft rays; pectoral fins moderately long, with 14-18 long rays; caudal fin emarginate, truncate, rhomboidal to asymmetrically pointed. Swimbladder well developed, oval or carrot-shaped, often with complicated appendages. Drumming muscles usually developed only in males. Otolith (sagitta) large, with a tadpole-shaped sulcus on its inner surface. Scales ctenoid on body, cycloid scales often present on snout, nape and circumorbital region. Pored lateral line scales extending to hind margin of caudal fin.
Distribution
Tropical and warm temperate, coastal waters from shoreline to upper slopes (250-300 m); over muddy or sandy mud bottom, and among rocks in some cases; occurring in the Atlantic, Pacific, and Indian Oceans. They feed mainly on smaller fishes, crustaceans and other bottom invertebrates; move to midwater or deeper slope area, when bottom temperature drops below 16-18° C. Juveniles and subadults often enter estuaries and coastal lagoons; spawning offshore or along the coast, often forming aggregations; usually with a prolonged spawning season from late spring to autumn. Important commercial fishes, may constitute more than 30% bottom-trawl catches in certain fishery grounds, also sought for by sport fishermen.
Recent revisions: Collignon, 1959 (eastern Atlantic and Mediterranean only); Dardignac, 1961; Trewavas, 1962; Trewavas, 1964; Trewavas, 1973; Longhurst, 1969; Chao, 1981.
Species included on this CD-rom:
Johnius macropterus (Bleeker)