Decapterus macarellus


Mackerel scad MSD
Characteristic features:
Colour:

Blueish green above, silver below, a small black blotch on upper edge of operculum. Pelvic and anal fins pale to whitish, caudal fin dusky.

Size:

Up to 45 cm TL.

Distribution:

Circumglobal in tropical waters.

Habitat:

Pelagic and schooling, found mostly in open waters from 40 to 200 m depth.

Biology:

Feeds primarily on small planktonic invertebrates. Forms schools. In waters off southern Japan, size where 50% of individuals are mature is estimated at 25.8 cm FL for both males and females, corresponding to 2 years old. Maximum age is estimated at least 8 years.1

Indonesian fisheries:

Caught with purse seines and trawls.

Similar species:

Decapterus kurroides
Redtail scad

Decapterus kurroides

Decapterus kurroides differs in having a straight part of lateral line with no scales (vs. 18–39 scales); pectoral fins long, tips extending to, or slightly beyond second dorsal-fin origin (vs. considerably shorter, not reaching near second dorsal-fin origin) and oral valve (membrane) at symphysis of upper jaw dusky or transparent (vs. conspicuously white in adults).

Decapterus macrosoma
Shortfin scad

Decapterus macrosoma

Decapterus macrosoma differs in having the posterior end of upper jaw concave above, rounded and produced below (vs. posterior end of upper jaw straight above, straight to slightly concave below); straight part of lateral line with 14 to 29 scales (vs. 18–39 scales); pectoral fins shorter, tips falling considerably short of level with second dorsal-fin origin (vs. longer, falling just short, or slightly beyond of level with second dorsal-fin origin) and oral valve (membrane) at symphysis of upper jaw dusky or transparent (vs. conspicuously white in adults).

Decapterus russelli
Indian scad

Decapterus russelli

Decapterus russelli differs in having a smaller eye (vs. larger); the straight part of lateral line with 0–4 scales (vs. 18–39 scales); curved part of lateral line with 0–4 scutes (vs. none); pectoral fins long, tips extending to, or slightly beyond second dorsal-fin origin (vs. considerably shorter, not reaching near second dorsal-fin origin) and oral valve (membrane) at symphysis of upper jaw dusky or transparent (vs. conspicuously white in adults).

Decapterus tabl
Roughear scad

Decapterus tabl

Decapterus tabl differs in having a straight part of lateral line with 4–12 scales in (vs. 18–39 scales); oral valve (membrane) at symphysis of upper jaw dusky or transparent (vs. conspicuously white in adults) and rear margin of opercular membrane slightly serrated (vs. smooth).

External links:
References:
  1. Shiraishi T, Tanaka H, Ohshimo S, Ishida H, Morinaga N. Age, growth and reproduction of two species of scad, Decapterus macrosoma and D. macarellus in the waters off southern Kyushu. Japan Agricultural Research Quarterly: JARQ [Internet]. 2010;44(2):197–206. Available from: http://www.jircas.affrc.go.jp