Short mackerelRAB

Rastrelliger brachysoma
19.8 cm FL

Characteristic features:

  • 2 small keels on either side of caudal peduncle
  • Adipose eyelids covering front and rear of eye
  • 30–48 gill rakers on lower limb of first gill arch
  • Gill rakers long and visible from side of head when mouth open
  • 5–6 dorsal and anal finlets
  • Head length equal to or less than body depth
  • Body very deep, its depth at posterior margin of opercle 3.7–4.3 times FL

Colour:

Silvery white below, silvery greenish above with fine dark spots. Pectoral and pelvic fins dusky, caudal fin yellow.

Size:

Up to 40 cm TL, and up to at least 2 kg in weight (Manacop 1995 in 1).

Distribution:

East Indian & Western Central Pacific.

View FAO distribution map

Habitat:

An inshore epipelagic, neritic species that tolerates reduced salinity entering estuarine habitats. Found within a temperature range of 20–30°C and usually between 15–200 m depth.2

Biology:

Feeds primarily on micro zooplankton with high phytoplankton content. Forms schools with similar sized conspecifics. In the Javan sea, length where 50% of individuals become mature is between 15–18 cm FL, equivalent to 7.5 months old.3 Estimated maximum age is at least 2 years.4

Indonesian fisheries:

An important commercial species in the Philippines. Caught by native purse seining, in fish corrals and by dynamiting.

Similar species:

Rastrelliger faughni
Island mackerel
Rastrelliger faughni
Rastrelliger faughni differs in having a slender body, its depth at posterior portion of opercle 4.9–6 times in fork length (vs. deep, 3.7–4.3); head length greater than body depth (vs. equal to or less than body depth); gill rakers visible from side of head when the mouth open (vs. not visible) and 21–26 gill rakers on the lower limb of first gill arch (vs. 30–48).

 

Rastrelliger kanagurta
Indian mackerel
Rastrelliger kanagurta differs in having a moderately deep body, its depth at posterior portion of opercle 4.3–5.2 times in fork length (vs. deep, 3.7–4.3); a black spot near lower margin of pectoral fins (vs. no black spot) and 30–46 gill rakers on lower limb of the first gill arch (vs. 30–48).

 

Scomber australasicus
Blue mackerel
Scomber australasicus differs in having teeth present on the roof of mouth (palatine teeth) in single or double rows (vs. absent); first anal-fin spine stiff and strong (vs. thin, rudimentary); many oblique wavy dark lines on dorsal surface, pearl white below where wavy, lines become broken, giving faintly speckled appearance (vs. Silvery white below, silvery greenish above with fine dark spots and 25–35 gill rakers on the first gill arch (vs. 30–48).

External links:

FishBase
The IUCN Red List of Threatened SpeciesTM

References

1.
Jones S, Rosa H. Synopsis of biological data on Indian mackerel, Rastrelliger kanagurta, (Cuvier) 1817 and short bodied mackerel, Rastrelliger brachysoma (Bleeker) 1851. 1965;
2.
Al Sakaff H, Esseen M. Occurrence and distribution of fish species off Yemen (Gulf of Aden and Arabian Sea). Naga, the ICLARM Quarterly. 1999;22(1):43–7.
3.
Sudjastani T. Species of Rastrelliger in the Java Sea, their taxonomy, morphometry and population dynamics. University of British Columbia; 1974.
4.
Tandog-Edralin D, Ganaden S, Fox P. A comparative study of fish mortality rates in moderately and heavily fished areas of the Philippines. FAO Fisheries Report (FAO). 1988;