Blue mackerelMAA

Scomber australasicus
29.0 cm FL

Characteristic features:

  • 2 small keels on either side of caudal peduncle
  • Teeth present on roof of mouth
  • Adipose eyelids cover front and rear of eye
  • 10–13 dorsal fin spines
  • Second dorsal fin anterior of anal fin
  • First anal-fin spine stiff and strong

Colour:

Blueish green above with many oblique wavy dark lines, pearl white below with wavy, broken lines giving faintly speckled appearance.

Size:

Up to 45 cm TL, and up to 1.4 kg in weight.

Distribution:

Found in subtropical waters of the Indo-Pacific.

Habitat:

Epipelagic, found at depths between 87–200 m.

Biology:

Feeds primarily on plankton by filtering small crustaceans such as copepods form the water column. Adults also feed on small fish and squid. Forms large schools with similarly sized fishes such as other mackerel and sardine. This species displays variable life history parameters depending on location. In Australia, age of first maturity is estimated at 2 years,1 and length where 50% of individuals become mature is estimated at 28.6 and 23.6 cm FL for females and males respectively.2 In Japan, blue mackerel larger than 31.0 cm FL were considered mature.3 This species is larger and longer lived in New Zealand, maturing at 3 years, corresponding to 28 cm FL,4 and has an estimated maximum age of 24 years.5 Blue mackerel are batch spawners, with the spawning period varying with location. In waters off southern Australia, spawning occurs between November and April, with a spawning frequency ranging between 2–11 days. Females can produce ~70,000 eggs per batch.2

Indonesian fisheries:

Caught by encircling nets and purse seining.

Similar species:

Rastrelliger spp.
Chub mackerel
Rastrelliger brachysoma
Rastrelliger brachysoma
Rastrelliger spp. differ in having a first anal-fin spine thin and rudimentary (vs. stiff and strong); 1 or 2 horizontal rows of spots on both sides of back (vs. many oblique wavy dark lines) and no teeth present on roof of mouth (teeth present).

External links:

FishBase
The IUCN Red List of Threatened SpeciesTM

References

1.
Stevens JD, Hausfeld HF, Davenport S. Observations on the biology, distribution and abundance of Trachurus declivis, Sardinops neopilchardus and Scomber australasicus in the Great Australian Bight. Commonwealth Scientific and Industrial Research Organization, Marine Laboratories; 1984.
2.
Rogers P, Ward T, McLeay L, Lowry M, Saunders R, Williams D. Reproductive biology of blue mackerel, Scomber australasicus, off southern and eastern Australia: suitability of the Daily Egg Production Method for stock assessment. Marine and Freshwater Research. 2009;60(2):187–202.
3.
Yukami R, Ohshimo S, Yoda M, Hiyama Y. Estimation of the spawning grounds of chub mackerel Scomber japonicus and spotted mackerel Scomber australasicus in the East China Sea based on catch statistics and biometric data. Fisheries Science. 2009;75(1):167–74.
4.
Manning MJ, Marriott PM, Taylor PR. The length and age composition of the commercial catch of blue mackerel (Scomber australasicus) in EMA 1 & 7 during the 2004–05 fishing year. New Zealand Fisheries Assessment Report. 2007;13:41.
5.
Morrison MA, Taylor PR, Marriott PM, Sutton CP. An assessment of information on blue mackerel (Scomber australasicus) stocks. New Zealand Fisheries Assessment Report. 2001;44:26.