Spanish mackerel (Scomberomorus commerson), also known as narrow-barred mackerel, is targeted by recreational and commercial fishers in Western Australia. Spanish mackerel can live for more than 20 years. They can grow up to about 2.4 m and more than 40 kg. Spanish mackerel have long, narrow bodies. They are dark blue along the top, becoming silvery towards the centre and underneath. They have a banded pattern, narrow dark blue or black bars running vertically along the body, narrower than the bars on their relative, the broad-barred Spanish mackerel (also called the grey mackerel).
Most commercial fishing for Spanish mackerel is done north of Geraldton, especially along the Kimberley and Pilbara coasts. Recreational fishers also target it, mainly between Perth and Dampier, for its good fighting and eating qualities.
Distribution and habitat
Spanish mackerel live throughout the Indo-West Pacific region, particularly in tropical and sub-tropical waters. In Western Australia, they’re found from Cape Leeuwin northwards to the Northern Territory border.
They are offshore, pelagic (surface-dwelling) fish and live around offshore and coastal reefs.
Research suggests the mackerel in WA’s northern waters don’t move more than 100 kilometres along the coast. In southern waters, they are thought to migrate over hundreds of kilometres, following the warmer waters of the Leeuwin Current.
Adults ‘aggregate’ (form groups) to feed and ‘spawn’ (release sperm and eggs) in coastal areas. At other times, they probably disperse but remain in the same region. This dispersal may include some movement into deeper shelf waters.
Small mackerel up to five years old tend to school and appear to be more mobile than larger fish.
Illustration © R. Swainston/www.anima.net.au