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Mackerel Scad

Mackerel Scad

Decapterus Macarellus

Quick Facts

Scientific name Decapterus Macarellus

Other names Round Scad, Opelu Scad, Galunggong

Size Up to 46 cm (18.11 in)

Weight Up to 1 kg (2.2 lb)

Distribution

Habitat & AU Distribution Deeper coastal and oceanic waters amongst reef edges and islands - pelagic

Depth Range 10 - 400 m (1,300 ft)

Interesting Info

The Mackerel Scad is a small, fast schooling fish with a slender, mackerel-like body and a silvery shine.
It grows to about 46 cm (18 in) long, with most caught between 20–35 cm (8–14 in).
In Australia it occurs off Western Australia, the Northern Territory, Queensland, and New South Wales, especially around offshore reefs and warmer waters.
Globally it has a circumtropical distribution—found across the Indo–West Pacific from East Africa and the Red Sea to Japan, Australia, and the Pacific Islands, and also in the Atlantic and eastern Pacific, including Mexico and Hawaii.
Its name comes from its resemblance to mackerel, with a more elongated body and a bluish-green back that fades to silvery sides.
They form huge schools in midwater, often mixing with other scads and small pelagic fishes.
Mackerel Scad feed on plankton, small crustaceans, and tiny fish, capturing prey while swimming rapidly with mouths open.
Spawning occurs offshore, with eggs and larvae drifting in ocean currents before juveniles move into shallower coastal areas.
They are short-lived, usually surviving 3–5 years, but grow quickly to escape predators.
Larger predators like tuna, mackerel, and billfish feed heavily on them, making them an important link in the food chain.
Divers and snorkellers may spot shimmering schools near reefs, with their blue-green backs reflecting sunlight.
In Hawaii, they are called “ʻOpelu” and are an important traditional food fish.

Species Interaction

Recreational & Commercial Fishing, Snorkelling & Diving

For anglers, Mackerel Scad are valued mainly as baitfish for larger predators like tuna, marlin, and giant trevally. In many Pacific islands and Asian countries, they are also eaten fresh, salted, or dried. Divers and snorkellers may encounter them in large, glittering schools flashing blue and silver.

Scientific Classification

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Order: Carangiformes

Family: Carangidae

Genus: Decapterus

Species: Decapterus macarellus

Conservation Status

The Mackerel Scad is listed as Least Concern by the IUCN. It is abundant across its global range, supporting both local fisheries and marine food webs. However, heavy local fishing can reduce numbers in some island nations.

Fish Taste Quality

Mackerel Scad are an important food fish in many Pacific communities, eaten grilled, dried, or in soups. The flesh is soft, slightly oily, and mild in flavour, though it spoils quickly if not handled well.

Taste Rating: 3/5