How to Identify Slimey Mackerel

To identify Slimey Mackerel (Scomber australasicus), look at these key features.

Physical Characteristics

Body shape

torpedo

Coloration

Dorsal surface iridescent blue-green, fading to silvery white on the flanks and belly. Distinctive pattern of wavy, dark, irregular lines or spots on the upper sides, extending below the lateral line. Often has a series of small, dark spots along the lower flanks.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Two widely separated dorsal fins, followed by 5-6 finlets., Anal fin followed by 5-6 finlets., Small, cycloid scales covering the body., A well-developed lateral line., Large eyes., Caudal fin deeply forked.

Dorsal fin

Two dorsal fins; the first with 9-10 spines, the second with 12 soft rays, followed by 5-6 finlets.

Tail fin

Deeply forked, lunate caudal fin, characteristic of fast-swimming pelagic fish.

Pectoral fin

Short, triangular pectoral fins, typically located high on the body.

Distinctive fins

Pelvic fins are small and located beneath the pectoral fins. Anal fin has 1 spine and 11-12 soft rays, followed by 5-6 finlets.

Identification Tips

1. 1

   Dorsal Pattern

   Look for the distinctive wavy, dark lines or spots on the iridescent blue-green dorsal surface, extending below the lateral line. This is a key differentiator from other mackerel species.

2. 2

   Finlets

   Count the finlets behind the second dorsal and anal fins; S. australasicus typically has 5-6 finlets after each, a characteristic of Scombridae.

3. 3

   Body Shape

   Observe the streamlined, torpedo-shaped body, indicative of a fast-swimming pelagic fish.

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