How to Identify Blue Runner

To identify Blue Runner (Caranx crysos), look at these key features.

Physical Characteristics

Body shape

torpedo

Coloration

Dorsal side is typically dark blue to blue-green, fading to silvery-white on the flanks and belly. A small, distinct black spot is usually present on the upper operculum (gill cover). Fins are often dusky or yellowish.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Streamlined, fusiform body, Laterally compressed, Large, forked caudal fin, Prominent scutes (bony plates) along the posterior part of the lateral line, Small black spot on the operculum

Dorsal fin

Two dorsal fins; the first with 8 spines, the second with 1 spine and 23-27 soft rays. The anterior rays of the second dorsal fin are elongated.

Tail fin

Deeply forked, powerful caudal fin with long lobes.

Pectoral fin

Long, falcate (sickle-shaped) pectoral fins, extending beyond the origin of the anal fin.

Distinctive fins

Anal fin with 2 detached spines followed by 1 spine and 19-22 soft rays. Pelvic fins are relatively small.

Identification Tips

1. 1

   Body Shape

   Look for the sleek, torpedo-like body, characteristic of fast-swimming pelagic fish.

2. 2

   Coloration

   Note the dark blue-green back and silvery sides, with the distinctive small black spot on the gill cover.

3. 3

   Lateral Line Scutes

   Observe the prominent, bony scutes along the posterior section of the lateral line, a key feature of Carangidae.

4. 4

   Pectoral Fins

   The long, sickle-shaped pectoral fins are a good indicator.

5. 5

   Fin Ray Counts

   For precise identification, count the soft rays in the second dorsal fin (23-27) and anal fin (19-22).

Explore Blue Runner