How to Identify Arctic Grayling

To identify Arctic Grayling (Thymallus arcticus), look at these key features.

Physical Characteristics

Body shape

torpedo

Coloration

Generally dark purplish-blue to black on the back, fading to silvery-gray on the sides and white on the belly. Sides often have scattered black spots. The most striking feature is the large dorsal fin, which is typically iridescent with rows of reddish-orange or purple spots, edged in red or orange. Pectoral, pelvic, and anal fins are often dusky or yellowish.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Exceptionally large, sail-like dorsal fin, particularly prominent in males., Small, adipose fin present., Small mouth with fine teeth., Lateral line is complete and prominent., Scales are relatively large.

Dorsal fin

Single, very tall and long, with 17-25 rays. Extends nearly to the adipose fin in larger individuals, especially males.

Tail fin

Moderately forked.

Pectoral fin

Relatively small, positioned low on the body.

Distinctive fins

Adipose fin present, characteristic of salmonids.

Identification Tips

1. 1

   Dorsal Fin

   The most definitive feature is the exceptionally large, colorful dorsal fin, which is much taller and longer than in other salmonids. Look for iridescent colors and spotted patterns.

2. 2

   Adipose Fin

   Presence of a small, fleshy adipose fin between the dorsal and caudal fins confirms it as a salmonid, distinguishing it from non-salmonid species.

3. 3

   Mouth

   Small mouth with fine teeth, unlike the larger, more predatory mouths of many trout species.

4. 4

   Coloration

   Observe the purplish-blue to black back, silvery sides, and white belly, often with scattered black spots on the sides.

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