How to Identify Slimy Sculpin

To identify Slimy Sculpin (Cottus cognatus), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Variable, typically mottled brown, gray, or olive on the dorsal surface, fading to a lighter, often whitish, ventral side. Dark saddles or blotches may be present along the back and sides. Fins are often banded or spotted.

Scale type

none

Mouth position

terminal

Distinctive features

Large, flattened head with a wide mouth, Tapering body, compressed posteriorly, Absence of scales, skin is smooth and often feels slimy, Two dorsal fins, the first spiny and the second soft-rayed, Large, fan-like pectoral fins, Preopercular spine (typically 1-4, often blunt or embedded)

Dorsal fin

Two dorsal fins; the first with 7-10 spines, the second with 15-18 soft rays. The two fins are typically separate or barely joined.

Tail fin

Rounded or slightly emarginate caudal fin.

Pectoral fin

Large, fan-like, with 13-16 rays, extending beyond the origin of the anal fin.

Distinctive fins

Pelvic fins are thoracic, with one spine and 3-4 soft rays, often with a dark band.

Identification Tips

1. 1

   Body and Head Shape

   Look for a large, flattened head that is noticeably wider than the body, which tapers significantly towards the tail. The eyes are typically set high on the head.

2. 2

   Skin Texture

   Feel for smooth, scaleless skin. This is a key characteristic distinguishing it from many other freshwater fish.

3. 3

   Dorsal Fins

   Observe the two distinct dorsal fins. The first is spiny and shorter, while the second is longer and soft-rayed. They are usually separate or only slightly connected.

4. 4

   Preopercular Spine

   Carefully check the preopercle (bone just in front of the gill cover) for a spine. Cottus cognatus typically has 1-4 spines, which can be blunt or embedded and may require careful examination.

5. 5

   Coloration and Pattern

   Note the mottled brown/gray/olive coloration with darker blotches or saddles, which provides excellent camouflage against rocky substrates.

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