How to Identify Mottled Sculpin

To identify Mottled Sculpin (Cottus bairdi), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Highly variable, typically mottled brown, olive, or gray with darker blotches and saddles on the back and sides, providing excellent camouflage. The belly is usually lighter, often whitish or yellowish. Fins are often banded or spotted.

Scale type

none

Mouth position

terminal

Distinctive features

Large, broad, flattened head, Tapering body, compressed posteriorly, Absence of scales (smooth skin), Two dorsal fins (first spiny, second soft-rayed), Large pectoral fins, often fan-like, Preopercular spine (usually 1-4, typically 1-2 prominent ones), Pelvic fins with one spine and 3-4 soft rays

Dorsal fin

Two dorsal fins; first dorsal fin with 6-9 spines, second dorsal fin with 15-18 soft rays. The two fins are typically separated or barely joined.

Tail fin

Rounded or slightly emarginate caudal fin.

Pectoral fin

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

Distinctive fins

Pelvic fins are thoracic, located beneath the pectoral fins, with one spine and 3-4 soft rays. Anal fin with 11-14 soft rays.

Identification Tips

1. 1

   Head Shape

   Look for a noticeably large, broad, and flattened head, which is characteristic of sculpins.

2. 2

   Body Covering

   Feel for smooth, scaleless skin. This distinguishes 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 separated or only slightly connected.

4. 4

   Pectoral Fins

   Note the large, fan-like pectoral fins that are often held out to the sides.

5. 5

   Preopercular Spine

   Carefully examine the operculum (gill cover) for a sharp, often curved spine. The number and shape of these spines can help differentiate it from other sculpin species.

6. 6

   Coloration and Pattern

   The mottled brown, gray, or olive coloration with darker blotches provides excellent camouflage and is a key identifier.

Explore Mottled Sculpin