How to Identify Sculpin

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

Physical Characteristics

Body shape

elongated

Coloration

Highly variable, typically mottled brown, grey, or olive with darker blotches and bands, providing excellent camouflage against rocky or gravel substrates. Undersides are usually lighter.

Scale type

none

Mouth position

terminal

Distinctive features

Large, broad, flattened head, Large mouth with small, conical teeth, Absence of scales (skin is smooth or covered with prickles/spines), Two dorsal fins (first spiny, second soft-rayed), Large, fan-like pectoral fins, Pelvic fins thoracic, with one spine and 3-5 soft rays, Preopercular spine(s) present on the cheek

Dorsal fin

Two dorsal fins; the first is spiny (6-11 spines), and the second is soft-rayed (11-20 rays). The two fins may be separate or slightly joined at the base.

Tail fin

Rounded or slightly emarginate caudal fin.

Pectoral fin

Large, fan-like, and rounded, typically with 13-18 rays.

Distinctive fins

Pelvic fins are small, located beneath the pectoral fins, and have one spine and 3-5 soft rays. Anal fin is soft-rayed (8-16 rays) and similar in shape to the second dorsal fin.

Identification Tips

1. 1

   Head Shape

   Look for a disproportionately large, broad, and flattened head compared to the rest of the body.

2. 2

   Body Covering

   Feel for the absence of scales; the skin is either smooth or covered with small prickles or spines, not true scales.

3. 3

   Dorsal Fins

   Observe the two distinct dorsal fins, the first being spiny and the second soft-rayed.

4. 4

   Pectoral Fins

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

5. 5

   Preopercular Spine

   Examine the cheek area for one or more sharp spines on the preopercle (bone covering the gill).

6. 6

   Coloration and Pattern

   Their mottled, cryptic coloration helps them blend into their benthic environment.

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