How to Identify Smooth Dogfish

To identify Smooth Dogfish (Mustelus canis), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Dorsal surface typically gray to grayish-brown, sometimes with a bronze tint; ventral surface is white or off-white. Juveniles may have faint dark spots that fade with age.

Scale type

placoid

Mouth position

subterminal

Distinctive features

Smooth skin (lacks prominent dermal denticles, hence 'smooth'), Blunt, rounded teeth arranged in pavement-like plates, adapted for crushing shells, Two dorsal fins of similar size, Anal fin present, No spines associated with dorsal fins

Dorsal fin

Two dorsal fins, nearly equal in size. The first dorsal fin originates over or slightly behind the pectoral fin axil. The second dorsal fin is slightly smaller than the first and originates over the pelvic fins.

Tail fin

Heterocercal caudal fin, with the upper lobe significantly longer than the lower lobe, and a distinct subterminal notch.

Pectoral fin

Moderately large and triangular.

Distinctive fins

Anal fin present, located anterior to the second dorsal fin.

Identification Tips

1. 1

   Skin Texture

   Run your hand along the skin; it feels noticeably smoother than most other sharks due to very small, non-overlapping dermal denticles.

2. 2

   Teeth

   Examine the teeth; they are blunt, flattened, and pavement-like, designed for crushing, not tearing. This is a key differentiator from spiny dogfish or other sharp-toothed sharks.

3. 3

   Dorsal Fins

   Note the absence of spines in front of the dorsal fins, unlike the Spiny Dogfish (Squalus acanthias).

4. 4

   Anal Fin

   Presence of an anal fin is a distinguishing feature from dogfish species in the family Squalidae (e.g., Spiny Dogfish).

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