How to Identify Black Rockfish

To identify Black Rockfish (Sebastes melanops), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Typically dark gray to black on the dorsal surface, fading to a lighter gray or white on the ventral side. Often has faint, irregular dark blotches or mottling on the sides. The fins are usually dark, sometimes with lighter margins. A key identifying feature is the presence of dark spots on the dorsal fin membranes, which can be more prominent in some individuals.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Large mouth extending to or beyond the posterior margin of the eye., Lower jaw projects slightly beyond the upper jaw., Strong spines on the operculum (gill cover)., Absence of spines on the top of the head (parietal and nuchal spines are absent or greatly reduced)., Dark spots on the membranes of the spinous dorsal fin., Relatively large eyes., Maximum recorded length up to 63 cm (25 inches) and weight up to 5.2 kg (11.5 lbs), though most commonly encountered specimens are 30-50 cm (12-20 inches).

Dorsal fin

Single, deeply notched dorsal fin with 13 spines and 13-16 soft rays. The membranes between the dorsal fin spines often have distinct dark spots.

Tail fin

Caudal fin is moderately forked.

Pectoral fin

Pectoral fins are large and rounded, with 17-19 rays.

Distinctive fins

Anal fin has 3 spines and 7-9 soft rays. Pelvic fins are thoracic with 1 spine and 5 soft rays.

Identification Tips

1. 1

   Coloration

   Look for the overall dark gray to black body, often with lighter ventral side. The presence of dark spots on the dorsal fin membranes is a key diagnostic feature.

2. 2

   Jaw Projection

   The lower jaw typically projects slightly beyond the upper jaw.

3. 3

   Head Spines

   Absence or greatly reduced parietal and nuchal spines on the top of the head distinguishes it from many other rockfish species.

4. 4

   Mouth Size

   The large mouth extending to or beyond the posterior margin of the eye is characteristic.

5. 5

   Fin Ray Counts

   Counting dorsal fin spines (13) and soft rays (13-16), and pectoral fin rays (17-19) can aid in identification, especially when distinguishing from similar species.

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