How to Identify Dark-banded rockfish

To identify Dark-banded rockfish (Sebastes inermis), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Highly variable, typically dark brown to reddish-brown or olive-green dorsally, fading to lighter shades ventrally. Often exhibits irregular dark bands, blotches, or mottling on the body and fins. Some individuals may have a reddish tint. The peritoneum is typically black.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Relatively smooth head, lacking prominent spines on the nasal, preocular, supraocular, postocular, tympanic, and parietal bones., Absence of a strong occipital pit., Lower jaw slightly projecting., Large eyes., Lateral line scales typically number 40-50., Pectoral fins are large and fan-like.

Dorsal fin

Single dorsal fin with 13-15 strong, venomous spines and 12-15 soft rays. The spinous portion is deeply notched from the soft-rayed portion.

Tail fin

Caudal fin is truncate to slightly emarginate.

Pectoral fin

Pectoral fins are large, rounded, and contain 16-19 rays.

Distinctive fins

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

Identification Tips

1. 1

   Head Spines

   Unlike many other rockfish species, Sebastes inermis has a relatively smooth head with very few or absent prominent spines on the nasal, preocular, supraocular, postocular, tympanic, and parietal bones. This is a key distinguishing feature.

2. 2

   Coloration and Pattern

   Observe the body coloration, which is often dark brown to reddish-brown or olive-green with irregular dark bands or blotches. The black peritoneum is also a useful internal identifier.

3. 3

   Dorsal Fin

   Count the dorsal fin spines (13-15) and soft rays (12-15). Note the deep notch between the spinous and soft-rayed portions.

4. 4

   Lower Jaw

   The lower jaw typically projects slightly beyond the upper jaw.

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