Creature Feature: Kelp Greenling and Rock Greenling

greenlingsThe kelp greenling and rock greenling are very closely related. Kelp greenling are most common in central and northern California. They may be found southward to La Jolla, but are quite rare south of Point Conception. Rock greenling may be found southward to Point Conception, but are rare south of San Francisco. Both species prefer relatively shallow water habitats along rocky coasts, around jetties, and in kelp beds, and so probably compete directly for space and food. The maximum recorded depth for kelp greenling is 150 ft.

Distinguishing Characteristics

  • Male kelp greenling: Dark gray to brown, front half with numerous sky-blue spots, each surrounded by a ring of rust-colored spots. Very small flap of skin (cirrus) over each eye and halfway to the dorsal fin.
  • Female kelp greenling: Gray-brown, uniformly covered with round reddish-brown spots. Inside of mouth yellowish. Very small cirrus over each eye and halfway to the dorsal fin.
  • Rock greenling (both sexes): Reddish-brown with darker mottling, often with large bright red blotches on sides. Inside of mouth bluish. Cirrus over each eye.

Life History & Other Notes
Both kelp and rock greenlings feed on various sea worms, crustaceans, and small fishes. They can be caught using cut pieces of fish, clams, mussels, shrimp, squid, worms, and crab backs for bait, or try feathered jigs tipped with squid. Once hooked, greenlings can be difficult to land because of their habit of entangling anglers’ lines in rocks or kelp.

 Kelp Greenling and Rock Greenling Quick Facts

Scientific Names:

Hexagrammos decagrammus (kelp greenling); Hexagrammos lagocephalus (rock greenling)

Other Common Names: sea trout, rock trout, kelp trout

Range & Habitat: Most frequently in central and northern California, in rocky habitats and kelp forests

Length & Weight: Kelp greenling to 21 in.; rock greenling to 24 in.

Life Span: Kelp greenling to 16 years; rock greenling to 11 years

Excerpt from the California Finfish and Shellfish Identification Book.

Single copies of the book are available to California residents free of charge by emailing a request to