Abbreviated Life History of Kelp Greenling
(Hexagrammos decagrammus)

Kelp Greenling; Photo by Steve Lonhart of Simon/NOAA

The kelp greenling is one of the most conspicuous fishes in rocky nearshore habitats, occurring often in and around kelp beds. The kelp greenling is in the family Hexagrammidae, and shares a taxonomic relationship with lingcod. The male and female look so different that they were first described as separate species. The body color is variable in both sexes, ranging from light gray to brown. Males have large irregular blue patches anteriorly. Females are uniformly covered with smaller reddish-brown to golden spots and have yellowish-orange fins.

Distribution, Stock Structure and Migration

Populations range from La Jolla, California to the Aleutian Islands in Alaska. They are rare in southern California though. Kelp greenlings are not known to migrate; adults are often territorial, particularly during spawning season.

Age and Growth

Kelp greenlings grow faster than most nearshore fishes during their first three years. They have been aged to a maximum of 12 years. Total lengths corresponding to the male and female ages were 15 inches and 17.4 inches, respectively. The largest recorded size is 21 inches.

Reproduction, Fecundity and Seasonality

Approximately one-third of all male kelp greenling are sexually mature at age two, while half of all males are mature by age four, at an average total length of 11.6 inches. About one-half to two-thirds of all females kelp greenling are sexually mature at age four, at an average total length of 11.6 inches. In general, 50 percent of all kelp greenling are mature at 5 years (9.5 inches).

Predator/Prey Relationships

Kelp greenling larvae prey on a wide variety of planktonic organisms, including fish larvae and eggs. For most of the year, juveniles and adults consume a variety of prey that is consistently available in the habitat, including crabs, shrimp, snails, chiton, abalones, octopi, fish, fish eggs, and algae. There are brief periods when organisms such as juvenile fishes or herring spawn become exceptionally abundant, and kelp greenling shift their food habits to take advantage of these opportunities. The primary predators of adult greenling are lingcod and harbor seals.

Competition

Based on co-occurrence with adult and juvenile kelp greenling, demersal fishes associated with kelp beds and reef structure likely to compete with kelp greenling for food and space would include lingcod, cabezon, and rockfish species such as grass, kelp, gopher, black-and-yellow, and China.

Critical Habitat

Kelp greenling range in depth from the intertidal to approximately 500 ft deep but are more common at depths of 150 ft or less. Juveniles and adults both frequent subtidal habitats in or around rocky reef areas, in kelp beds, and any area with dense algal growth. They have also been documented on sandy bottom.

Fishery and Status of Stocks

Kelp greenling is very popular in the live fish fishery, making up nearly 45% of the live-fish business at some markets. There are no estimates of abundance for kelp greenling in California.

Information on this page was originally presented in the Nearshore Fishery Management Plan (these profiles updated July, 2010).

Kelp Greenling