Overview

Key Features:

A juvenile Sebastes mystinus has light blue body with brick red zig-zags. Adults are blue with dark mottling, and have 2 or more sloped bars from the eye back to the gill cover. Rear edge of anal fin is straight.

Similar Species:

Black rockfish (Sebastes melanops)
Deacon rockfish (Sebastes diaconus)

Primary Common Name:

Blue rockfish

General Grouping:

Bony fishes

Geographic Range:

Central Oregon to Baja Sur, Mexico.

Blue rockfish, as recently re-described, occur from Newport, Oregon to Punta Santo Tomas, Baja California.

Intertidal Height:

0 to 0 feet (0 to 0 meters)

Notes:

Does not occur in the intertidal.

Subtidal Depth Range:

Minimum Depth: 0 meters or 0 feet
Maximum Depth: 549 meters or 0 feet

Notes:

Listed to 549 m, but could be confounded by observations of a similar species. Typically in central CA adult blue rockfish swim in schools above the bottom, often in kelp forests at depths from 5-25 m.

Habitats:

bay (rocky shore), bay (sandy shore), kelp forest

Notes:

Blue rockfish lives most commonly in southern Oregon and California waters. Records of blue rockfish in the Gulf of Alaska and Bering Sea probably refer to the related dusky rockfish, Sebastes ciliatus, or the recently described deacon rockfish.

Schooling Sebastes mystinus are usually found off the bottom over reefs, kelp beds, and pinnacles from 0-500 m deep, with the majority of fish living near the surface down to 90 m. In kelp beds, adults form both loose and compact aggregations and are commonly mixed with black rockfish, Sebastes melanops, and can also be seen with olive rockfish, Sebastes serranoides. Juveniles are pelagic and can be found in the shallow kelp canopy, rocky areas and nearshore sand-rock interface in less than 10 m of water.

Abundance:

Relative Abundance:

Common to abundant

Species Description:

General:

Sebastes mystinus is in the class Actinopterygii (ray-finned fishes), order Scorpaeniformes (scorpionfishes and flatheads), Sebastidae family (rockfishes, rockcods, and thornyheads), and the Sebastinae subfamily. There were two recognized color patterns in blue rockfish: blue-sided and blue-blotched. Genetic data indicate that these are distinct groups (see publications by Burford et al.). A 2015 paper by Frable et a. examines morphological features and genetic data to determine if the two 'types' of blue rockfish are really the same species or two species. Frable et al. (2015) introduce a new species, which separates the two 'types' into two species, Sebastes mystinus (blue rockfish) and S. diaconus, the deacon rockfish. For fish >10 cm, the deacon rockfish is most easily distinguished from blue rockfish by a brownish-blue to blue-gray trunk with distinct lighter blue-gray speckles, whereas the steel-blue to greenish-blue body coloration and large, dark blotches indicate blue rockfish. Here is a quote from the paper: "Differentiation of the 2 species without the use of genetic techniques can be challenging, but the trunk coloration provides the most obvious difference between the 2 species. Sebastes mystinus is generally lighter colored, gray-blue to green-blue, and has a blotched pattern on the body, whereas S. diaconus is generally darker, blue to blue-brown, and has a distinct speckling pattern on the trunk." So blotched = blue rockfish Dense speckles or solid = deacon rockfish

Distinctive Features:

Sebastes mystinus has a fusifrom, deep, elongate and compressed body. The coloring is dark bluish black to gray with light blue mottling. The pectoral fins are large and the dorsal fins are joined, deeply notched and unmottled. Sebastes mystinus snout is somewhat pointed, with a small mouth (maxilla does not reach the rear of the eye), vague dark bars across the forehead, and small eye diameter. The rear edge of the anal fin is straight or slightly indented. Sebastes mystinus has up to four pairs of weak head spines. The juvenile Sebastes mystinus can be recognized by its light blue body spotted with brick red.

Size:

<em>Sebastes mystinus</em> can grow to be 61 cm in length and weight 3.8 kg. Young of the year recruits are 3 to 3.6 cm.

Natural History:

General:

The maximum reported age for Sebastes mystinus is 44 years.

Movement and migration studies demonstrate that Sebastes mystinus is residential.

Sebastes mystinus, and most other bony fishes, adjust their buoyancy with a swim bladder which they inflate with gases, mostly oxygen. These fish also utilize their lateral line organ, an neural line along each side of the head and body that detects pressure changes. This organ permits the fish to swim in schools as well as to detect predators.

Predator(s):

At one time Sebastes mystinus was usually the most abundant rockfish in the catches of charter boat and skiff anglers off California. This is no longer true due to declines in the population caused by overfishing.

Adult Sebastes mystinus are subject to predation by other rockfish, lingcod, sharks, dolphins, seals, and sea lions. Young Sebastes mystinus are important food for fishes, particularly other rockfish, lingcod, cabezon, salmon, marine birds, porpoises, and other marine invertebrates.

Prey:

Sebastes mystinus feeds on small crustaceans, krill, jellyfishes, pelagic tunicates, gastropods, algae, squids, and small fishes in the midwater. Juveniles eat tiny crustacean, such as copepods and barnacle larvae.

Feeding Behavior:

Omnivore

Notes:

Sebastes mystinus is an aggressive feeder and often churns the surface waters when hunting as a school.

Since Sebastes mystinus has a small mouth and long gill rakesr, it can be an effective predator on plankton. Its long gut and unusually long and numberous absorptive villi in the stomach likely allow it to digest algae efficiently. The diet of Sebastes mystinus overlaps very little with that of other rockfish.

Seasonal Behavior

October - December

Reproduction:

Sebastes mystinus mates in October, but the embryos do not begin to develop until December when the eggs are fertilized by stored sperm.

January - January

Reproduction:

Embryos develop inside female Sebastes mystinus and hatch immediately when released into the water. The larval fish spend several weeks as part of the plankton community. It is believed that Sebastes mystinus spawn once a year.

February - March

Reproduction:

Larval are planktonic, and may be carried many kilometers by ocean currents.

April - May

Reproduction:

Young of the year Sebastes mystinus begin to appear in the kelp canopy and shallow rocky areas.

Issues

Monterey Bay National Marine Sanctuary:

Since until 2015 blue and deacon rockfish were considered the same and managed in the same way, there may be fishery-related issues due to the separation. For example, quotas in Oregon for blues might be reduced since that is in the northern part of the range, and similarly reduced for deacons in northern California near the southern limit of their range. Monterey has mostly blues but deacons do occur and either CDFW or NMFS may alter their fishing regulations to better manage the scarcer species (i.e. deacons).

References

• Alden, P., F. Heath, R. Keen, A. Leventer, and W. Zomlefer. 2002. National Audubon Society Field Guide to California. A.A. Knopf, New York, NY.
• Boschung, H.T., J.D. Williams, D.W. Gotshall, D.K. Caldwell, and M.C. Caldwell. 1998. National Audubon Society Field Guide to North American Fishes, Whales and Dolphins. A.A. Knoph, New York, NY. 848 p.
• Butler, J.L., M.S. Love, and T.E. Laidig. 2012. A guide to the rockfishes, thorny heads, and scorpionfishes of the northeast Pacific. University of California Press, Berkeley, CA. 185 p.
• Eschmeyer, W.N., and E.S. Herald. 1983. A Field Guide to Pacific Coast Fishes of North America. Houghton Mifflin Company, Boston, MA. 336 p.
• Frable et al. 2015. A new species of Sebastes (Scorpaeniformes: Sebastidae) from the northeastern Pacific, with a redescription of the blue rockfish, S. mystinus (Jordan and Gilbert, 1881). Fishery Bulletin 113(4):355-377.
• Froese, R. and D. Pauly (eds.). 2006 (Updated 01/02/06). FishBase. World Wide Web electronic publication. http://www.fishbase.org, Accessed [04/25/06].
• Gotshall, D. 2001. Pacific Coast Inshore Fishes. Sea Challengers, Monterey, CA. 117 p.
• Hallacher, L.E. and D.A. Roberts. 1985. Differential utilization of space and food by the inshore rockfishes (Scorpaenidae: Sebastes) of Carmel Bay, California. Environmental Biology of Fishes 12(2): 91-110.
• Humann, P. 1996. Coastal fish identification : California to Alaska. New World Publications, Jacksonville, FL. 205 p.
• Kramer, D.E., and V.M. O'Connell. 1988. Guide to Northeast Pacific Rockfishes Genera Sebastes and Sebastolobus. University of Alaska, Fairbanks, AK. 78 p.
• Lamb, A. and P. Edgell. 1986. Coastal Fishes of the Pacific Northwest. Harbor Publishing, Madeira Park, BC, Canada. 224 p.
• Langstroth, L. and L. Langstroth. 2000. A Living Bay: The Underwater World of Monterey Bay. University of California Press, Berkeley and Los Angeles, CA. 287 p.
• State of California. 2003. California Department of Fish and Game, Marine Region, Nearshore Finfish Profiles. World Wide Web electronic publication. http://www.dfg.ca.gov/mrd/rockfish/index.html, Accessed [09/30/06].

Related Information