Sebastes serranoides

Geographic Range

Olive rockfish are typically found in the Pacific Ocean off the coast of California from Del Norte County to Baja California, Mexico and is usually found around a depth of 5-100 m (Love and Westphal, 1981). These rockfish are commonly called “long-term residents”, indicating that migration is not common in this species despite changes in water conditions. (Green, Greenley and Starr, 2014).

• Biogeographic Regions
• pacific ocean pacific ocean
  • native native

Habitat

Juvenile olive rockfish are pelagic fish, occupying a depth less than 100 m. They live close to the shore in rock reefs and kelp forests (Green, Greenley, and Starr, 2014). After a few months, however, they are found at varying depths (Love and Westphal, 1981).

• Habitat Regions
• saltwater or marine saltwater or marine

• Aquatic Biomes
• pelagic pelagic
• reef reef
• coastal coastal

Physical Description

Sebastes serranoides is gray in color and darker dorsally. There may be visible white spots along the sides, and the fins may have a yellow tint with a dusky edge. Olive rockfish have large scales that get smaller towards the head. The head is compressed and has a long, pointed snout with a lower protruding jaw (Eigenmann and Eigenmann, 1890). The juveniles tend to be a lighter brown than the adults and have irregular spots above the lateral line. They may also have small black spots visible on the anal fins and a large black spot between dorsal spines 8 and 11. This large spot is typically absent in adult rockfish larger than 35 cm (Love, 1978). The males usually have larger eyes and longer pectoral fin. Females tend to grow larger than the males (Love, Yoklavich, and Thorsteinson, 2002).

• Other Physical Features
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Development

Members of the Sebastes genus are known to have internal fertilization and are ovoviviparous fishes. The eggs are carried and hatch inside of the ovaries of the female (Haldorson and Love, 1991; Love and Caselle, 1998). The larvae of S. serranoides are released from December through March, the majority of which are released in January (Love and Westphal, 1981). When the larvae are released, they stay in the upper layer of the water. After a month, the larvae become pelagic juveniles (Love and Caselle, 1998). After a period of about 3 to 6 months, these fish begin to settle in waters of various depths, particularly in rocky reefs and kelp habitats (Love and Westphal, 1981).

Reproduction

Not much is known about the mating behaviors of olive rockfish, but it is speculated that there are several mechanisms in place to prevent cross-breeding between closely related species of Sebastes that have the same mating season. The male copulatory organs of the olive rockfish are small making it difficult for other species to fertilize the females of S. serranoides . There may also be auditory, visual, and chemical mechanisms at work that prevent cross-breeding (Love and Westphal, 1981).

Not much is known about the reproductive general behaviors of the olive rockfish; however, the mating season of S. serranoides is believed to be from October to December, peaking in November (Love, 1978).

• Key Reproductive Features
• sexual sexual
• fertilization fertilization
  • internal internal
• ovoviviparous ovoviviparous

Not much is known about the amount of parental investment of the olive rockfish after birth; however, Sebastes serranoides is an ovoviviparous, taking care of the eggs until they are ready to be hatched (Haldorson and Love, 1991; Love and Caselle, 1998).

• Parental Investment
• pre-hatching/birth
  • provisioning
    • female

Lifespan/Longevity

Rockfish are known to be slow-growing (Haldorson and Love, 1991) with a life span of around 30-50 years (Green, Greenley, and Starr, 2014).

Behavior

Olive rockfish are known to be relatively stable and are likely to stay in one area despite changes in water conditions. They are also more active during the day than at night (Green, Greenley, and Starr, 2014). At around 1 to 4 inches, juveniles are typically found in schools, but as they grow larger, they tend to prefer solitude (Limbaugh, 1955).

• Key Behaviors
• natatorial natatorial
• diurnal diurnal
• motile motile
• sedentary sedentary
• solitary solitary

Home Range

Sebastes serranoides are typically found off the coast of California from Del Norte County to Baja California, Mexico.

Communication and Perception

Not much is known about communication of olive rockfish, but it is suspected that there are auditory, visual, and chemical mechanisms used by the fish in order to prevent cross-breeding between closely related species (Love and Westphal, 1981).

• Communication Channels
• visual visual
• acoustic acoustic
• chemical chemical

• Perception Channels
• tactile tactile
• chemical chemical

Food Habits

The food habits of the olive rockfish change as the fish gets older and depending on the season. Juvenile rockfish are dependent on plankton and small fishes found in midwaters as a source of food. During the upwelling period, the rockfish depends more on nekton, such as squid and young rockfish. The dependence on young rockfish, however, decreases in the fall and winter due to the juveniles becoming older and are unable to be easily caught. During these seasons, other prey are targeted, such as the northern anchovy. The diet of adult rockfish mainly consists of small fishes, such as blue rockfish, young olive rockfish, and pipefish, and of substrate-oriented prey, such as octopus and squid (Love & Westphal, 1981).

• Primary Diet
• carnivore carnivore
  • piscivore piscivore
  • molluscivore molluscivore
• planktivore planktivore

• Animal Foods
• fish
• mollusks
• aquatic crustaceans

Predation

During the upwelling period, juvenile olive rockfish, as well as other species of rockfish, are an important food source for adult rockfish and other fish species (Love and Westphal, 1981). Not much is known about what organisms prey on the adults of this species.

Ecosystem Roles

Juvenile rockfish are an important food source for other adult rockfish and other species of fish. The adults of this species feed on small fishes and on substrate-oriented prey, such as octopus and squid (Love and Westphal, 1981). Predation is important for the regulation of the population sizes of these food sources (Johnson, 2006). The olive rockfish were thought to be replacing the kelp bass in the areas around central and northern California (Limbaugh, 1955), but this is unlikely since the two fish species do not typically rely on the same food sources (Love and Westphal, 1981).

Economic Importance for Humans: Positive

Olive rockfish are important both as a sports fish and in the commercial fishing industry (Schroeder and Love, 2002; O’Farrell and Botsford, 2006; Love et al., 1990).

• Positive Impacts
• food food

Economic Importance for Humans: Negative

Not much is known about the olive rockfish's negative impacts on humans.

Conservation Status

The olive rockfish is not a threatened species; however, there is evidence that the population of rockfish found off the coast of southern California has declined. There was a sharp drop in the population during the 1970s, and the population has remained at a constant low level possibly due to environmental conditions and overfishing (Love and Caselle, 1998).

Additional Links

Encyclopedia of Life

Contributors

Thanh-Van Nguyen (author), Louisiana State University, Prosanta Chakrabarty (editor), Louisiana State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Eigenmann, C., R. Eigenmann. 1890. Description of a new species of Sebastodes . Proceedings of the California Academy of Sciences, 3: 36-38.

Green, K., A. Greenley, R. Starr. 2014. Movements of blue rockfish ( Sebastes mystinus ) off central California with comparisons to similar species. Plos One , 9: 1-11.

Haldorson, L., M. Love. 1991. Maturity and fecundity in the rockfishes, Sebastes spp., a review. Marine Fisheries Review , 53: 25-31.

Johnson, D. 2006. Predation, habitat complexity, and variation in density-dependent mortality of temperate reef fishes. Ecology , 87: 1179-1188.

Limbaugh, C. 1955. "Fish life in the kelp beds and the effects of kelp harvesting" (On-line pdf). Accessed November 01, 2015 at http://escholarship.org/uc/item/4w36x6mb .

Love, M., J. Caselle. 1998. Declines in nearshore rockfish recruitment and populations in the southern California Bight as measured by impingement rates in coastal electrical power generating stations. Fishery Bulletin , 96: 492-501.

Love, M., P. Morris, M. McCrae, R. Collins. 1990. Life history aspects of 19 rockfish species ( Scorpaenidae: Sebastes ) from the southern California Bight. NOAA Technical Report NMFS , 87: 1-38.

Love, M., W. Westphal. 1981. Growth, reproduction, and food habits of olive rockfish, Sebastes serraoides , off central California. Fishery Bulletin , 79: 533-545.

Love, M., M. Yoklavich, L. Thorsteinson. 2002. The rockfishes of the northeast Pacific . Berkeley, CA: University of California Press.

Love, M. 1978. "Aspects of the life history of the olive rockfish, Sebastes serranoides " (On-line pdf). Accessed October 06, 2015 at https://escholarship.org/uc/item/26j8768b .

O'Farrell, M., L. Botsford. 2006. Estimating the status of nearshore rochfkish ( Sebastes spp.) populations with length frequency data. Ecological Applications , 16: 977-986.

Schroeder, D., M. Love. 2002. Recreational fishing and marine fish populations in Califonia. California Cooperative Oceanic Fisheries Investigations Report , 43: 182-190.