Animal Diversity Web

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). (Green, et al., 2014; Love and West­phal, 1981)

• Biogeographic Regions
• pacific ocean
  • 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). (Green, et al., 2014; Love and West­phal, 1981)

• Habitat Regions
• saltwater or marine

• Aquatic Biomes
• pelagic
• reef
• coastal

• Range depth

  5 to 100 m

  16.40 to 328.08 ft

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). (Eigen­mann and Eigen­mann, 1890; Love, 1978; Love, et al., 2002)

• Other Physical Features
• 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). (Hal­dor­son and Love, 1991; Love and Caselle, 1998; 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). (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). (Love, 1978)

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

• Breeding season

  October to December, peaking in November

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). (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). (Green, et al., 2014; Hal­dor­son and Love, 1991)

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). (Green, et al., 2014; Lim­baugh, 1955)

• Key Behaviors
• natatorial
• diurnal
• motile
• sedentary
• 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). (Love and West­phal, 1981)

• Communication Channels
• visual
• acoustic
• chemical

• Perception Channels
• tactile
• 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). (Love and West­phal, 1981)

• Primary Diet
• carnivore
  • piscivore
  • molluscivore
• 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. (Love and West­phal, 1981)

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). (John­son, 2006; Lim­baugh, 1955; 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). (Love, et al., 1990; O'Far­rell and Bots­ford, 2006; Schroeder and Love, 2002)

• Positive Impacts
• 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). (Love and Caselle, 1998)

• IUCN Red List

  No special status

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

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.