Animal Diversity Web

Ge­o­graphic Range

Giant sea bass in­habit coastal wa­ters of Cal­i­for­nia, from Hum­boldt Bay to the tip of Baja Cal­i­for­nia, Mex­ico. ("Ma­rine Sport­fish Iden­ti­fi­ca­tion: Sea Bass", 2012; Sepul­veda and Aal­bers, 2009)

• Biogeographic Regions
• nearctic
  • native
• pacific ocean
  • native

Habi­tat

Ju­ve­nile giant sea bass are found at depths of 6 to 10 m, over mud flats and in coastal la­goons of south­ern Cal­i­for­nia and the Baja Cal­i­for­nia penin­sula. Older ju­ve­niles and adults are found in 10 to 40 m of water over sandy bot­toms, kelp beds and rocky reefs, as well as within deep ridges at depths of 70 to 80 m. Adult sea bass ven­ture off­shore of these coastal areas at var­i­ous times in the year to prey on groups of spawn­ing squid. (Sepul­veda and Aal­bers, 2009)

• Habitat Regions
• temperate
• saltwater or marine

• Aquatic Biomes
• benthic
• coastal

• Range depth

  6 to 80 m

  19.69 to 262.47 ft

• Average depth

  40 m

  131.23 ft

Phys­i­cal De­scrip­tion

Ju­ve­nile giant sea bass are a bril­liant shade of or­ange, with dis­tinc­tive large black spots. As a fish ma­tures, its spots dem­i­nish and its col­or­ful ex­te­rior grad­u­ally dark­ens and ac­quires a bronzy pur­ple hue. At full ma­tu­rity, it be­gins to de­velop a white un­der­side while the rest of its body turns black or even gray. Fea­tures char­ac­ter­is­tic of giant sea bass are dor­sal spines that fit into grooves in the back and a large mouth spe­cial­ized for am­bush pre­da­tion. Per­haps the most well-known fea­ture of this species is its large size, with in­di­vid­u­als his­tor­i­cally ex­ceed­ing 2 me­ters in length. ("Ma­rine Sport­fish Iden­ti­fi­ca­tion: Sea Bass", 2012; Sepul­veda and Aal­bers, 2009)

• Other Physical Features
• ectothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike

• Range mass

  255.6 (high) kg

  563.00 (high) lb

• Range length

  2.5 (high) m

  8.20 (high) ft

De­vel­op­ment

There is lit­tle spe­cific in­for­ma­tion on the de­vel­op­ment of this species. Like in other broad­cast spawn­ing ma­rine teleosts, fer­til­ized eggs de­velop into plank­tonic, le­chithotropic lar­vae that drift with coastal cur­rents while de­vel­op­ing into fully de­vel­oped ju­ve­niles. (Bond, 1996)

• Development - Life Cycle
• indeterminate growth

Re­pro­duc­tion

Spawn­ing be­hav­ior of giant sea bass has rarely been ob­served in the field. One study doc­u­mented groups of 2 to 20 fish spawn­ing in one par­tic­u­lar area. As is the case with other broad­cast spawn­ing species, pair bonds are not formed, and in­di­vid­u­als may spawn mul­ti­ple times with sev­eral dif­fer­ent mates. (Sepul­veda and Aal­bers, 2009)

• Mating System
• polygynandrous (promiscuous)

Male giant sea bass reach sex­ual ma­tu­rity at about 18 kg, while fe­males ma­ture at sizes of 23 to 27 kg. These sizes cor­re­spond to an age of 11 to 13 years for ei­ther gen­der. Dur­ing a three mouth spawn­ing pe­riod from July to Sep­tem­ber, fe­males may pro­duce up to 60,000,000 eggs. After fer­til­iza­tion, the eggs ab­sorb water and swell up, mea­sur­ing up to 1.6 mm in di­am­e­ter (much larger than the eggs of other bass species). Eggs are pos­i­tively buoy­ant and float to the sur­face. After hatch­ing, lar­vae drift and feed on plank­ton for about a month until they sink and start their ju­ve­nile phase. (Sepul­veda and Aal­bers, 2009)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • external
• broadcast (group) spawning
• oviparous

• Breeding interval

  Giant sea bass spawn annually, potentially engaging in multiple individual spawning events during a single spawning season.

• Breeding season

  Spawning occurs once a year between July to September.

• Range number of offspring

  60,000,000 (high)

• Range time to hatching

  24 to 36 hours

• Range age at sexual or reproductive maturity (female)

  11 to 13 years

• Range age at sexual or reproductive maturity (male)

  11 to 13 years

As is the case with the ma­jor­ity of species that broad­cast spawn, there is no parental in­vest­ment be­yond the en­ergy re­quired to pro­duce ga­metes. (Sepul­veda and Aal­bers, 2009)

• Parental Investment
• no parental involvement

Lifes­pan/Longevity

The old­est sci­en­tif­i­cally aged fish was es­ti­mated to be 75 years old, weigh­ing 197 kilo­grams. It is be­lieved that giant sea bass may po­ten­tially live for over a cen­tury. (Bush­ing, 2009)

• Range lifespan
  Status: wild

  75 (high) years

• Typical lifespan
  Status: wild

  100 (high) years

Be­hav­ior

Giant sea bass move among kelp beds and rocky reefs to wait for and am­bush their prey. Their large mouth opens quickly, cre­at­ing a vac­uum that sucks the prey into the mouth. Due to its rar­ity in the wild, other be­hav­iors have not been ob­served in this species, but it is as­sumed that giant sea bass might dis­play sim­i­lar be­hav­iors to other species of a sim­i­lar size, such as groupers. (Sepul­veda and Aal­bers, 2009)

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

Home Range

In­di­vid­u­als have been re­peat­edly ob­served in the same lo­ca­tions, in­di­cat­ing that these fish re­side within par­tic­u­lar areas. How­ever, there are no pub­lished es­ti­mates of the size of these home ranges. (Sepul­veda and Aal­bers, 2009)

Com­mu­ni­ca­tion and Per­cep­tion

This species has the abil­ity to rapidly and dra­mat­i­cally change color, pro­duc­ing black spots and white mot­tling over the body. It is be­lieved that these color changes serve as stress sig­nals and a means of com­mu­ni­ca­tion be­tween con­specifics. In ad­di­tion to the use of vi­sual cues, giant sea bass are able to per­ceive their en­vi­ron­ment through the use of their lat­eral line sys­tem, which de­tects pres­sure changed and move­ment in sur­round­ing wa­ters. They can also de­tect dis­solved chem­i­cal sub­stances via their nares, which are anal­o­gous to nos­trils in ter­res­trial an­i­mals. (Sepul­veda and Aal­bers, 2009)

• Communication Channels
• visual

• Perception Channels
• visual
• tactile
• acoustic
• vibrations
• chemical

Food Habits

Giant sea bass mainly con­sume ben­thic in­ver­te­brates in­clud­ing rock crab (Can­cer an­ten­nar­ius) and Cal­i­for­nia spiny lob­ster (Pan­ulirus in­ter­rup­tus), and will also prey on other fishes, such as round stingrays (Uro­batis hal­leri), ocean white­fish (Caulo­latilus prin­ceps), Cal­i­for­nia bar­racuda (Sphyraena ar­gen­tea), kelp bass (Par­al­abrax clathra­tus), and barred sand bass (Par­al­abrax neb­u­lifer). They are sit-and-wait am­bush preda­tors, that cap­ture their prey by rapidly open­ing their mouth, cre­at­ing a vac­uum that sucks their prey into their throats. (Schultze, 1983; Sepul­veda and Aal­bers, 2009)

• Primary Diet
• carnivore
  • piscivore
  • eats non-insect arthropods
  • molluscivore

• Animal Foods
• fish
• mollusks
• aquatic crustaceans
• echinoderms

Pre­da­tion

Giant sea bass are most likely to be preyed upon while they are in lar­val or ju­ve­nile stages, by a wide va­ri­ety of ma­rine mam­mals and fish. Due to their large size, only large sharks and hu­mans have the abil­ity to prey on adults. (Sepul­veda and Aal­bers, 2009)

• Known Predators

  • great white sharks (Carcharodon carcharias)
  • humans (Homo sapiens)

Ecosys­tem Roles

Giant sea bass are top-level car­ni­vores that prey on many kelp for­est species of in­ver­te­brates and fish. This species is also a host for en­dopar­a­sitic mono­ge­nean flukes and ec­topar­a­sitic isopods, which at­tach them­selves to the gill rak­ers. Señori­tas are a species of cleaner fish that share a mu­tu­al­is­tic sym­bio­sis with giant sea bass, re­mov­ing these ex­ter­nal crus­tacean par­a­sites from the gills, skin, and in­side of the mouth. ("Ma­rine Sport­fish Iden­ti­fi­ca­tion: Sea Bass", 2012; Eris­man and Aburto, 2012; Oliver, 1984; Sepul­veda and Aal­bers, 2009)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Giant sea bass were one of the most eco­nom­i­cally im­por­tant species of fish in the Gulf of Cal­i­for­nia and were fished heav­ily in the 1930’s and 40’s for their value as food. As a pro­tected species, their cur­rent value lies in eco­tourism, at­tract­ing divers from around the world to coastal ma­rine sanc­tu­ar­ies in Cal­i­for­nia to catch a glimpse of these un­der­sea gi­ants. (Eris­man and Aburto, 2012; Sepul­veda and Aal­bers, 2009)

• Positive Impacts
• ecotourism
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known ad­verse ef­fects of giant sea bass on hu­mans.

Con­ser­va­tion Sta­tus

Giant sea bass have been pro­tected in Cal­i­for­nia since 1982, when the Cal­i­for­nia State Leg­is­la­ture rec­og­nized the great de­cline in pop­u­la­tions and banned recre­ational and com­mer­cial fish­ing for this species. How­ever, the species can still be fished in Mex­ico. In 1990, Propo­si­tion 132 passed in Cal­i­for­nia, ban­ning the use of gill nets within coastal wa­ters as a pub­lic ini­tia­tive to pre­vent fur­ther pop­u­la­tion de­clines of giant sea bass. (Cor­nish, 2004; Sepul­veda and Aal­bers, 2009)

• IUCN Red List

  Critically Endangered

• US Federal List

  Endangered

• CITES

  No special status

• State of Michigan List

  No special status

Con­trib­u­tors

Zack Helke (au­thor), San Diego Mesa Col­lege, An­tone Lahr (au­thor), San Diego Mesa Col­lege, Paul De­twiler (ed­i­tor), San Diego Mesa Col­lege, Je­remy Wright (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

2012. "Ma­rine Sport­fish Iden­ti­fi­ca­tion: Sea Bass" (On-line). Cal­i­for­nia De­part­ment of Fish and Game. Ac­cessed March 24, 2012 at http://​www.​dfg.​ca.​gov/​marine/​mspcont9.​asp#​giant.

Bond, C. 1996. Bi­ol­ogy of Fishes, 2nd Edi­tion. Pa­cific Grove, CA: Brooks/Cole Pub­lish­ing Com­pany.

Bush­ing, B. 2009. "Black Sea Bass, Stere­olep­sis gigas" (On-line). Un­der­wa­ter Pho­tog­ra­phy Guide. Ac­cessed March 21, 2012 at http://​www.​uwphotographyguide.​com/​black-sea-bass.

Cor­nish, A. 2004. "IUCN Red List of Threat­ened Species" (On-line). Stere­olepis gigas. Ac­cessed March 21, 2012 at http://​www.​iucnredlist.​org/​.

Eris­man, B., O. Aburto. 2012. "Scripps In­sti­tu­tion of Oceanog­ra­phy" (On-line). Reef Fish Con­ser­va­tion in East­ern Pa­cific. Ac­cessed March 21, 2012 at http://​cmbc.​ucsd.​edu/​Research/​Gulf_​of_​California/​Reef_​Fish_​Conservation/​.

Hen­drickx, M., M. Es­pinosa-Pérez. 2001. Check­list of isopods (Crus­tacea: Per­acarida: Isopoda) from the East­ern Trop­i­cal Pa­cific. Bel­gian Jour­nal of Zo­ol­ogy, 131 (1): 43-55. Ac­cessed May 03, 2012 at http://​unam.​academia.​edu/​MichelHendrickx/​Papers/​515055/​Checklist_​of_​isopods_​Crustacea_​Peracarida_​Isopoda_​from_​the_​Eastern_​Tropical_​Pacific.

Oliver, G. 1984. [De­scrip­tion of 2 new species of the genus Cy­clo­plectanum Oliver, 1968 (Mono­ge­nea, Monopistho­cotylea, Diplectanidae)]. An­nales de Par­a­sitolo­gie hu­maine et com­parée, 59/1: 31-39.

Schultze, D. 1983. Cal­i­for­nia bar­racuda life his­tory, fish­eries, and man­age­ment. Cal­COFI Re­port, XXIV: 88-96. Ac­cessed May 03, 2012 at http://​www.​calcofi.​org/​publications/​calcofireports/​v24/​Vol_​24_​Schultze.​pdf.

Sepul­veda, C., S. Aal­bers. 2009. "The Giant Sea Bass: Sta­tus of Bi­o­log­i­cal Knowl­edge" (On-line). PIER. Ac­cessed March 21, 2012 at http://​www.​pier.​org/​CA_​coastal_​gs_​bass_​biological.​shtml.