California sheephead (Semicossyphus pulcher) are found in the Eastern Pacific Ocean along the California coast, from Monterey Bay to the Gulf of California (Cabo San Lucas). They are sometimes seen in the Gulf of California, Mexico, but are most abundant south of Point Conception, California. (California Natural Resources Department of Fish and Game, 2011; Cornish and Dormeier, 2010)
California sheephead inhabit rocky shoreline reefs, in and around kelp beds between 6 and 30 m in depth. ("California sheephead", 2011)
Juvenile California sheephead are bright reddish-orange with large blue spots on the dorsal, pelvic, and anal fins. They also have a white line running horizontally from the eye to the caudal fin. Male and female sheephead are sexually dimorphic. Males are black with and orange midsection and white chin. They have red eyes and a prominent, bulbous forehead. Females lack marked coloration but instead, are dull pink with white undersides. They are also smaller than males, lack the prominent forehead bulb present in males, are less robust overall. California sheephead have protruding teeth used to prey upon hard-shelled animals. Although average size is unknown, they can grow to be 16 kg in mass and 1 m long. ("California sheephead", 2011)
During spawning season, which lasts from August to October in coastal California, female California sheephead produce between 36,000 to 296,000 eggs. Eggs are fertilized while suspended in the water column and hatch into planktonic larvae. Females may spawn over 80 times annually. All larvae begin life as females, and those that survive to adulthood may change sex, developing into males if the dominant male leading the harem dies or leaves. Sex changeover in California sheephead typically occurs between 5 and 13 years of age, but can vary between locations. In areas of high food abundance, females change sex at a later age. (Cornish and Dormeier, 2010; "California sheephead", 2011)
California sheephead are polygamous, with dominant males maintaining a harem of females that is defended from other males. (Adreani, et al., 2004)
California sheephead follow a consistent mating routine, which begins about an hour before sunset, as a group of females gather below the kelp canopy. Meanwhile, the largest and more dominant males define their territory by forcing smaller males outside from their courting zone, which is approximately 25 m in diameter. The male then selects a female and the mating process begins. The male circles above the female, keeping his pelvic fins down, and places his chin on the female’s head. After they circle and display several jerking motions, they swim to within 3 to 4 meters of the surface and spawn. Males repeat this process with each female, until all females in his territory have been mated or until sunset. Most individuals are sexually mature by 4 year of age. (Adreani, et al., 2004)
California sheephead are broadcast spawners. After eggs and sperm are released into the water column, fertilized planktonic eggs drift away with the current. Thus, parental care is nonexistent in this species.
Although the average lifespan of California sheephead is unknown, they can live up to 53 years in the wild. However, due to commercial and recreational fishing, few animals attain this age. Aside from fishing pressure, natural causes of mortality are unknown. (Cornish and Dormeier, 2010; "California sheephead", 2011)
California sheephead forage during the day with harem members and the dominant male. At night, they station themeselves beneath rock overhangs or within crevices, and like several other species of wrasse, they encase themselves in a protective cocoon of mucus while quiescent. Males display aggressive tendencies, including territorial behaviors during mating. Research suggests that catching and releasing these animals causes stress and may alter their behavior. In aquarium settings, the secondary stress response of increased insulin and cortisol has a significant affect on the behavior of California sheephead, even after the stressful event has passed. Further evidence suggests that levels of cortisol may be reduced through increased swimming. Thus, providing captive sheephead with adequate room in aquaria may reduce the frequency of stress-induced behaviors. (Adreani, et al., 2004; Lowe and Kelley, 2004; Lowery, et al., 2010; "California sheephead", 2011)
Home range size in California sheephead, which ranges between 938 and 82,070 m^2, appears to be contingent on topography of the local environment. (Topping, et al., 2005)
California sheephead communicate primarily through visual cues and displays. Males are black and orange, as opposed to the solid orange of females. Dominance hierarchies are formed in relation to size and age, and the presence of a male inhibits the sex change process in high-ranking females. Although many kelp forest fish are known to communicate with sound, there is no information on whether auditory communication is utilized by California sheephead. Like most bony fishes, they use the lateral line system to sense movement in the surrounding environment. ("California sheephead", 2011)
California sheephead consumes benthic invertebrates including the purple sea urchins, Pacific rock crabs, acorn barnacles, mussels, clams, and bryozoans. They also eat snails, squids, common sand dollars, eccentric sand dollars, and sea cucumbers. Their large canine-like teeth are used to pry sessile invertebrates from rocks. A special pharyngeal plate in the throat crushes calcareous skeletal materials into small pieces so the prey's tissues can be separated and digested. ("California sheephead", 2011)
In addition to being a popular game fish for anglers and spearfishers, California sheephead are commercially fished as well. Aside from human predation, California sheephead fall prey to various species of pinniped, including harbor seals and California sea lions and sea birds, such as double-crested cormorants (California Department of Fish and Game, 2011)
California sheephead are carnivorous secondary and tertiary consumers, preying on various invertebrate species of kelp forest organisms. Their presence in kelp forests reduces the populations of California spiny lobsters and benthic grazing organisms such as purple sea urchins, red sea urchins, and gastropod mollusks. Senorita fish are known to clean parasites from the gills and skin of California sheephead, which are a known host of digenean flatworms. (McClanahan and George, 2008; Nichols, 2009; Norse and Crowder, 2005)
California sheephead are fished by anglers and spearfishers for food, and are caught live for the aquarium trade. The recreational and commercial catch of sheephead in 1999 was estimated at over 132,000 fish. In 2009, fishing vessels generated $333,801 in revenue from sheephead, much of that due to the lucrative live fish industry in Asian markets. California sheephead are economically valuable as keystone predators on purple sea urchins and red sea urchins, keeping them from overgrazing kelp forests. Thus, where they are present, sheephead contribute to the growth and biodiversity of kelp forests, and the corresponding increase in populations of other commercially-valuable fish species that are dependent on kelp habitat, such as kelp bass and white seabass. (California Department of Fish and Game, 2011; Cornish and Dormeier, 2010; Hackett, et al., 2009; McClanahan and George, 2008)
There are no known adverse effects of California sheephead on humans.
California sheephead are classified as "vulnerable" on the IUCN's Red List of Threatened Species. In 2001, the California Department of Fish and Game (CDFG) developed regulations to help manage this species. In 2004, the CDFG reported the status of the fishery and identified the following needs: 1) increased need for biological data to contribute to the development of more appropriate growth rates and models, 2) behavioral studies of sex changing females to understand whether reducing fishery pressure or closing fishing seasons altogether would be more effective, and 3) more studies on exploitation rates of this species in the Gulf of California. The single major threat to their persistence is over-fishing. In 2001, size limits helped reduce commercial harvest, and bag limits helped reduce recreational harvest. Since 2002, further regulations have been placed on the California sheephead fishery, which essentially represents a seasonal closure to commercial fishing. (California Department of Fish and Game, 2004)
Tan Doan (author), San Diego Mesa College, Lindzey Graves (author), San Diego Mesa College, Sierra Graves (author), San Diego Mesa College, Itzel Perez (author), San Diego Mesa College, Michelle Pineda (author), San Diego Mesa College, Paul Detwiler (editor), San Diego Mesa College, John Berini (editor), Special Projects.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
uses sound to communicate
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
fertilization takes place outside the female's body
union of egg and spermatozoan
A substance that provides both nutrients and energy to a living thing.
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter).
eats mollusks, members of Phylum Mollusca
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
having more than one female as a mate at one time
condition of hermaphroditic animals (and plants) in which the female organs and their products appear before the male organs and their products
mainly lives in oceans, seas, or other bodies of salt water.
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
uses sight to communicate
Monterey Bay Aquarium Foundation. 2011. "California sheephead" (On-line). Monterey Bay Aquarium. Accessed March 26, 2011 at http://www.montereybayaquarium.org/animals/AnimalDetails.aspx?id=780192.
Adreani, M., B. Erisman. R. 2004. Courtship and spawning behavior in the California sheephead, Semicossyphus pulcher (Pisces: Labridae). Environmental Biology of Fishes, 71: 13-19. Accessed March 20, 2011 at http://gulfprogram.ucsd.edu/sites/gulfprogramdev.ucsd.edu/files/Observationscourtship_sheephead.pdf.
California Department of Fish and Game, 2011. "California Department of Fish & Game, Marine Region, Marine Sportfish Identification: Other Fishes" (On-line). Accessed April 25, 2011 at http://www.dfg.ca.gov/marine/mspcont7.asp.
California Department of Fish and Game, 2004. "Status of the California Sheephead Stock for 2004" (On-line). Accessed May 19, 2011 at http://www.dfg.ca.gov/marine/sheephead2004/pdfs/summary.pdf.
California Natural Resources Department of Fish and Game, 2011. "2011 Commercial Fish Business License" (On-line). California Department of Fish and Game. Accessed April 25, 2011 at http://www.dfg.ca.gov/licensing/pdffiles/Guide2011.pdf.
Cornish, A., M. Dormeier. 2010. "Semicossyphus pulcher" (On-line). The IUCN Red List of Threatened Species. Accessed May 19, 2011 at http://www.iucnredlist.org/apps/redlist/details/61340/0.
Department of Fish and Game Marine Region, 2010. "2010 California Legislative Fisheries Forum" (On-line). Accessed April 25, 2011 at http://www.dfg.ca.gov/marine/pdfs/forum10.pdf.
Hackett, S., D. Hansen, D. King, E. Price. 2009. "The Economic Structure of California’s Commercial Fisheries" (On-line). California Department of Fish and Game. Accessed April 25, 2011 at http://www.dfg.ca.gov/marine/eccf/eccf_report.pdf.
Lowe, C., K. Kelley. 2004. "Fisheries Research and Development: Catch and Release of California Sheephead: Physiological and Behavioral Stress Effects" (On-line pdf). Sea Grant. Accessed March 27, 2011 at http://www.csgc.ucsd.edu/BOOKSTORE/Resources/PP2004/RF192.pdf.
Lowery, M., K. Kelley, M. Drawbridge. 2010. "Exercising Juvenile Marine Finfish to Enhance Growth and Lower Stress" (On-line pdf). Sea Grant. Accessed March 27, 2011 at http://www.csgc.ucsd.edu/BOOKSTORE/Resources/PP2010/RA-126-Lowery.pdf.
McClanahan, T., B. George. 2008. Food Webs and the Dynamics of Marine Reefs. United States: Oxford University Press.
Nichols, K. 2009. "The effects of predators and habitat on sea urchin density and behavior in Southern California kelp forests" (On-line). Accessed March 28, 2011 at http://escholarship.org/uc/item/3zv9w2w2.
Norse, E., L. Crowder. 2005. Marine Conservation Biology: The Science of Maintaining the Sea's Biodiversity. Washington: Island Press.
Topping, D., C. Lowe, J. Caselle. 2005. Home range and habitat utilization of adult California sheephead, Semicossyphus pulcher (Labridae), in a temperate no-take marine reserve. Marine Biology, 147: 301-311.