California sheephead are monandric protogynous hermaphrodites and are commercially and recreationally valuable labrids. They are a prominent species occupying the southern California rocky reef and kelp bed fish assemblage. Both the ecology and life history patterns of California sheephead have been shown to vary with local environmental conditions.
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Sheep crabs are preyed upon by sea otters, cabezon, California sheephead, octopus, sharks, bay rays, California sea lions, and larger sheep crabs.
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When supplied with a large amount of food, the California sheephead can live for up to 21 years. If food is scarce, they can live up to 9 years.
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All California sheephead are born female and morph into their male form at various stages in their lifecycle, determined by environmental conditions and pressures. Because of this, they are considered to be protogynous hermaphrodites which have planktonic larvae. Their coral and kelp-heavy habitat provides protection from predators, which is important as this species is diurnal, foraging during the day and seeking shelter at night. The California sheephead is considered vulnerable due to high fishing rates off of the coast of southern California.
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The behavior of California sheephead is shaped by the daily cycle of light, twilight, and dark. Diurnal fishes, like the sheephead, make a round trip between their refuges and foraging areas twice a day, and additional daily trips may be made by breeding fishes to spawning sites. This elaborate diel timing of movements is driven by the need to forage or mate while minimizing predation. Patterns in the movement of California sheephead are mediated by fish sex and size; for example, large males will exhibit higher site fidelity than females.
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California sheephead populations vary spacially in reproductive potential and reproductive capacity, and these differences are correlated with the natural sea surface temperature gradient. Fish in cooler waters may require less energy for growth and may be able to convert more energy into reproduction than fish at warmer sites. Population densities and sex ratios of hermaphroditic fishes are also intimately linked to ecological factors and human activities. Spatial and temporal changes in fishing pressure, coupled with environmental changes across populations over time, tend to affect the reproductive potential of each population of California sheephead.
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Most labrids are protogynous hermaphrodites within a haremic mating system. A good example of this reproductive behavior is seen in the California sheephead. Hermaphroditism allows for complex mating systems. Labroids exhibit three different mating systems: polygynous, lek-like, and promiscuous .
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The sheepshead porgy (Calamus penna) is a species of fish of the porgy family, Sparidae, only found in the Atlantic Ocean. It is only distantly related to the California sheephead of the Pacific Ocean. Sheepshead Bay in Brooklyn is named after this fish.
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Spatially separate populations of California sheephead vary in their sex ratios (number of females to number of males), in size of individuals at sex change, and in the sex ratio threshold. Sheephead are also haremic spawners, meaning each male defends a group of females with which he breeds.
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After powerful jaws and sharp teeth crush the prey, modified throat bones (a throat plate) grind the shells into small pieces. California sheephead can reach a size of and a weight of . All sheepheads are born as females and eventually change to males at roughly . The age of the transition depends on environmental factors such as food supply.
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The California sheephead lives in kelp forests and rocky reefs, where it feeds on sea urchins, molluscs, lobsters, and crabs. Fertilized eggs are released into the water column and hatch, resulting in planktonic larva. Like many wrasse species, sheephead are protogynous. All are born female, and the largest individuals become male due to hormonal changes triggered by social cues.
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Deposit feeders, such as polychaetes, populate softer bottoms. Fish, such as dragonets, as well as sea stars, snails, cephalopods, and crustaceans are important predators and scavengers. Benthic organisms, such as sea stars, oysters, clams, sea cucumbers, brittle stars and sea anemones, play an important role as a food source for fish, such as the California sheephead, and humans.
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The fisheries grew rapidly, with sheephead becoming a large share of the catches. Because restaurant aquariums are small, commercial fisheries seek small, juvenile sheephead, usually females before they have reproduced. 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.
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Predators of this species other than mankind are sea otters (such as the southern sea otter, Enhydra lutris), fish (such as the California sheephead, Semicossyphus pulcher) and invertebrates, including crustaceans such as the striped shore crab, Pachygrapsus crassipes, and spiny lobsters. Competition for space with other species (such as the sea urchins Strongylocentrotus purpuratus and Strongylocentrotus franciscanus) is also frequent.
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California sheephead, Channel Islands National Marine Sanctuary Male and female California sheepsheads have different color patterns and body shapes. Males are larger, with black tail and head sections, wide, reddish orange midriffs, red eyes, and fleshy forehead bumps. Female sheephead are dull pink with white undersides. Both sexes have white chins and large, protruding canine teeth that can pry hard-shelled animals from rocks or inflict nasty puncture wounds on skin divers.
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Pagurus samuelis and live Tegula funebralis feeding on a dead gumboot chitonPagurus samuelis prefers to use the discarded shell of the black turban snail, Tegula funebralis. They are chiefly nocturnal scavengers that feed on algae, especially the giant kelp Macrocystis pyrifera, and detritus. In a laboratory setting, P. samuelis can survive on a diet of Pelvetia canaliculata. Predators of P. samuelis include fishes such as the pile perch (Rhacochilus vacca), California sheephead (Semicossyphus pulcher) and the spotted kelpfish, Gibbonsia elegans.
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California sheephead are carnivorous, epibenthic reef fish, foraging mostly in the daytime in sand-rock reef habitats. Their feeding territories are very productive and allow individuals to occupy small, permanent, economically defendable home ranges. As a large temperate wrasse, they are predators of sea urchins and other benthic invertebrates and play a critical role in also regulating prey populations in kelp forests. Since they feed heavily on urchins, they are consequently an important species for indirectly regulating kelp growth in southern California's coastal waters.
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Home ranges in California sheephead vary greatly, and this variability can be attributed to differences in habitat shape (embayment versus contiguous coastline) and to natural habitat boundaries (deep, sandy expanses). They are found in rocky- reef areas 54% of the time, and within those areas, a greater percentage of daytime is found in high relief areas. Although their home ranges are thought of as particularly well defined, the size and fidelity may vary ontogenetically and seasonally and with habitat availability. Sheephead home ranges are relatively small, and the fish have a very high site attachment.
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In Southern California, kelp forests persist without sea otters and the control of herbivorous urchins is instead mediated by a suite of predators including lobsters and large fishes, such as the California sheephead. The effect of removing one predatory species in this system differs from Alaska because redundancy exists in the trophic levels and other predatory species can continue to regulate urchins. However, the removal of multiple predators can effectively release urchins from predator pressure and allow the system to follow trajectories towards kelp forest degradation.Pearse, J.S. and A.H. Hines. 1987.
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The California sheephead is considered a vulnerable species because of its high fishing rates off of the coast of Southern California. Usually most of the fish caught are the largest males, causing a shortage in males in the population and the subsequent morphogenesis of the largest females to males. This, in turn, creates a deficiency in the number of eggs produced and weakens the population in a particular fishing area. Male numbers seem typically low which also could result in sperm limitation for the species, with further male reduction, resulting in reduced reproductive output: males are readily targeted in the recreational spear fishery.
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Mainly juveniles are included in important commercial trap fishery, with juveniles and smaller adults dominating the hook and line and recreational fishery. 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.
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At twilight, continuing to about 10 to 15 minutes after sunset, the degree of activity above the reef rapidly decreases and sheephead seek shelter for the night; this 'quiet' period is a time of major activity for larger reef predators. Male and female California sheephead have overlapping home ranges; although they are not usually considered a territorial species, male sheephead can exhibit territorial behavior. Male sheephead are increasingly territorial throughout the day during periods of spawning activity. Since spawning activity occurs around sunset, it may be that they only have differences in space use for short periods on various days during the spawning season, thus male territoriality only occurs in this same timespan.
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California sheephead can transition from a reproductively functional female to a functional male during the course of a lifespan in response to social factors. Protogynous sex change typically follows the size-advantage model, where gonadal transformation occurs once the reproductive potential of an individual would be greater as a male than as a female. The transitional phase takes between two weeks and several months, and steroid hormone concentrations are thought to be related to sex change due to the total degradation of the ovaries and the appearance of testes. The exact timing of the sexual morphogenesis is suppressed by aggressive interactions with dominant males and triggered by the removal of alpha males.
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Fresh fish and shellfish in Southern California tends to be expensive in restaurants, but every year since the end of WWII, the Pismo clam festival has taken place where the local population takes a large species of clam and bakes, stuffs, and roasts it as it is a regional delicacy. Fishing for pacific species of octopus and the Humboldt squid are common, and both are a feature of East Asian and other L.A. fish markets. Lingcod is a coveted regional fish that is often caught in the autumn off the coast of San Diego and in the Channel Islands and often served baked. California sheephead are often grilled and are much sought after by spear fishermen and the immigrant Chinese population, in which case it is basket steamed.
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