California sheephead
The California sheephead is a species of wrasse native to the eastern Pacific Ocean. Its range is from Monterey Bay, California, to the Gulf of California, Mexico. It can live for over 50 years and can reach a size of up to and a weight of. It is carnivorous, living in rocky reef and kelp bed habitats, feeding primarily on sea urchins, molluscs, and crustaceans.
All California sheephead are hatched 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. Since fisheries tend to remove the largest fish, they end up removing the males. This skews the male-to-female ratio and affects the fishes' lifecycle, which can negatively affect populations.
Taxonomy
The species is most closely related to the Asian and goldspot sheephead wrasse. The three species were previously considered to form their own genus Semicossyphus, but are now lumped into Bodianus, after molecular phylogenetics showed that Semicossyphus was nested deep within Bodianus.Etymology
Bodianus is New Latin. Pulcher is the Latin word for beautiful. In French, the fish is called the labre Californien, and in Spanish it is called the vieja de California.Description
Male and female California sheepheads 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 silvery or 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. After powerful jaws and sharp teeth crush the prey, modified throat bones 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. The species can live for over 50 years.Biology
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. The two sexes have extremely different appearances, so this transition is among the most dramatic among the wrasses. Because only large individuals are male, setting minimum catch sizes has made populations mostly female, with a negative effect on population sizes.
Distribution and habitat
Home ranges in California sheephead vary greatly, and this variability can be attributed to differences in habitat shape and to natural habitat boundaries. It is 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. They may select rocky areas with kelp most often due to the increased habitat complexity, which likely offers additional feeding opportunities and potential refuge from large predators. Sheephead generally are considered mainly a rocky-reef and kelp-bed associated species, but they occasionally frequent sand habitats in foraging forays.Ecology
The California sheephead is a monandric protogynous hermaphrodite and is a commercially and recreationally valuable labrid. It is 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.Feeding
The California sheephead is a carnivorous, epibenthic reef fish, foraging mostly in the daytime in sand-rock reef habitats. Its feeding territories are very productive and allow individuals to occupy small, permanent, economically defendable home ranges. As a large temperate wrasse, it is a predator of sea urchins and other benthic invertebrates and play a critical role in also regulating prey populations in kelp forests. Since it feeds heavily on urchins, it is consequently an important species for indirectly regulating kelp growth in southern California's coastal waters. However, it exhibits flexibility in prey selection if its main food source is not readily available at a particular time. Populations with diets dominated by crabs and sea urchins, however, reach larger sizes and mature and change sex at larger sizes than populations that consume higher proportions of bivalves, barnacles, and bryozoans. Since they forage in the daytime and are considered a diurnal species, they may rely on anatomical characteristics which allow them to feed in exposed locations in broad daylight while overcoming the defenses evolved by their prey. They forage both in groups and alone, and larger fish tend to shift towards more heavily armored prey.Predation
As a reef fish, signals about the sheephead's predation risk often comes from the presence of damage-released chemical cues produced by injured prey animals. These clues are only released when the skin is ruptured, and act as a reliable indicator of the presence of an actively foraging predator. Chemical cues may be released not only with injury, but also when pathogens or parasites penetrate the skin; therefore, the reliability of the chemical cues as indicators of predation risk is decreased. When a sheephead is captured by a predator, and damage-released chemical cues are discharged, the information is available for both conspecifics and heterospecifics to use.Migration and territoriality
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. However, males also show wider ambits than females, and the size of their ambits changes seasonally. During spawning season, males show a daily increase in their ambits during a period of potential spawning, and also make daily journeys offshore into deeper water. Females do not expand their ambits significantly during this same period. Each of the movements offshore by males is followed by a return to nearshore habitat prior to twilight, suggesting the occupation of a spawning territory at that time. 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.