California Sheephead

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 (a throat plate) grind the shells into small pieces. California sheephead can reach a size of 91 cm (3 ft) and a weight of 16 kg (35 lb). All sheepheads are born as females and eventually change to males at roughly 45 cm (1.5 ft). The age of the transition depends on environmental factors such as food supply. The species can live for over 50 years.

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). 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.

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.

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.

California sheephead populations vary in their 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. 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.

The fishery for this species, which began in at least the late 1800s (for salted fish), peaked in 1928 with landings of 370,000 lb (170,000 kg). This may have been because the species was easily available close to port, and has maintained a presence in the California nearshore fishery. From the 1940s to 1980s, little interest in the sheephead was shown, and catches were usually under 10,000 lb (4,500 kg). In the later 1980s, commercial fisheries began to supply live fish to Asian markets and restaurants. 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.