Panulirus interruptus
California spiny lobster

California spiny lobsters are found on the Pacific coast of North America from Monterey Bay, California (though rarely found north of Point Conception) to Baja California, Mexico. They are occasionally found within the Gulf of California. ("Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest): Spiny Lobster", 1988; Holthuis, 1991)

California spiny lobsters prefer rocky reef habitats, where they den in crevices. They occasionally are found in tide pools, but are more frequently found in deeper water up to 65 m in depth. California spiny lobsters seek the cover of kelp forests and surf grass. (Holthuis, 1991; Hovel and Lowe, 2007)

California spiny lobsters average 908 g in mass and range from 454 to 2270 g. On average, they are 30 cm long, though they can measure as large as 90 cm in length. Males are generally larger than females. The body of California spiny lobsters consists of a cephalothorax, which includes the head and legs, and an abdomen and tail, which has paddle-like swimming structures. The exoskeleton is generally red to orange in color with black markings. Spiny projections are located on the carapace (upper shell) and sides of the abdomen. Their two primary antennae may equal the length of their body. Their compound eyes rest on short stalks protected by curved spines. Unlike Maine lobsters in which the first pair of thoracic appendages are specially modified as chelipds (claws), all five pairs of appendages of California spiny lobsters are used for walking. (California Sea Grant, 2008; Holthuis, 1991)

Female California spiny lobsters produce between 50,000 and 800,000 eggs per brood, which are carried underneath the abdomen by pleopods until they hatch. After hatching, young are released into the water column as phyllosoma larvae. California spiny lobsters undergo 11 distinct phyllosoma stages. They range in size from 1.2 to 1.5 mm in Stage I and from 26 to 31.2 mm in Stage XI. During these stages, they are completely planktonic, drifting with water currents. This is the most hazardous part of the life cycle. After growth and development in the water column, larvae metamorphose into puerulus, assuming the body characteristics of the adult. Puerulus settle to the seafloor and grow into juvenile lobsters. (Lindberg, 1955)

Mating of California spiny lobsters generally begins under moderate sea surface temperatures, usually during upwelling conditions. Mating takes place in water 15 to 30 m deep from December through March. During copulation, male California spiny lobsters deposit spermatophores on the sternum of a female. Females then move inshore to shallow water (usually less than 15 m in depth) and extrude 50,000 to 800,000 eggs. These eggs are fertilized by sperm released from the spermatophores, and they attach in masses to feathery pleopods beneath the abdomen of females. ("Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest): Spiny Lobster", 1988; Diaz-Arrendondo and Guzman, 1995)

Mature California spiny lobsters mate between December and March and spawn between March and August. Spawning occurs once a year and reproduction peaks in June. Females produce 50,000 to 800,000 eggs with each brood. Females reach sexual maturity at 5 to 9 years of age, while males reach sexual maturity at 3 to 6 years of age. ("Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest): Spiny Lobster", 1988; Diaz-Arrendondo and Guzman, 1995)

After spawning in late spring, female California spiny lobsters hold their fertilized eggs in their abdomen until they hatch. Females have feathery appendages that carefully hold the eggs as well as small pincers on the fifth pair of walking legs used to groom and maintain the egg mass. (Lindberg, 1955)

Lifespan of California spiny lobsters is difficult to determine because their exoskeleton is periodically molted. Individuals in the wild have been known to live between 11 and 30 years, while in captivity they have survived 8 to 25 years. ("Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest): Spiny Lobster", 1988)

California spiny lobsters are nocturnal, hiding in crevices and dens during the day to avoid predators. They are semi-social, sharing dens with conspecifics. At night, spiny lobsters emerge to forage, traveling up to 600 m in search of food. (Case, et al., 1985; Diaz-Arrendondo and Guzman, 1995)

California spiny lobster constantly moves from place to place, resting in a den during the day and traveling to find food at night. They have been known to travel up to 600 m in search of food. It is unclear whether California spiny lobsters return to the same den. (Case, et al., 1985)

California spiny lobsters use visual sensing to detect predators, and chemical stimuli are perceived through the small antennae. Sensory hairs cover their appendages, including the long antennae, which are used for tactile perception. They also rub the base of their antennae against a file-like surface under each eye to generate strident warning noises to scare off potential predators. (Lindberg, 1955; Staaterman, et al., 2009)

California spiny lobsters are omnivorous bottom feeders that scavenge dead animals, algae, and detritus. They also consume invertebrates such as the species of mussel Mytilus californianus and urchins Strongylocentrotus franciscanus and S. purpuratus. California spiny lobsters use their mandibles to chip away at the shells of M. californianus In the winter, California spiny lobsters occasionally eat coralline algae. Their diet varies seasonally, and males generally consume a wider variety of prey than females. (Case, et al., 1985; Diaz-Arrendondo and Guzman, 1995; Eminike, et al., 1990; Lindberg, 1955)

To ward off predators, California spiny lobsters produce rasping noises by stridulating the base of the antennae against a file-like eyespot. They also attempt to flee, swimming backwards by repeatedly and rapidly flexing their abdomen. If caught by a predator, decopods self-autotomize (purposely cast off an appendage) to escape. California spiny lobsters are preyed upon by octopuses, California sheephead, cabezon, kelp bass, California moray eels, horn sharks, leopard sharks, giant sea bass, and various rockfish. Humans also fish for California spiny lobsters. (Barsky, et al., 2003; Lindberg, 1955; Staaterman, et al., 2009)

California spiny lobsters are important coastal nearshore predators that have been shown to regulate the population of several key invertebrate species such as purple urchins and the mussel species Mytilus californianus. They also act as hosts to sponges, hydroids, barnacles, serpulida, krill-like amphipods and nemertean (Carcinonemertes wickhami). (Eminike, et al., 1990; Lafferty, 2004; Lindberg, 1955)

California spiny lobsters have supported recreational and commercial fishing in Southern California since the late 1800s. From 1916 until 1942, annual commercial landings ranged between 90 to 180 metric tons, and in 2003 over 270 metric tons were harvested. The magnitude and impact of the recreational fishing for this species is unknown. (Barsky, et al., 2003)

There are no known adverse effects of California spiny lobsters, although their spiny carapace can cut an unprotected hand of sport fishermen.

California spiny lobsters have not been evaluated by the IUCN or the US Fish and Wildlife Service. However, fishing removes considerable numbers of this species which may not be sustainable.