Meet the California Spiny Lobster

Fast Facts:

  • Common name: California Spiny Lobster
  • Scientific name: Panulirus interruptus
  • Average Size: 11.8 inches
  • Lifespan: Difficult to determine. However, individuals have been known to live up to 50 years.

Physical Description:

The California spiny lobster is a large ten-legged crustacean. They are red to orange in color with spines covering their hard shell. Unlike the American lobster, spiny lobsters do not have claws. Instead they have two large antennae which extend out of their face. These antennae can be twice as long as their bodies and are covered in spines and small sensory hairs.

Geographic Range:

This lobster ranges from Monterey Bay, California to Manzanillo, Mexico and has a small isolated population at the northwestern corner of the Gulf of California. The majority of the population can be found between Point Conception, California (in Santa Barbara County) and Magdalena Bay in Baja California, Mexico.


California spiny lobster prefers to live in rocky reef habitats where it can hide in cracks and crevices. It is also found in kelp forests and surf grass beds as well as the occasional tidepool. It’s depth ranges from very shallow waters to 240 feet for more!

A large portion of the California spiny lobster population makes annual offshore-nearshore migrations stimulated by changes in water temperature and winter storms. During the cold fall and winter months, most male and female lobsters are found offshore at depths of 50 feet or more. In late March, April, and May, the lobsters move into warmer nearshore waters less than 30 feet deep.  These warmer nearshore temperatures shorten the development time for lobster eggs and also have a more plentiful food supply.


During the day, California spiny lobsters typically hide in crevices and caves called “dens”. They usually share these dens with other lobsters or other animals such as moray eels. At night, they leave their dens in search of food.

A group of lobsters eating a dead shovelnose guitarfish

California spiny lobsters are omnivorous, meaning they will eat pretty much anything ranging from algae and dead animals to a wide variety of marine invertebrates such as snails, sea urchins, clams, and mussels. They may even resort to cannibalism and prey on injured or recently molted lobsters (lobsters that have shed their shells). Lobsters have hard mouthparts called mandibles that allow them to chip away at the hard shells of many of these invertebrates.

While out searching for food, they also have to be careful of predators, including California sheephead, cabezon, kelp bass, octopuses, California moray eels, horn sharks, leopard sharks, rockfish, and giant sea bass. (Yes, they share their dens with morays but can also be eaten by them depending on size.)

If a predator comes too close to their den you will often see them attempt to scare the predator off by waving their antennae or hitting the predator. If that doesn’t work they can create a loud clicking/rasping noise by rubbing the base of their antennae against a file-like spot near their eyes. And if all these very intimidating tricks fail, then they will resort to fleeing by rapidly flexing their tails, propelling themselves quickly backwards and away from danger. In the unlucky chance that they are caught, they are also able to drop and later regrow their appendages in a last chance escape.

Reproduction and Growth:

Spiny lobsters mate from November to May. During mating, the male attaches a putty-like sperm packet, called a spermatophore, to the bottom of the female’s carapace between the last pair of legs. The female will carry this sperm packet around till she is ready to use it around May and June when she will use a small claw on her last pair of legs to scratch it open and fertilize her eggs before attaching them to the underside of her tail. She will carry the eggs for about 10 weeks. During this time, she is generally in shallow water, less than 30 feet deep. The number of eggs can range between 50,000 and 800,000 eggs and depends on the size of the female. Larger females are able to produce and carry significantly more eggs than smaller lobsters.

Spiny lobster eggs hatch into tiny, transparent larvae with flattened bodies and spider-like legs. They are planktonic, drifting wherever the currents take them. They may drift up to 350 miles offshore, and are found from the surface to depths of over 400 feet.

Lobsters must shed their shell to grow. This is known as ‘molting’. Before a lobster molts, it forms a new soft shell under the old one. Once ready, the lobster will spilt the old shell between the carapace and tail and pull it’s entire body out from the old shell. The lobster then takes in water to expand the new soft shell and give it room to grow. It takes a few days for the shell to harden, therefore during this time they are more vulnerable to predation and hide away in a den.

Both male and female lobsters generally reach sexual maturity in 5 or 6 years and reach legal size around 7 to 11 years. Mature male lobsters grow faster, live longer, and reach larger sizes than females.

Stay tuned for our next post about the fishery!