Rock Crab

This crustacean is a decapod, though most people refer to it as the red rock crab. Found along the Pacific Coasts, it has become a beloved dish in California, allowing it to be sold commercially and fished by locals.

The rock crab molts throughout its life, shedding its former shell. Typically, younger crabs molt multiple times in the same year. It is not until they are about four inches in width that they reduce their molting to an annual occurrence.

5 Incredible Rock Crab Facts

Here are a few interesting facts about this crustacean.

• This species has five pairs of legs, though only the two in front are claws.
• The shell is round and flat, helping it hide beneath the sand and within rocks.
• Though they can be quick in short movements, this crustacean doesn’t move much.
• The hair-like structures on the legs allow it to feel movement and go after nearby prey.
• The average wild rock crab lives to be 5-6 years old, but the right environment can prolong their life to nearly 8 years.

Classification and Scientific Name

There are three species of rock crabs found along the Pacific coast of the US: the red, brown, and yellow rock crabs. They are part of the Cancridae family and the Malacostraca class.

Species

While there aren’t many other species of rock crab, there are a variety of colors, which include:

• Yellow rock crabs (Metacarcinus anthonyi): Sandy areas along the coast are the primary habitat for yellow rock crabs.
• Red rock crabs (Cancer productus): Most commonly sold by fisheries and other commercial settings. They are primarily found on the Pacific Coast and sold in California.
• Brown rock crabs (Romaleon antennarium): They are found mostly on reefs. There’s no real size difference between them, but they are primarily differentiated by their preferred habitat and color.

Rock Crab Appearance

This species typically has a white to red-brown shell, which is why it is also known as the red rock crab. The body is rather chunky and heavy, but the most identifiable feature of the animal is its huge claws. Apart from their massive size, the claws are a brown-black color and have lighter-colored tips, making them easy to recognize. The claws are necessary for breaking down the shells of their prey, like snails.

The average rock crab is about 13 ounces in weight, and its shell reaches a maximum size of 4 inches. Their claws and bodies have a lot of meat, becoming flaky when cooked.

Distribution, Population, and Habitat

Due to how abundant rock crab eggs can be, it is hard to determine how many exist in the world. However, considering that over half a million pounds of this species are fished in just California every year, the numbers are fairly high, and they are currently “not extinct” (according to the IUCN). The NOAA’s current stock status shows that they are not overfished.

The majority of this species is found in rocky reef areas, though yellow rock crabs are specifically found in sandy areas of the coast. Typically, they’ll prefer bays, gravel, rocky substrates, estuaries, sand, and mud, living typically at 298 feet in the waters of California. However, away from that area of the coast, rock crabs will go deeper into the water for hunting and scavenging.

Primarily, this crustacean is found in marine environments along the Pacific coast.

Predators and Prey

When it comes to mealtime, this species will grab just about anything they can clamp their claws down on. As scavengers, they aren’t very picky, but they’ll mostly look for other invertebrates to eat. They’ll even indulge in other crabs and dead fish.

What does the Rock Crab eat?

As a scavenger, the diet of this crustacean primarily depends on where it is. Most of the time, they’ll enjoy worms, clams, mussels, and other invertebrates, breaking through their shell with ease. They’ll also indulge in barnacles, sea cucumbers, and amphipods. However, if a meal like a dead fish is available to them, they’ll dine on that too.

What eats Rock Crabs?

One of the biggest predators of this species is humans. Because of all of the meat that they offer, humans will fish for the crabs for different dishes. They are also hunted by crabs, fish, gulls, seabirds, and kelp bass. There’s also one breed of sea otters – Enhydra lutris – that specifically uses rock crabs as the main food in their diet.

Reproduction and Lifespan

When this species mates, it usually occurs from October to June because the female has a softer shell at this time. When she is in the molting stage, she won’t be as vulnerable as you might think because the male protects her.

About three months after this time, the female produces eggs in her abdominal sac. Before the eggs can be laid, the female migrates to where the eggs will eventually be hatched, hiding for about 12-13 days in the dirt. The female rock crab has the potential to lay up to 100,000 eggs.

They are fertilized by a sperm packet that the female stores during the mating time with the male. Once she lays the eggs, she’ll carry the eggs on her own body for about 6-8 weeks before they are ready to hatch. Baby rock crabs are opportunistic omnivores, eating small crustaceans, worms, algae, and other plant matter.

Fishing and Cooking

These are some of the most common species of crab for California fishermen, whether they are fishing for sport or commercial purposes. The primary place in California that they fish from is Morro Bay South. However, the California rock crab fishery seeks out several types: yellow, brown, and red. On average, this fishery takes on over one million pounds of rock crab annually.

Rock crab legs can have a great taste, no matter how they are seasoned. Steaming the legs with beer and Old Bay seasoning brings out a bold and pub-style taste, while even just the right dipping sauce can change the flavor. Crab legs are always a delicacy, and the tender flesh is perfect for any taste.