Types of Crabs in South Carolina: Guide to Coastal Species You’ll Find

South Carolina’s coastal waters and marshlands host an impressive variety of crabs that have thrived in these environments for centuries.

Whether you’re walking along sandy beaches at sunset or exploring tidal marshes during low tide, you’ll likely encounter these fascinating creatures scuttling across the sand or disappearing into their burrows.

South Carolina is home to over ten distinct crab species, from the commercially prized blue crab to the tiny fiddler crabs that wave their oversized claws along marsh edges.

Each species has adapted to specific coastal habitats, creating a diverse ecosystem where some crabs swim through brackish waters while others burrow deep into beach sand or claim empty shells as mobile homes.

From the ancient horseshoe crab that’s remained virtually unchanged for millions of years to the colorful calico crab hiding among offshore reefs, you’ll discover how these crustaceans play vital roles in South Carolina’s coastal food web.

Understanding these species will enhance your next beach visit and help you appreciate the complex marine life that makes the Palmetto State’s coastline so remarkable.

Blue Crab

The blue crab (Callinectes sapidus) is South Carolina’s most famous crab species. Its scientific name means “beautiful, savory swimmer” in Latin.

You can easily spot blue crabs by their wide, flat shells and bright blue claws on males. Females have orange-tipped claws instead. These crabs grow up to 9 inches across and have paddle-like back legs for swimming.

Physical Features:

• Five pairs of legs total
• Sharp spines on each side of the shell
• Males are larger than females
• Olive-brown back with blue front

Blue crabs live in South Carolina’s estuaries, marshes, and coastal waters. Young crabs grow up in shallow marsh areas, while adults prefer deeper waters. They move between fresh and salt water throughout their lives.

The mating season runs from February to November. Females only mate once in their lifetime, storing sperm to fertilize eggs for up to two years. You’ll find egg-carrying females in Charleston Harbor from April through October.

Diet and Behavior:
Blue crabs eat almost anything they find. Their menu includes fish, other crabs, mollusks, and dead plants and animals. They bury themselves in mud during cold winter months.

You can catch blue crabs using crab pots, drop nets, or dip nets. Commercial fishers also harvest them with trawl nets. The population in South Carolina waters remains stable and healthy.

Soft-shell blue crabs are highly prized when they molt their hard shells. This happens quickly, making timing important for crabbers.

Stone Crab (Menippe mercenaria)

You’ll find stone crabs thriving in South Carolina’s salt marshes and coastal waters. These robust crabs have oval-shaped shells that reach up to 5.5 inches wide.

Physical Features
Stone crabs are easy to spot with their powerful, unequal claws. One claw grows larger than the other, and both have distinctive black tips. Their shells show brown, tan, or reddish-purple colors.

Where to Find Them
You can discover stone crabs in shallow coastal areas, especially around:

• Salt marshes
• Rocky jetties
• Oyster beds
• Seagrass flats

They prefer areas with good water flow and plenty of hiding spots.

Behavior and Diet
These crabs are opportunistic feeders that hunt at night. They use their strong claws to crush oysters, mussels, and other shellfish. During the day, they hide in burrows or under rocks.

Natural Predators
Stone crabs face threats from several predators. Octopuses are their main enemy and can easily handle their powerful claws. Large fish also prey on younger stone crabs.

Harvesting Notes
Stone crab claws are harvested commercially in South Carolina. The practice involves removing one claw and releasing the crab, which can regenerate the lost claw over time. This sustainable method helps maintain crab populations while providing a valuable seafood resource.

You might encounter stone crabs while crabbing or exploring tidal pools along South Carolina’s coast.

Atlantic Ghost Crab (Ocypode quadrata)

You’ll find the Atlantic ghost crab along South Carolina’s beaches year-round. This is the only ghost crab species on the East Coast of the United States.

These crabs get their name from their pale, ghostly appearance. Adults are straw-colored or grayish-white and measure about 2 inches wide when fully grown.

Physical Features:

• Stalked eyes that rotate 360 degrees
• Two claws (one usually larger)
• Square-shaped body
• Long, sturdy legs built for speed

You can spot their deep burrows in the sand above the high tide line. Older crabs dig farther inland, sometimes up to 1,300 feet from the water. Their burrows can reach 4 feet deep.

Ghost crabs are incredibly fast runners. They’re among the fastest land creatures without backbones, reaching speeds over 3 feet per second.

These crabs are most active at night. During the day, they stay cool in their sandy burrows.

What they eat:

• Clams and mole crabs
• Sea turtle eggs and hatchlings
• Dead plant and animal matter
• Small insects
• Other crabs

Ghost crabs must return to the ocean to wet their gills. You’ll often see them making quick trips to the water’s edge.

Their breeding season peaks during summer months. Females release their eggs directly into the ocean where they develop.

Human foot traffic and vehicles on beaches can harm ghost crab populations by crushing burrows and disturbing their habitat.

Horseshoe Crab (Limulus polyphemus)

Despite their name, horseshoe crabs aren’t true crabs at all. You’ll find these unique creatures are more closely related to spiders and scorpions than to actual crabs.

Physical Features

• Hard, dome-shaped shell (carapace)
• Long, pointed tail (telson)
• Seven pairs of legs
• Two sets of eyes
• No antennae or jaws

You can spot horseshoe crabs along South Carolina’s beaches and shallow coastal waters. They prefer soft, sandy or muddy bottoms where they can easily burrow and feed.

Spawning Season
Each spring, you’ll witness an amazing sight when these ancient creatures come ashore to mate. They arrive during high tides, especially at night during new and full moons. Females dig nests in the sand and lay thousands of green eggs.

Ecological Importance
Horseshoe crab eggs provide crucial food for migrating shorebirds like red knots. At least 20 bird species depend on these protein-rich eggs during their long journeys north.

Medical Uses
Their blue blood contains a special clotting agent called LAL. Medical companies use this substance to test for dangerous bacteria in vaccines and medical equipment.

Conservation Status
South Carolina protects horseshoe crabs by limiting their harvest. You need a permit to collect them, and commercial fishing for bait is banned. This helps ensure these living fossils continue thriving in our coastal waters.

Calico Crab (Hepatus epheliticus)

You’ll recognize the calico crab by its striking appearance along South Carolina’s coast. This beautiful crab displays a white shell covered with large red spots that have dark outlines.

The calico crab’s shell grows up to 3 inches wide and has an almost round shape. You might also hear locals call it the Dolly Varden crab or calico box crab.

Habitat and Distribution:

• Shallow coastal waters
• Sandy and muddy bottoms
• Chesapeake Bay to Dominican Republic range

You’ll find these crabs living in shallow waters throughout the western Atlantic. They prefer to bury themselves completely in sand or light gravel on the ocean floor.

When you’re crabbing or walking along South Carolina beaches, look for disturbed sand patches. Calico crabs hide during the day and emerge when food becomes available.

Key Characteristics:

These crabs create strong water currents when they breathe. You can observe this unique behavior if you place one in shallow water – it pumps water several inches high like a small geyser.

Calico crabs make interesting aquarium specimens because they survive well in captivity. They’ll stay buried until feeding time, then quickly emerge to grab food.

You can distinguish them from other spotted crabs by their specific red and white pattern and rounded shell shape.

Spider Crab (Libinia emarginata)

You’ll find the common spider crab along South Carolina’s coast, where this unique crustacean stands out from other local crab species. Also known as the portly spider crab or nine-spined spider crab, this Atlantic coast native has a distinctive appearance.

The spider crab’s triangle-shaped shell measures about four inches from front to back. You can identify it by the row of nine low spines along its tan-colored shell. When its legs stretch out, this crab reaches up to one foot across.

Key identifying features:

• Long, narrow legs and claws
• Beak-like snout projection
• Short eyestalks
• Males grow larger than females

You’ll notice these crabs move slowly and often appear covered in algae and debris. This isn’t dirt – it’s camouflage. The spider crab belongs to “decorator crabs” that use hook-like hairs to attach materials for protection from predators.

These crabs are scavengers with poor eyesight. They use sensitive organs on their leg tips to find food in water and mud. You might spot them feeding on starfish or other dead sea life.

Spider crabs can tolerate polluted waters better than many other species. They often walk forward instead of sideways like most crabs. When threatened, they wave their claws overhead as a warning signal.

During spring, you may observe large mating groups in shallow waters near eelgrass beds.

Lady Crab (Ovalipes ocellatus)

You’ll recognize the lady crab by its distinctive leopard-like spots scattered across its sandy shell. These purple and brown markings make it one of the most beautiful crabs you can find along South Carolina’s beaches.

Physical Features:

• Shell width up to 3 inches
• Sandy colored with dark rosette patterns
• Purple or maroon coloring on claws
• Specialized swimming legs called swimmerets

The lady crab spends most of its time buried in the sand with only its eyestalks visible. You’ll typically spot these crabs in the surf zone where waves meet the shore.

Where to Find Them:
You can encounter lady crabs from the Gulf of Mexico all the way to Massachusetts. In South Carolina, they prefer sandy intertidal areas and shallow coastal waters.

These crabs are skilled hunters and scavengers. They feed on dead fish, clams, and other crustaceans but also actively hunt living prey when the opportunity arises.

Life Cycle:
Female lady crabs carry their eggs in a spongy mass under their abdomen. The larvae hatch in early summer and drift as plankton before settling as adult crabs by fall.

Ecological Role:
Lady crabs serve as important cleanup crew members, removing decaying matter from beach environments. They also provide food for seabirds and fish, making them valuable links in South Carolina’s coastal food web.

Fun Fact: Despite their elegant name, lady crabs can be quite aggressive when threatened or handled.

Fiddler Crabs (Uca spp.)

You’ll easily spot fiddler crabs along South Carolina’s salt marshes and tidal flats by their distinctive square bodies and the males’ dramatically oversized claws. These small crabs get their name because males hold their large claw like a violin.

Male fiddler crabs develop one claw that can weigh up to 65% of their total body weight. They wave this massive claw to attract females and intimidate other males during mating season.

Three main species live along South Carolina’s coast:

You can find these crabs foraging in large groups when the tide goes out. They dig burrows up to 23 inches deep in stable marsh substrate.

Mud fiddlers are the most common species you’ll encounter. They have blue to turquoise eyestalks and yellowish-orange large claws on males.

Sand fiddlers prefer beaches and sandy areas. Their bright purple shell patches make them easy to identify.

Red-jointed fiddlers are the largest of the three. You’ll notice the distinctive red coloring on the joints of the male’s oversized claw.

These crabs play a vital role in marsh ecosystems by mixing sediment and providing food for birds and other marine animals.

Mud Crabs (Panopeus spp.)

You’ll find mud crabs hiding in South Carolina’s marshes and tidal flats. These small but mighty crustaceans play important roles in coastal ecosystems.

The Atlantic mud crab (Panopeus herbstii) is the most common species you’ll encounter. It’s also called the black-fingered mud crab because of its distinctive dark claw tips.

Physical Features:

• Maximum size: 4 cm across the shell
• Color: Muddy brown to gray
• Strong, unequal claws with black tips
• Thick, sturdy exoskeleton

You can spot these crabs in oyster reefs and muddy marsh bottoms. They hide under shells, stones, and among marsh grass during the day.

Where to Look:

• Salt marshes
• Oyster beds
• Under rocks and shells
• Tidal creek banks

Mud crabs are skilled predators with powerful claws. They crack open young oysters, clams, and snails for food. You might see them pulling hermit crabs right out of their shells.

These crabs rarely venture into open water. Instead, they prefer staying hidden in their muddy homes where they can ambush prey and avoid larger predators.

Young mud crabs serve as important food for fish, birds, and other marine animals in South Carolina’s coastal food web.

Speckled Swimming Crab (Arenaeus cribrarius)

You’ll find the speckled swimming crab along South Carolina’s sandy beaches and shallow coastal waters. These distinctive crabs range from Massachusetts down to Argentina, making them common visitors to your local shoreline.

Physical Appearance
The speckled swimming crab has a light brown or olive shell covered in white or tan round spots. Males display more vibrant colors than females. Their shell can grow 4.5 to 6 inches wide and weighs up to 1.6 ounces.

Habitat and Behavior
You can spot these crabs buried in sand with only small gaps visible for breathing. They clear sand using their claws and mouth hairs to maintain water flow to their gills. These crabs are nocturnal and prefer to hunt alone.

They live in water temperatures between 52-84°F and can be found up to 200 feet deep.

Diet and Predators
Speckled swimming crabs eat mostly dead organic matter but also hunt fish, mollusks, and other crustaceans. They use ambush tactics from their buried positions. Interestingly, they’ve been recorded capturing sea turtle hatchlings.

Sea turtles are their main predator. The crabs use their spotted coloration and spines for protection.

Commercial Importance
These crabs support important fisheries, especially along Brazil’s coast. People harvest them for meat, and their shells provide chitin for adhesives and cosmetics.