When you’re walking Ocean City’s beaches at sunrise or exploring the marshes at low tide, you’re sharing the coastline with some fascinating crustacean neighbors.
From the iconic blue crabs that made Maryland famous to the quirky ghost crabs that vanish into their sandy burrows, these ten crab species shape the character of our coastal ecosystem.
Whether you’re a curious beachcomber, an aspiring marine biologist, or someone who just wants to know what scuttled across your beach blanket, you’ll find everything you need to identify and appreciate the crabs that call Ocean City home.
1. Blue Crab
The blue crab (Callinectes sapidus) reigns as Maryland’s most celebrated crustacean, and for good reason. You’ll recognize these beauties by their striking blue claws and olive-green shells that can span up to 9 inches across.
The name Callinectes sapidus actually means “beautiful swimmer that is savory”—a fitting description for a crab that’s both gorgeous and delicious.
Where You’ll Find Them: Blue crabs thrive in the brackish waters of Ocean City’s bays, particularly around marsh grasses, piers, and shallow flats. Peak season runs from April through November, with the largest hauls happening in summer months when water temperatures rise above 60°F.
Pro Tip: Watch for female blue crabs with red-tipped claws—they’re called “sooks” in local waterman lingo and are protected during certain seasons to maintain healthy populations.
These opportunistic feeders consume everything from small fish and oysters to marsh grass and other crabs. The Chesapeake Bay supports one of the world’s most productive blue crab fisheries, contributing over $100 million annually to Maryland’s economy.
You’ll often spot recreational crabbers along Ocean City’s bulkheads using chicken necks tied to strings—a time-honored method that works surprisingly well.
2. Atlantic Ghost Crab
The Atlantic ghost crab (Ocypode quadrata) earns its spooky name honestly. These pale, sand-colored crabs seem to materialize from nowhere and disappear just as quickly into their burrows. With eyes perched on tall stalks and bodies that can reach 2 inches across, they’re built for speed and awareness.
Ghost crabs are primarily nocturnal, though you might spot them during overcast days or at dusk when they emerge to hunt.
They’re remarkable athletes, capable of running up to 10 miles per hour—faster than most people can sprint in sand. Their diet includes mole crabs, coquina clams, beach insects, and even turtle hatchlings.
Key Insight: Look for their distinctive burrow openings in the dry sand above the high tide line. These can extend 3-4 feet deep and often feature a small pile of excavated sand nearby. Each crab typically maintains a home burrow where it retreats during the day.
The ghost crab’s coloration changes subtly to match its surroundings, helping it blend into Ocean City’s sandy beaches. During breeding season in late spring and summer, you might observe males performing courtship displays outside burrows, tapping their legs in rhythmic patterns to attract females.
3. Fiddler Crab
Fiddler crabs (Uca pugnax and Uca minax) put on one of nature’s most entertaining shows in Ocean City’s salt marshes. Males sport one dramatically oversized claw—sometimes half their body weight—while the other remains tiny and functional. This “fiddle” claw serves no feeding purpose; instead, it’s a signal flag for attracting mates and warning rival males.
Common Mistake: Don’t assume the big claw makes males better fighters. If a male loses his major claw, the minor one grows to take its place, and a new minor claw develops on the opposite side.
You’ll find two species around Ocean City. The marsh fiddler crab (Uca pugnax) prefers high marsh areas with muddy substrate, while the red-jointed fiddler (Uca minax) ventures into fresher water where marsh and river meet. Both species excavate complex burrow systems that actually benefit marsh health by aerating soil and cycling nutrients.
During low tide, thousands of fiddlers emerge to feed, creating a moving carpet across the marsh surface. They use their small claws to pick up sediment and sort through it, extracting algae, bacteria, and organic matter. When threatened, they vanish into burrows with remarkable coordination—an entire colony can disappear in seconds.
4. Green Crab
The green crab (Carcinus maenas) represents one of the ocean’s most successful invaders. Originally from Europe, this species arrived in North American waters in the early 1800s and has been expanding its range ever since.
While called “green,” these crabs actually display colors ranging from green to orange to red, depending on their molt cycle.
| Feature | Green Crab | Native Blue Crab |
|---|---|---|
| Shell Width | Up to 3.5 inches | Up to 9 inches |
| Claw Shape | Uniform, slightly serrated | Bright blue, pointed |
| Habitat Preference | Rocky shores, jetties | Sandy/muddy bottoms |
| Native Status | Invasive | Native species |
| Economic Impact | Damages shellfisheries | Supports major fishery |
Green crabs cause significant ecological and economic damage by preying on young clams, oysters, and mussels. A single crab can consume dozens of juvenile bivalves daily. You’ll most often encounter them around Ocean City’s jetties and riprap, where they hide among rocks during high tide.
Important Note: Scientists and resource managers actively monitor green crab populations along Maryland’s coast. Some regions have implemented trapping programs to control their numbers and protect native shellfish beds.
Despite their invasive status, green crabs demonstrate impressive adaptability. They tolerate wide temperature ranges, can survive in salinity from nearly fresh to full seawater, and reproduce prolifically. Each female can produce 185,000 eggs per season.
5. Lady Crab
The lady crab (Ovalipes ocellatus) might seem delicate with its spotted purple-gray shell, but this species is an aggressive predator and surprisingly fast swimmer. Its paddle-shaped back legs allow it to swim through the water column—an unusual ability among Ocean City’s crab species.
You’ll recognize lady crabs by the distinctive leopard-like spots covering their carapace, which can span up to 3 inches. Five sharp spines line each side of their shell, giving them a fierce appearance that matches their temperament. Handle with caution if you encounter one, as they won’t hesitate to use those surprisingly strong claws.
Lady crabs bury themselves in sandy bottoms with only their eyes and antennae exposed, ambushing small fish, worms, and mollusks that venture too close. They’re most active during summer months when water temperatures peak. Unlike blue crabs that prefer estuarine conditions, lady crabs favor the higher salinity found in Ocean City’s coastal waters.
Pro Tip: Surf anglers occasionally catch lady crabs while fishing from the beach—they’ll grab bait meant for fish. Despite their feisty nature, they’re edible and considered quite tasty by those willing to deal with their small size.
6. Sand Crab (Mole Crab)
Sand crabs (Emerita talpoida)—also called mole crabs—barely look like crabs at all. These egg-shaped crustaceans lack the typical sideways-walking crab body plan. Instead, they’re built for burrowing backward into sand at impressive speeds, disappearing within seconds as waves recede.
If you’ve ever dug your toes into wet sand at the water’s edge and felt something tickle your foot, you’ve probably encountered a sand crab. They live in the swash zone where waves constantly break, moving up and down the beach with the tides.
When a wave washes over them, they extend feathery antennae to filter plankton and organic particles from the receding water.
Identification Checklist:
- Smooth, oval shell (0.5-1.5 inches)
- No visible claws
- Long, feathery antennae
- Pale tan to gray coloration
- Found exclusively in wave zone
Sand crabs serve as a crucial food source for shorebirds, surf fish, and sea turtles. If you watch sanderlings racing along the water’s edge, they’re likely probing for these nutritious morsels.
Despite constant predation pressure, sand crab populations remain stable due to their prolific breeding—females can carry thousands of bright orange eggs beneath their bodies.
These harmless creatures make excellent subjects for kids interested in marine life. They won’t pinch, and you can observe their fascinating filtering behavior by holding one gently in shallow water and watching its antennae deploy.
7. Horseshoe Crab
The horseshoe crab (Limulus polyphemus) isn’t a true crab at all—it’s more closely related to spiders and scorpions. These living fossils have remained virtually unchanged for 450 million years, predating dinosaurs by 200 million years.
You’ll most likely encounter horseshoe crabs during late spring and early summer when they come ashore to spawn. Males clasp onto larger females as they crawl up beaches during high tides, particularly around new and full moons.
Females dig nests in sandy areas and deposit thousands of greenish eggs, which serve as critical food for migrating shorebirds.
| Life Stage | Characteristics | Duration |
|---|---|---|
| Egg | Greenish, pea-sized | 2-4 weeks |
| Larva | Transparent, no tail | 1 year |
| Juvenile | Miniature adult appearance | 9-10 years |
| Adult | Full size (females 18-19 inches) | Up to 20+ years |
Key Insight: Never pick up a horseshoe crab by its tail. If you find one flipped upside down, gently grasp the sides of the shell and return it to the water. The tail is a rudder, not a weapon—these creatures are completely harmless.
Horseshoe crabs possess bright blue blood containing copper-based hemocyanin instead of iron-based hemoglobin. Medical researchers harvest small amounts of this blood to create Limulus Amebocyte Lysate (LAL), used to test vaccines and medical devices for bacterial contamination.
This has made horseshoe crabs invaluable to human medicine, though conservation efforts ensure sustainable practices.
8. Mud Crab
Mud crabs (Panopeus herbstii) hide in plain sight throughout Ocean City’s marshes, oyster reefs, and mudflats. These small, dark crabs rarely exceed 1.5 inches across, but they play an outsized role in coastal ecosystems. Their black-tipped claws provide a reliable identification feature.
You won’t find mud crabs in the middle of sandy beaches—they prefer structured habitats where they can seek shelter. Look for them under rocks, within oyster shells, among marsh vegetation, or burrowed into muddy substrates. They’re particularly common around dock pilings where barnacles and mussels provide both food and cover.
Despite their diminutive size, mud crabs are formidable predators of juvenile oysters and barnacles. They use their robust claws to chip away at shells and access the soft tissue inside.
This has earned them a mixed reputation—while they’re natural parts of healthy ecosystems, they can impact oyster restoration efforts when populations explode.
Behavioral Patterns:
- Most active during high tide
- Primarily nocturnal feeders
- Aggressive toward other crabs
- Can tolerate wide salinity ranges
- Often found in groups
Mud crabs themselves serve as prey for fish, larger crabs, and wading birds. They reproduce throughout warm months, with females carrying orange egg masses beneath their abdomens. If you’re exploring tide pools or oyster reefs, you’ll likely spot several mud crabs scuttling for cover.
9. Stone Crab
Stone crabs (Menippe mercenaria) rarely venture into Ocean City’s immediate coastal waters, but you might encounter them in deeper offshore areas or occasionally near inlet jetties.
These stocky crabs are built like tanks, with enormously powerful claws that can exert over 19,000 pounds of force per square inch.
The stone crab fishery operates under unique regulations—only one claw can be harvested from each crab, which is then returned alive to the water.
Remarkably, stone crabs can regenerate lost claws, though it takes about 18 months for a claw to reach harvestable size again. This sustainable practice allows the same population to support the fishery year after year.
Stone Crab vs. Mud Crab Quick Comparison:
| Feature | Stone Crab | Mud Crab |
|---|---|---|
| Size | Up to 5 inches wide | Up to 1.5 inches wide |
| Claw Size | Massive, asymmetrical | Small, proportional |
| Habitat | Deeper offshore waters | Shallow marshes, reefs |
| Commercial Value | High (harvested claws) | None (too small) |
Stone crabs prefer rocky or shell-bottom habitats where they can wedge into crevices for protection. Their diet consists mainly of oysters, mussels, and other hard-shelled prey they can crack with their powerful claws. The right claw typically grows larger than the left and serves as the primary crushing tool.
While stone crabs aren’t common in Ocean City proper, charter boats fishing offshore structures occasionally encounter them. The meat from their claws is considered a delicacy, with a sweet, firm texture that commands premium prices at seafood markets.
10. Spider Crab
Spider crabs (Libinia emarginata)—also called portly spider crabs—look like something from a science fiction movie.
Their triangular bodies sport long, spindly legs that give them a creepy-crawly appearance. Don’t let the alien looks fool you, though—these are gentle creatures that rarely pinch even when handled.
You’ll most often see spider crabs washed up on Ocean City beaches after storms or spot them while snorkeling around jetties and offshore structures.
They prefer deeper waters but venture into shallower areas during warmer months. Their bodies can reach 4 inches across, but their legs span considerably wider, up to 12 inches tip to tip.
Fascinating Adaptations:
- Natural decorators: attach seaweed, sponges, and other debris to their shells for camouflage
- Slow-moving scavengers that feed on dead animals and organic matter
- Relatively long-lived, potentially reaching 10+ years
- Females carry eggs from late spring through summer
Spider crabs practice a behavior called “decoration” where they carefully select algae, bryozoans, and other living organisms to attach to hooked setae (hairs) covering their shells. This living disguise grows along with the attachments, creating highly effective camouflage. When spider crabs molt, they must redecorate their new shells.
Despite their intimidating appearance, spider crabs make poor eating compared to blue crabs—their meat yield is low, and the long legs make processing tedious.
However, they serve important ecological roles as scavengers, cleaning up dead organisms from the ocean floor. Watch for them in tide pools during very low tides, where they move with surprising grace despite their awkward appearance.
Ocean City’s diverse crab population reflects the rich ecosystem where Chesapeake Bay meets the Atlantic Ocean. From the commercially important blue crab to the ancient horseshoe crab, each species contributes to the coastal environment in unique ways.
Next time you’re beachcombing or exploring tidal areas, take a moment to observe these fascinating crustaceans—you’re witnessing millions of years of evolution perfectly adapted to life at the water’s edge.
Whether you’re here for world-class crabbing, wildlife photography, or simply enjoying the beach, understanding these ten crab species will deepen your connection to Ocean City’s remarkable coastal heritage.
