Velvet Swimming Crab: Unraveling the Mysteries of This Deep-Sea Dweller Hiding in Plain Sight!

The velvet swimming crab (Necora puber), also known as the edible crab, is a captivating crustacean residing primarily in the eastern Atlantic Ocean, from Norway to Morocco. Despite its name, this fascinating creature prefers shallow coastal waters, often lurking among rocky reefs and seaweed beds, displaying remarkable adaptability and resilience in its chosen habitat.

Velvet swimming crabs are easily identifiable thanks to their velvety carapace – the hard upper shell covering their bodies. This distinctive feature arises from a dense covering of fine hairs or setae that give it a soft, almost fuzzy appearance. The color can vary depending on factors like age, sex, and location but typically ranges from reddish-brown to dark green, with distinct white spots adorning its carapace.

Anatomy and Physiology: A Closer Look

These crabs are relatively small compared to their land-dwelling relatives, averaging around 60mm in carapace width for males and a bit smaller for females. They exhibit the classic crab anatomy:

Cephalothorax: This fused head and thorax region houses essential organs like the brain, heart, and gills.
Abdomen: Tucked beneath the cephalothorax, the abdomen is folded and tucked away, contributing to their streamlined profile while swimming.
Legs: Ten legs in total – eight walking legs for scuttling along the seabed, and two powerful claws used for grasping prey and defense.
Eyes: Positioned on stalks, their compound eyes offer a wide field of vision for spotting both predators and potential meals.

A Life Underwater: Feeding Habits and Ecology

Velvet swimming crabs are omnivorous scavengers, consuming a wide variety of food sources. They’ll happily devour anything they can catch – from mussels, clams, and worms to smaller crustaceans and fish carcasses. They’re also opportunistic feeders, taking advantage of whatever washes up on the seabed, including decaying plant matter and algae.

Reproduction: A Delicate Dance

These crabs engage in a fascinating courtship ritual, which involves intricate movements and chemical signaling. The males compete for females by waving their claws and displaying vibrant colors to attract mates. Once a female selects a suitor, they mate, and the female carries fertilized eggs beneath her abdomen until they hatch into tiny larvae.

These planktonic larvae drift in ocean currents, undergoing several molts and transformations before settling onto the seabed as juvenile crabs.

Ecological Importance: Balancing Act

Velvet swimming crabs play a crucial role in maintaining the balance of their marine ecosystems. As scavengers, they help to clean up dead organisms and recycle nutrients back into the environment. They also serve as prey for larger fish and crustaceans, contributing to the complex food web that sustains ocean life.

Prey: Mussels, clams, snails, sea stars, anemones, worms, small crustaceans, fish carcasses
Predators: Larger crabs, lobsters, fish (cod, hake), seabirds

Interesting Facts: Unveiling Crab Quirks

Swimming Prowess: These crabs aren’t just aptly named; they are indeed skilled swimmers! Their flattened bodies and specialized swimming legs allow them to move gracefully through the water column, even venturing into deeper waters for short periods.
Shedding Shells: Like all crustaceans, velvet swimming crabs shed their exoskeletons periodically as they grow. This process is called molting and leaves them vulnerable until their new shell hardens.
Color Change Camouflage: They can adjust the intensity of their coloration depending on their surroundings, providing a degree of camouflage against predators.

Conservation Status: Ensuring Future Generations

Velvet swimming crabs are not currently considered endangered. However, like many marine species, they face threats from habitat degradation, overfishing, and pollution. Sustainable fishing practices and responsible waste management are crucial for ensuring the continued health of these fascinating creatures and their delicate marine ecosystem.