The spotted catshark (Scyliorhinus canicula) is a small shark commonly found in the Northeast Atlantic Ocean and the Mediterranean Sea. This widespread bottom-dweller is one of the most abundant elasmobranchs in its range. Its presence is often indicated by distinctive egg cases, which frequently wash ashore.
Physical Characteristics and Habitat
The spotted catshark has a slender body, typically 50 to 70 centimeters long, though some individuals can grow up to 1 meter. Its body is sandy or greyish-brown, adorned with numerous dark brown spots that provide camouflage against the seabed. Its skin feels rough due to dermal denticles, small tooth-like scales. It has a blunt head with a rounded snout and a lighter greyish-white underside.
This shark inhabits continental shelves and upper continental slopes, preferring sandy, gravelly, or muddy seafloors. Its distribution extends from the coasts of Norway and the British Isles south to Senegal, including the entire Mediterranean and Adriatic Seas. While commonly found in depths of a few meters, it can descend to approximately 100 meters in the Northeast Atlantic, 400 meters in the Mediterranean, and even up to 780 meters in the Eastern Ionian Sea.
Diet and Hunting Behavior
The spotted catshark is an opportunistic predator with a varied diet that shifts as it matures. Younger individuals primarily consume small crustaceans like shrimp and crabs. As they grow, their diet expands to include larger prey such as hermit crabs, cockles, and various mollusks.
Adult spotted catsharks feed on a wide array of bottom-dwelling organisms, including decapod crustaceans, gastropod mollusks, cephalopods, marine worms, and small fish. These sharks are largely nocturnal hunters, resting on the seafloor during the day before actively foraging at night.
Reproduction and Life Cycle
The spotted catshark is oviparous, meaning it lays eggs. The eggs are encased in distinctive, leathery capsules known as “mermaid’s purses,” which are typically tubular and measure about 4 to 6 centimeters long. Each corner of these egg cases features long, curly tendrils.
These tendrils anchor the egg cases securely to structures on the seafloor, such as seaweed, sponges, or sessile invertebrates, preventing them from being swept away by currents. The embryo develops inside the protective casing for 5 to 11 months, with the duration influenced by water temperature, often hatching after 8 to 9 months. Juveniles emerge from the egg cases measuring approximately 9 to 10 centimeters. Spawning can occur throughout the year. Males typically live for about 11 years, while females can live up to 12 years.