Squalus
Squalus is a genus of dogfish sharks, belonging to the family Squalidae. They are found in all oceans, inhabiting a wide range of depths. These sharks are characterized by their slender bodies, pointed snouts, and two dorsal fins with spines. While they play an important role in marine ecosystems, some species are targeted by fisheries for their meat and liver oil.
Common Names
Members of the genus Squalus are commonly referred to as "dogfish" or "spiny dogfish". This name is shared with other shark species, but it specifically refers to sharks in the genus Squalus.
Characteristics
Squalus sharks typically exhibit the following characteristics:
- Slender, fusiform body shape
- Pointed snout
- Two dorsal fins, each with a strong spine
- Small, widely-spaced eyes
- Five gill slits
- Two anal fins
- Rough skin covered in dermal denticles
- Coloration varies by species, ranging from grey to brown
Environment
Squalus species are found in all oceans around the world, inhabiting a wide range of depths from the surface to over 2,000 meters. They prefer cooler water temperatures and are often found on the continental shelf and slopes. Some species may also venture into deeper waters, particularly during the breeding season.
Diet and Predators
Squalus sharks are carnivorous, feeding primarily on a variety of fish, cephalopods, and crustaceans. They are opportunistic predators, hunting both actively and passively. Their diet varies depending on their size, age, and the availability of prey. Squalus sharks are preyed upon by larger sharks, such as great white sharks and blue sharks, as well as marine mammals, such as seals and dolphins.
Reproduction
Squalus sharks are oviparous, meaning they lay eggs. The eggs are encased in tough, leathery capsules with tendrils that attach them to seaweed or other objects on the seabed. The incubation period varies depending on the species and water temperature. The young sharks emerge from the eggs fully formed and independent.