Description and characteristics
The spiny dogfish (Squalus acanthias) is a small shark with an elongated, fusiform body, grey-brown with white spots on the flanks. It has two dorsal fins, each with a venom-carrying spine.
Habitat and distribution
It lives in the salt waters of the Black Sea, occasionally found in deeper waters near the Danube Delta. It prefers sandy bottoms and moderate temperatures.
Diet and behaviour
It feeds on schooling fish, cephalopods and crustaceans, being an active predator. It lives in schools and is seasonally migratory.
Reproduction
It is a viviparous species, with females giving birth to live young after a long gestation. The young are independent at birth. Late sexual maturity and slow reproductive cycle.
Economic and ecological importance
It has local fishing value, used for flesh and fins. Ecologically, it occupies a higher trophic level, controlling schooling-fish populations.
Threats and conservation
It is vulnerable due to slow growth and late reproduction, affected by overfishing. It is classified as a vulnerable species globally.
Fishing and legal minimum size
It is caught accidentally or in bottom fishing. In the table of minimum legal sizes, the spiny dogfish (Squalus acanthias) has a minimum legal size of 120 cm.
Conclusion
The spiny dogfish is a vulnerable cartilaginous fish, important for the balance of marine ecosystems near the Danube Delta.