Life history of spiny dogfish, Squalus acanthias (L. 1758), in the southern Black Sea

Age, growth parameters and food of Squalus acanthias L., spiny dogfish sampled from the SE Black Sea were studied. First and second dorsal spines were used for ageing. Spiny dogfish from age classes 1 to 38 were identified with an age distribution of 2–38 years for females and 1–27 for males. The length–weight relationship was W = 0.0000004 × L 3.5 and W = 0.0000008 × L 3.32 for females and males, respectively. The estimated von Bertalanffy growth parameters were; L ∞ = 137.73 (±1.22) cm, K = 0.1263 (±0.0073) (year −1), t 0 = 1.67 (±0.25) (year) ( r 2 = 0.93) for females, L ∞ = 123.78 (±4.85) cm, K = 0.168 (±0.024) (year −1), t 0 = 2.62 (year) ( r 2 = 0.96) for males and L ∞ = 136.76 (±1.42) cm, K = 0.133 (±0.006) (year −1), t 0 = 2.15 (±0.178) (year) ( r 2 = 0.95) for sexes combined. They feed mainly on fish (IRI% = 97.63) and crustaceans (IRI% = 2.23). Whiting was the main prey item in all seasons (IRI% = 87.81) except for winter where they feed mainly on anchovy (IRI% = 96.46). The stomach fullness and dietary component were affected by the gear used as well as seasons. It was concluded that the abundance and availability of the prey are main factors for the spiny dogfish feeding strategy in the Black Sea.