Some biological properties of Kura goby, Ponticola cyrius (Kessler, 1874) (Gobiiformes, Gobiidae) from Kura River, Turkey

This work presents some biological properties, including length-frequency, length-weight relationships, Fulton’s condition factor, growth parameter, and growth performance and mortality indices of Kura goby, Ponticola cyrius . A total of 73 specimens were collected from the Çot Creek a tributary of Kura River, from May to September 2015. Age of P. cyrius varied from 0 to III age with age group I as the most frequent (56.16%). The total length and weight ranged 4.3-16.4 cm, and 1.1050.10 g, respectively. The length-weight relationship was W =0.0145 L 2.9795 with b -value indicating isometric growth pattern . The estimated von Bertalanffy growth parameters are L  = 26.36 cm, k = 0.187 year-1 and t o = -1.33 year. Growth performance index (Φ') and mean Fulton’s condition factor were estimated as 2.115 and 1.43, respectively. Instantaneous rate of total, natural and fishing mortalities were 0.588, 0.371 and 0.217 year-1, respectively and the exploitation rate was calculated as 0.369.