ACTA ZOOLOGICA BULGARICA, vol.72, no.3, pp.429-438, 2020 (SCI-Expanded)
Phoxinus strandjae Drensky, 1926 is a cyprinid species distributed from the Veleka River (Bulgaria) to GOnen and Bityfilcsu Streams (Anatolia, Turkey). Because of the lack of biological knowledge on P. strandjae in its natural distribution area, life-history traits and feeding of this species were studied. During a 16-month sampling (from March 2012 to June 2013), specimens of P. strancljae were collected from the Istranca Stream in order to study age, growth, reproduction and diet composition of the species. The maximum age recorded was 6+. The length-weight relationships proved a positive allometric growth in females and an isometric growth in males, or /nW=-3.883+3.075/nSL and /nW=-3.857+3.044/nSL, respectively. The average length at first maturity of female was 2.99 cm, while in the male it was 2.89 cm. The mean absolute fecundity in the mature females was 839 eggs (ranged from 101 to 2392 eggs). Insects (93.16%) were the most prevalent food item in terms of the modified index of relative importance (MI%) and the consumed insect groups mostly composed of Diptera (IRI%=88.90).