A study on some biological parameters of the population of Chondrostoma angorense Elvira, 1987 (Actinopterygii: Cypriniformes: Leuciscidae) in the Devrez River, Türkiye

Understanding the biological characteristics of fishes is essential for conserving native, particularly endemic species and providing accurate recommendations for fisheries management. In Türkiye, studies on the endemic Ankara nase, Chondrostoma angorense, are rare, and no data are available on its reproductive biology. This study provides some biological parameters of C. angorense, including population age structure, growth, and reproductive characteristics, from the Devrez River. Fish specimens were sampled monthly from April 2020 to March 2021 using a cast net. The overall ratio of males to females was 0.98:1, with an age distribution of I–V age groups. The length–weight relationship and von Bertalanffy growth function were estimated as log W = −1.9586 + 3.0039 log (L) and L_t = 32.64 (1 − e^{−0.109 (t + 1.870)}), respectively. The maturity ogives indicated that 50% of males and females reached sexual maturity at total lengths (TLs) of 14 cm and 16 cm and weights of 25 g and 34 g, respectively. C. angorense had a protracted spawning season lasting from March to June. The absolute fecundity ranged from 1015 to 10 664 oocytes, with an average of 5130. Fecundity was positively correlated with fork length, total weight, gonad weight, and age.