Age and growth of Capoeta erhani (Actinopterygii: Cypriniformes: Cyprinidae) from the Menzelet Reservoir, Turkey

Abstract

Background. Capoeta erhani Turan, Kottelat et Ekmekçi, 2008 has an economic importance in commercial and recreational fisheries in Turkey. Knowledge of the biology of this species is very scarce. Despite the importance of this species, no research on the population dynamics such as age and growth rates has been conducted. The aim of this study was to determine the age, growth rate, and the relations between the fish size and the otolith size for C. erhani from the Menzelet Reservoir, Turkey. Materials and methods. This study was carried out seasonally in the Menzelet Reservoir, between January and December 2012. Samples were collected using gill nets with mesh sizes ranging from 18 to 30 mm. Results. A total of 134 otoliths obtained from Capoeta erhani that ranged from 15 to 33.8 cm TL were used in the analyses. The overall male : female ratio (M : F = 1.25 : 1.00) was biased in favour of males. The Mann–Whitney test revealed significant differences between sexes, regarding TL (P < 0.05). The calculated length–weight relations were TL = 0.0097W3.0015 (r2 = 0.986) for females, TL = 0.0054W3.2011 (r2 = 0.975) for males, and TL = 0.0075W3.0892 (r2 = 0.979) for all specimens combined. The von Bertalanffy growth models were L∞ = 33.83 cm (TL), K = 0.964, t0 = –0.573 for females; L∞ = 32.02 cm (TL), K = 0.843, t0 = –0.562 for males; L∞ = 33.85 cm (TL), K = 0.821, t0 = –0.482 for all specimens. Conclusion. This study provides the first information on age, growth, and otolith morphometric parameters of Capoeta erhani. Determining the parameters of C. erhani age and growth rates will lead to the estimates of relevant parameters of population dynamics and to better understanding of the long-term changes of the stock sizes.