Age structure, growth rate and condition of Barbus cyclolepis (Cyprinidae) from the middle zone of the Maritsa river

Abstract

This paper examines the age, growth and condition factors of Barbus cyclolepis from the middle reaches of the Maritsa River. The material contains 486 specimens collected in the river section from the town of Kostenets to the village of Zlokuchene. The aim of this study is to establish the population parameters of the Maritsa barbel from the middle zone of the Maritsa River. Seven age groups are established. One-year-old fish predominate the sample. The most numerous are fish of 81 to 110 mm length. Linear growth of Maritsa barbel from the middle course of the Maritsa River is similar to that of the same species from the lower course of the river in the vicinity of the city of Plovdiv. In comparison, Maritsa barbel from the more southerly flowing Arda River and from the Dospat Dam has greater linear growth. A comparison of same-length fish from different rivers reveals that the barbel reaches a larger mass in the Arda River and in a stretch of the Maritsa River in the vicinity of the city of Plovdiv. This observation may be due to the lower altitude, warmer climate and longer growing season in this part of the Maritsa River basin.