Biological properties of Luciobarbus xanthopterus in the Al-Diwaniya River, middle of Iraq

Abstract

Despite the importance of Luciobarbus xanthopterus as one of the most valuable and economic species in Iraq, no research on the biology of this species has been conducted in the Al-Diwaniya river. This study aimed to determine the growth, reproduction and food habit of L. xanthopterus in this river between November 2016 and October 2017. Samples were collected by different fishing gears. The calculated length-weight relationship for fish sizes 12.0 to 60.2 cm was W = 0.008L3.093, with positive allometric growth. The highest value of the relative condition factor was in April and the lowest in May. Seven ages were identified from the scales and the mean lengths of these ages were 15.3, 26.3, 35.9, 42.8, 49.0, 54.7 and 57.1 cm, respectively. von Bertalanffy growth model was Lt= 73 [1-e -0.228 (t-0.012)]. The overall male: female ratio (1:1.57) was biased in favour of females. Length at first maturity was 36 cm for males and 38 cm for females. The GSI of the species was at the highest level in March means that spawning activity is going to start after this month. There were significant correlations between water temperature and both feeding activity and intensity of the fish. The species is omnivorous, fed mainly on aquatic insects, macrophytes, detritus, crustacean, and diatoms. The results obtained can assist in fisheries management and conservation of the species in this river.