Büyük zap nehrinde (İrak) yaşayan arabibarbus grypus (heckel, 1843) (sabut) popülasyonunun bazi büyüme özelliklerinin belirlenmesi

The present study aims at examination of important growth traits and age structure of A. grypus (shabut) living in the Great Zab River, northern Iraq. Being a native cyprinid and species of great ecological and commercial importance in the Tigris- Euphrates basin, study of its growth dynamics is important in sustainable management of fisheries. Fish samples were monthly taken between September 2024 and February 2025 and biometric data including total length, weight, sex and age were subjected to standard fisheries science tools including length-weight relationships, condition factor (CF), and the von Bertalanffy Growth Function (VBGF). The age structure of the population was wide (I-XIII) indicating a stable low-exploitation environment showing constant recruitment. The length-weight relationship showed a close correlation (R 2 =0.97-0.98) with negative allometric growth (b < 3), meaning that the individuals increase more in length than in mass. The analysis of condition factors revealed that CF values were higher in females than males, with the peak at age IV, which was probably caused by reproductive investment. Slow somatic growth (k = 0.05) and long longevity that were also confirmed by VBGF parameters are characteristics of ecologically balanced habitat.