Estimation of growth and mortality parameters and length-weight relationship of Barilius mesopotamicus Berg, 1932 populations in Iran

The aim of the present study was to estimate growth and mortality parameters and length-weight relationship of Barilius mesopotamicus populations in difrent Iran basins. For this purpose, 460 fish specimens from Diala, Jarrahi, Karun, Karkheh and Bushehr basins and subbasins, including Zardmashin, Aalaa, Jarrahi, Dez, Shur, Meymeh, Changooleh, Kangir, Doyrej, Ahram, Zohreh, Kheirabad, Karzin, Shahpur and Darolmizan rivers, were sampled. Total length, fork length and standard length were measured by a digital caliper (cm) and total weight by a digital scale (g). Also, some scales were prepared and studied for age determination. The length-weight relationships showed that population from Bushehr, Jarahi, Karun and Dila, had negative allomeric growth pattern while Karkheh population had an isometric growth pattern. The highest estimated total length and weight was 9.2 cm and 5.4 g. Age of the fish was between 0+ and 2+. The highest asumptetic total length was observed in Diala basin with Bertallanfy equation of Lt= 9.22[1-e-1.3(t+0.07)]. The condition factor was about 0.5. Considering body indices, Bushehr, Jarahi, Karun and Diala had a better condition, and Karkheh population had a lower index, probably indicating a poorer condition in this river.