The Tarek (Alburnus tarichi, Guldenstaedt 1814) is an endemic fish species for the Van Lake Basin, which migrates for reproductive. Karasu is the most important rivers in the Van Lake Basin where tarek migrates. However, many sand pits and sand extraction activities on Karasu are an important environmental problem during the breeding period of tarek. In this study, stress effects on tarek were analyzed in order to determine the effects of sand pits and sand extraction activities in Karasu Stream. The blood samples were taken from a total of 84 tarek, 55 females and 29 males in Karasu stream (Ablanges, Teave, Topaktas and Zeve sampling locations, respectively) during the breeding period. Cortisol and glucose levels were measured to determine stress levels in blood samples. The levels of cortisol were 50.96±2.68, 34.49±3.72, 27.97±4.05 and 45.69±3.61 μg dL-1, while glucose levels were determined as 278.95±18.36, 212.64±12.47, 235.15±16.93 and 235.09±14.29 mg dL-1, respectively. The average levels of cortisol and glucose in female and male tarek were 39.65±2.55 and 40.06±3.26
μg dL-1, 240.87±9.95 and 237.38±13.89 mg dL-1, respectively. Total suspended solid (TSS) levels at the sampling points were 123.1, 135.0, 90.5 and 63.5 mg L-1, while turbidity was measured as 104.5, 102.5, 71.2 and 37.1 NTU respectively. The analyzes shows that, the stress on tarek was determined as high level in TSS and turbidity due to sand pits and sand extraction activities. The stopping of these activities during the breeding period of the tarek is important to ensure continuity.