Laboratory studies of fish entrainment sampling using a screw centrifugal impeller pump.

This article focuses on evaluating the mortality of entrainable fish eggs and larvae caused by passage through a screw-type centrifugal pump, specifically the Hidrostal pump, used for entrainment sampling at industrial water intakes. Laboratory tests with Lake Trout (Salvelinus namaycush) eggs and larvae, Lake Whitefish (Coregonus clupeaformis) eggs, and juvenile Rainbow Trout (Oncorhynchus mykiss) at flow rates of 39.5, 47.3, and 59.1 m³/h showed very high survival rates (≥99%) with minimal mortality attributable to the pump. These findings suggest that the Hidrostal pump causes less damage to fish early life stages compared to other sampling methods, thereby reducing error in estimating entrainment losses required by regulatory legislation in the United States and Canada. The study recommends further field testing to confirm the pump's applicability under operational conditions and notes potential limitations such as clogging and hydraulic head constraints.