Author(s)

G. Kruitwagen

Abstract

Every year large numbers of silver eels (Anguilla anguilla) approach the IJmuiden Lock Complex on their spawning migration to sea. The IJmuiden Lock Complex provides various passage routes. The Dutch Ministry of Works and Infrastructure commissioned research to assess the significance of the mortality of silver eels in the IJmuiden pumping station. The effectiveness of strobe lights and reduction of flow rate to reduce silver eel mortality was investigated using a DIDSON camera and nets. The research programme provided a unique insight in the effectiveness of behaviour-based fish guidance measures. It was found that silver eel damage and mortality at the pumping station was about 4% of the total number of silver eels that arrive at the lock complex. The use of strobe light resulted in a strong reduction in the number of silver eels that were observed approaching the trash rack and the pumping station. Reduction of the flow rate from 50 to 25 m3/s also resulted in a reduction of silver eel passage through the pumps. The reduction in flow rate also resulted in a significant reduction of damage to the passing eels. Both the strobe lights and the reduction of flow rate (pump management) provide effective solutions that enhance the natural reluctance of silver eels to pass through pumping stations and guide them to alternative passage routes. Keywords: fish passage, eel, Anguilla anguilla, pumping station, lock, fish guidance, pump management, strobe lights.

Keywords

fish passage, eel, Anguilla anguilla, pumping station, lock, fish guidance, pump management, strobe lights.