The Effectiveness of Light to Guide or Deter Eels

This presentation reviews the world’s literature to describe experiments that evaluate light effectiveness in deterring eels between 2007 and 2015. Bowen (2014) tested a white broad-spectrum LED strobe light in the River Test (UK) and found significant silver eel guidance but interpretation was limited by small sample size. Kruitwagen (2014) worked in the IJmuiden Lock complex (Netherlands): LED strobe lights that emitted white broad-spectrum light considerably reduced eel numbers approaching the trash rack. Bruijs and Vriese (2013) showed that LED strobe lights can fail to guide silver eels. In the River Meuse (Netherlands) the same LED strobe lights used at IJmuiden Lock were placed too close to the bypass inlet and 0.0% guidance was observed. Bruijs and Vriese concluded that turbulence immediately in front of the intake masked the bypass inlet and that turbidity may have also contributed to the array’s failure. These studies showed that LED strobe lights can be effective in guiding silver, outmigrating eels. However, the exact placement of the lights, bypass location and the deployment configuration can defeat an eel guidance structure’s effectiveness. In addition to this review, a proposed light guidance system for outmigrating silver eels in the St. Lawrence River, NY, is described.