Reaction of silver eels to artificial light sources and water currents: An experimental deflection study

Flume experiments demonstrated a strong avoidance reaction among silver eels (Anguilla anguilla) to light. In the experimental flume, 65% of eels could be deflected with a fluorescent lamp at an illumination level of about 3–5 mLux. Silver eels preferred a swimming route using the highest water velocity (25 cm s−1). In the dark, significantly more silver eels (75%) chose the compartment with the highest water velocity when given a choice between different water velocities. In a situation with differences in both illumination level and water velocity, the deflection by light was stronger than the attraction caused by the higher water velocity, although the rate of deflection caused by light was slightly influenced by water velocity. These results encourage the development of light-induced deflection systems at (hydro)power stations in order to lower mortality of eels. Copyright © 1999 John Wiley & Sons, Ltd.