Inland migration study of sea trout (Salmo trutta) into the rivers Rhine and Meuse (The Netherlands), based on inductive coupling radio telemetry

Abstract

A new telemetric method, the NEDAP TRAIL System®, has been developed to study sea trout migration in the delta area of the rivers Rhine and Meuse. This method is based on inductive coupling between an antenna loop on the bottom of a river or canal and ferrite rod antenna incorporated in a tag of the transponder type. Field tests showed that the detection system functions well with an maximum antenna length of a least 550 m, a water depth of 15 m and a passing speed of the tag with 5-6 m s-1 at maximum. A first group of 18 sea trout (of the total number of 600 that will be tagged) was tagged in December 1996. By March 1997 two of them had already been detected at different detection stations.