Is European catfish Silurus glanis really becoming more abundant in the River Thames?

An increased number of reports (by anglers, in the angling press) of European (wels) catfish Silurus glanis occurrences in the River Thames (England) has led to the perception that the species has become more abundant in that river. If proved true, then this would have ramifications for non-native species policy and practice. To assess catfish density, a total of 256 rod hours of specialized angling (‘clonking’) was undertaken during both day and night between 17 and 21 July 2006 at numerous sites within six sectors of the River Thames. No European catfish were captured, which suggests that European catfish remains a rare species in the River Thames, providing no corroboration of anecdotal reports of increased abundance.