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

Gordon Copp

doi:10.3391/ai.2007.2.2.5

Abstract

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.

Highlights

The escape or release of non-native fishes into rivers, or still waters connected to water courses, is of increasing concern (e.g. Copp et al 1993, Hickley and Chare 2002, Copp et al 2006), in particular those species for which little or no local data exists on the environmental biology and potential impacts
Most of the non-native fish species introduced to Great Britain have received little scientific study, and especially those of angling interest
There are relatively few published studies of wild populations in Great Britain of common carp Cyprinus carpio (i.e. Linfield 1982, Tenner 1996, Williams et al 2002) and rainbow trout Oncorhynchus mykiss (i.e. Worthington 1940, Lucas 1993), which were introduced to England in about 1496 and in 1884, respectively (Lever 1977)

Summary

Introduction

The escape or release of non-native fishes into rivers, or still waters connected to water courses, is of increasing concern (e.g. Copp et al 1993, Hickley and Chare 2002, Copp et al 2006), in particular those species for which little or no local data exists on the environmental biology and potential impacts. Copp et al 1993, Hickley and Chare 2002, Copp et al 2006), in particular those species for which little or no local data exists on the environmental biology and potential impacts. Most of the non-native fish species introduced to Great Britain have received little scientific study, and especially those of angling interest. Worthington 1940, Lucas 1993), which were introduced to England in about 1496 and in 1884, respectively (Lever 1977). European (wels) catfish Silurus glanis, which was introduced to England in 1853 (Lever 1977) and is a popular sport fish (Hickley and Chare 2002), has received no scientific study of any kind in the UK.

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