Explicit site fidelity of European catfish ( Silurus glanis, L., 1758) to man- made habitat in the River Meuse, Netherlands

After a century of near absence, records of European catfish (Silurus glanis, L., 1758) in the Netherlands have increased markedly since 1994. The majority of records (about 60% of the total) originate from a 12km dammed section of the River Meuse in the province of Limburg. This paper reports on a study conducted to obtain information on the behaviour and habitat preferences of catfish at this location, whereby 20 adult Silurus glanis were implanted with both acoustic and transponder tags and their behavior monitored using a combination of passive and active methodologies. All fish remained within the study area and did not enter either the contiguous riverine sections or connected lakes. The catfish expressed schooling, nocturnal activity and strong site fidelity to a specific river section containing artificial habitat (in the form of moored boats) and were influenced by the presence and operation of nearby energy generation plants. The results are discussed in relation to the potential growth and dispersal of catfish populations and the extent to which anthropogenic activities (particularly energy generation schemes) at the site have inadvertently created favourable habitat that has assisted the colonization of catfish and impacted negatively on the wider fish community.