Efficacy of tagging European catfish Silurus glanis (L., 1758) released into ponds

The efficacy and sub-lethal consequences of single and double tagging European catfish Silurus glanis with Petersen disc and passive integrated transponder (PIT) tags were examined in short (laboratory) and longer-term (field) experiments. Tag retention in the laboratory was 100%, with normal behaviour (i.e. feeding) in all fish returning within 36 h. In the field, 65 of 120 tagged S. glanis were recaptured from five small study ponds, with 85% retaining their PIT tags, though recapture rates and tagging efficacy were highly variable amongst locations. This is consistent with literature for other fishes, suggesting that tagging efficiency is variable across species and largely context dependent (fish length, tagging location, habitat).