Retention of T-bar anchor and dart tags by a wild population of African sharptooth catfish, Clarias gariepinus

A double-tagging experiment is presented that estimates tag retention by plastic dart and T-bar anchor tags in a wild population of Clarias gariepinus. It is shown that plastic dart tags are the most suitable tag as there was 100% initial retention and long-term loss of 2% per annum. T-bar anchor tags had an initial tag retention rate of 81% and no measurable long-term loss. A combination of tag design is attributed to the poor performance of T-bar anchor tags as the T-piece of the tag does not properly anchor behind the pterygiophores.