T.K. (Kieran) McCarthy (1949-2019) graduated from University College Cork, with a first-class honours’ degree in zoology in 1971 and a PhD on the Irish freshwater Hirudinea (leeches) in 1974. Following post-doctoral research in Oxford, Finland, and Dublin, he was appointed to the Zoology Department, N.U.I., Galway. Throughout his career, and after retirement in 2011, he continued his research on a variety of aspects of freshwater ecology (limnology, entomology, fish parasitology and biogeography) and especially on European eels. He was a Visiting Professor at the University of Łodz, Poland, and University of Tokyo, Japan.