Dr Tomoyoshi Yoshinaga is a professor of the Department of Aquatic Bioscience at the Graduate School of Agricultural and Life Sciences, the University of Tokyo. After receiving his PhD degree from that university in 1987, he entered the Ministry of Agriculture, Forestry and Fisheries as a researcher, where he worked at the National Research Institute of Fisheries Science and the National Research Institute of Aquaculture. He returned to the University of Tokyo in 2002 as a professor after his fifteen-year career at the ministry. Dr Yoshinaga is still a member of several committees on fish health and animal drugs in the ministry. He has been serving as the president of the Japanese Society of Fish Pathology since 1 April 2019. He has studied mainly fish and shellfish parasites and, for the last ten years, has expanded his interest and activity in the field of biosecurity of aquatic animals.