Abstract St. Petersburg State University announces with deep regret the unexpected and tragic death, on July 16, 2015, of Dr Yuriy K. Kuznetsov, a member of the Department of Ichthyology and Hydrobiology. He was a talented teacher and an inquisitive researcher, an erudite in many fields of ichthyology and general biology.Yuriy Kuznetsov was deeply devoted to science and very delicate person devoid of any ambition. Without exaggeration, for many of us, he was the absolute authority in the discipline. In his later years, while working in the Laboratory of Experimental Ichthyology he published a number of important publications, co-authored two books and, on the eve of the death, completed editing another book. He was a great worker of science, an intelligent and knowledgeable colleague, and a friend always ready to help and support.