In Memoriam -- Prof.Dr. Tufan Koray The marine science and plankton community lost an advocate and a tireless member with the sudden passing away of Professor Tufan Koray on March 9, 2019. He used to describe himself as an idealist and optimist. Prof.Dr. Tufan Koray was an art, music and animal lover. His main areas of work were systematic and taxonomy of marine Protista, phytoplankton ecology, toxic microalgae, and ecological and biological pollution ecometry in fish farms. Born on July 21, 1954, Koray completed his undergraduate studies and graduated in 1977. After his B.Sc. Koray started his M.Sc. studies and graduated in 1982. At the age of 31, he earned his Ph.D. Five years later in 1993, he became a Professor. He became the editor of Ege Journal of Fisheries and Aquatic Sciences in 1992 and continued to work as an editor-in-chief until 2013 successfully and devotedly. In addition to the Biostatistics, Botany, Zoology and Marine Biology started to work on projects related to fisheries in 1993. Prof.Dr. Koray played a major role in the establishment and operation of many projects related with microplankton and toxic algae in Turkey. The Microplanktonic Atlas of the Turkish Seas was his most desired project to complete, and he showed great persistence in this work. Consequently, he and his team successfully accomplished this atlas in 2007. In 2008, he continued to work in a quiet scientific environment before retirement. He retired in January 2016 and moved to Hamburg, Germany. He was interested in nature photography, amateur painting and music in Hamburg. Tufan Koray did not feel well on March 9, and taken to Marien Krankenhaus Hospital by his wife and died on the same day in the evening. Throughout his academic career, he undertook the consultancy of 10 graduate students, 3 of whom were PhD. He had 8 international scientific membershipsi, wrote 4 books, and published 64 national and international research articles. Prof.Dr. Koray has two daughters.