Charles McLean Fraser (1872–1946) is best remembered for his work on hydroids, but he was also involved in a much broader range of activities during the development of marine biology on the Pacific coast of Canada in the first half of the 20th century. He first became interested in hydroids when, as a graduate student at the University of Toronto, he collected from the floating laboratory near Canso, Nova Scotia. In 1903 he began teaching at the high school in Nelson, British Columbia, and collected hydroids at various locations on the Pacific coast. He completed a Ph.D. under the direction of C. C. Nutting at the University of Iowa. Fraser had worked at the Pacific Biological Station in 1908, the first year it was open, and in 1912 he became its second curator. In the latter capacity he was a member of a commission on sea lions, and worked on such commercially important species as salmon and herring. From 1920 to 1940 he was Head of the Department of Zoology at the University of British Columbia and continued marine work there. He was an influential member of societies such as the Royal Society of Canada and the Pacific Science Association. In the decade before the Second World War he also participated in the Allan Hancock Pacific Expeditions which collected from Southern California to Peru and east into the Caribbean Sea. His hydroid work culminated in the publication of three books on hydroids of the Pacific and Atlantic coasts of North America and their distribution and relationships.