Donald Strathearn Rawson (1905–1961)
Donald Strathearn Rawson was a pioneering professional limnologist in western Canada in the first half of the 20th century. He conducted scientific studies of inland aquatic ecosystems, including the first extensive studies of the large lakes of the northwest, including Great Slave Lake and Lake Athabasca. His limnological research on Great Slave Lake led to its classification as a body of water of comparable production to the upper Great Lakes, and to the establishment of a lucrative commercial fishery there in 1945. Through his research, principally his holistic limnological chart titled “Trophic Nature of the Lake,” Rawson helped scientists understand the interrelated factors that determine a lake’s productivity levels (the amount of algae, aquatic plants, and animal life that a lake can support). This led to the development by others of the “morphoedaphic index” (MEI), a widely used tool providing limnologists with a means of predicting a lake’s productivity that balances the effects of shape and mineral content of the lake’s basin.
Rawson was born near Uxbridge, Ontario, and educated in biology at the University of Toronto, where he specialized in the emerging field of limnology. In 1928, he joined the biology department at the University of Saskatchewan, which he led as department chair from 1949 to 1961. Saskatchewan’s Fisheries Branch sponsored Rawson’s work for more than a decade, establishing a Fisheries Laboratory at the University of Saskatchewan’s Department of Biology, with Rawson at its head from 1948 to 1960. Rawson operated in the nexus between limnology, conservation, and the study and management of fisheries, writing scientific reports that also detailed the potential productivity of lakes for commercial fisheries. As an early Canadian limnologist, Rawson contributed to the growth of this relatively new scientific field, advancing Canadian science at the national and international levels.
Between 1928 and 1935, he conducted pioneering studies on lakes and fisheries in Prince Albert National Park (Saskatchewan) and Riding Mountain National Park (Manitoba). He adopted a novel and holistic (all-inclusive, universal) approach to limnological studies of lakes, involving an interdependence of factors such as human impact, edaphic conditions (soil factors and how they affect living organisms), the shape of a lake’s basin, and climate, leading to a better understanding of lake productivity and fisheries potential.
In recognition of his contributions to scientific research and conservation, Rawson was elected a Fellow of the Royal Society of Canada (1944) and made a member of the Fisheries Research Board of Canada (1959-61). He also served on the Royal Commission on the Fisheries of Saskatchewan (1946-47), was president of the Canadian Committee for Freshwater Fisheries Research (1951), and the Limnological Society of America (1947), the international limnological organization. In addition, he helped found the Canadian Society of Wildlife and Fishery Biologists in 1958 (now known as the Canadian Society of Environmental Biologists), an organization dedicated to research and conservation of natural resources.