Carl Walters

Other modeling equations like the Beverton-Holt model and the "hockey stick" model by Barrowman and Myers (2000) try to explain density dependent effects of juvenile fish populations using processes like recruitment and the number of eggs produced. Fisheries biologists and population ecologists have used the Beverton-Holt model since the 1960s to describe the "stock-recruitment" relationship. However, Walters believed that juvenile behavior could also explain the density dependent relationship that Beverton and Holt and Barrowman and Myers described. Walters thought that juvenile behavior, in conjunction with habitat, could explain the density dependency seen when foraging for prey and avoiding predators. Walters wanted to give scientists a better understanding of the processes that drive density dependent fluctuations in ecosystem statistics (birth and death rates). The foraging arena theory is also used, in conjunction with the ecosystem simulation program Ecopath with Ecosim, to account for the indirect effects and trophic cascades seen in populations.

Walters's first professorship was at the University of British Columbia as an Assistant Professor in the UBC Institute for Animal Resource Ecology. In 1977, he became an Associate Professor and then a Professor in 1982. Prior to his professional appointment at UBC, Walters worked for the California Department of Fish and Game and was also a graduate fellow, a consultant, and an aide on numerous occasions. He has taken sabbaticals to the International Institute of Applied Systems Analysis in Vienna, the University of Florida, where he is an adjunct professor, and Australia. He has been on the editorial board for multiple journals including the Canadian Journal of Fisheries and Aquatic Sciences, Conservation Ecology, and Ecosystems and has been the associate editor of the Journal of Applied Mathematics and Computation and the Northwest Environmental Journal. He was the editor of the Open Fish Science Journal. Walters also served, and continues to serve, as a consultant to many government agencies.

Carl Walters graduated from Bakersfield College with an A.A in 1963 and continued to Humboldt State College to graduate with a B.S. in 1965. After Walters graduated, he went to Colorado State University to study the "Distribution and production of midges in an alpine lake" under the advisement of Dr. Robert E. Vincent. After obtaining his M.S. in 1967, Walters stayed on with R.E. Vincent to get his doctorate on the "Effects of fish introduction on invertebrate fauna of an alpine lake" and graduated in 1969. Walters did not go on for a postdoctoral position; instead he almost immediately started working at the University of British Columbia in Vancouver, British Columbia, Canada.

Carl Walters (born 1944) is an American-born Canadian biologist known for his work involving fisheries stock assessments, the adaptive management concept, and ecosystem modeling. Walters has been a professor of Zoology and Fisheries at the University of British Columbia since 1969. He is one of the main developers of the ecological modelling software Ecopath. His most recent work focuses on how to adjust human behaviors in environments that are full of uncertainty. He is a recent recipient of the Volvo Environment Prize (2006). In 2019, Dr. Walters became a Member of the Order of British Columbia.