Walter R. Courtenay Jr., of Gainesville, Florida, died Jan. 30 at age 80. He was a leading authority on invasive nonindigenous fish, particularly those introduced into the United States. He did much to increase public awareness of how species important in the ornamental and aquaculture industries can be extraordinarily destructive to native environments. His knowledge of the destructive sharp-toothed Asian fish known as the northern snakehead earned him the nickname “Mr. Snakehead,” and he was admired for his vast collection of fish-themed shirts.
Courtenay taught at Duke University, Boston University, and from 1967 to 1999 at Florida Atlantic University at Boca Raton, where he twice chaired the Department of Biological Sciences. At various times he also held research appointments with the U.S. Bureau of Commercial Fisheries, the Museum of Comparative Zoology at Harvard, the U.S. Fish and Wildlife Service, and at Arizona State University. After retirement he relocated to Gainesville, where he continued his research alongside colleagues at the University of Florida. In 2000 he was made fellow, emeritus, of the American Institute of Fishery Research Biologists.
In his final years Courtenay was a courtesy curator for the Florida Museum of Natural History and a research fishery biologist with the U.S. Geological Survey, Biological Resources Division, at the Florida Integrated Science Center in Gainesville. He is survived by his brother, two children, stepmother, a granddaughter and his children’s mother.