Hasler at the Limnology Garden in Madison. (Courtesy of Fritz Hasler.)

Professor Hasler examines a Micropteen Salmoides, caught by a colleague in Lake Mendota, August 1948. (Image courtesy of the UW Archives, #S09096.)

As graduate students, Hasler (right) and Hugo Baum build lime floats at Trout Lake Research Station, 1933. (Image courtesy of the Wisconsin Historical Society, #27176.)

Jim Kitchell, in plaid, and John Magnuson to Arthur Hasler's left. (Courtesy of the UW Center for Limnology.)

A Fresh Perspective on Limnology

A pioneer in the study of freshwater ecology, Arthur Hasler PhD1937 carried on the University of Wisconsin traditions of curiosity and conservation for four decades, discovering new ways to conduct research and pushing to protect our natural resources.

A key figure in advancing the study of limnology at the university, Hasler offered a fresh perspective that influenced how we study aquatic ecosystems, pollution control, and wildlife management around the world.

Hasler arrived in Madison in 1932 to study under Chancey Juday, a pioneer of lake science research along with E.A. Birge. Hasler took a few sabbaticals after earning his Ph.D in zoology in 1937, serving as an analyst with the Air Force Strategic Bombing Survey in Germany in 1945, and returning a decade later as a Fulbright Research Scholar.

He was promoted to full professor of zoology in 1948 and worked at the UW for 41 years, turning the university into a world-renowned hub for aquatic research.

Diverging from the beliefs of predecessors Birge and Juday, Hasler hypothesized that freshwater ecosystems are heavily influenced by their surroundings, from plants to pollution, known as cultural eutrophication. His studies informed widespread efforts to curb soil erosion and contamination by sewage and fertilizer.

In one famous experiment, Hasler introduced a better way to study aquatic ecosystems by building a barrier between Michigan’s Peter and Paul lakes, creating control and test environments in which to study aquatic life. This method is used today to study acid rain, pollution, and invasion by exotic species.

Hasler is best known for his findings on how salmon spawn. While hiking near his childhood home in Utah, he was struck by the way familiar smells trigger memories, and wondered if salmon were similarly compelled to spawn where they were born — a concept known as olfactory imprinting. His discovery influenced salmon management strategies around the world.

In 1958, the National Science Foundation granted Hasler funds to build a working research station on Lake Mendota. The Laboratory of Limnology opened in 1963 and was renamed the Hasler Laboratory of Limnology in 2005.

After retiring in 1978, Hasler served as an emeritus professor of limnology and maintained close ties to the university until his death in 2001.