Great Lakes Center Seminar:

"Change in diel catchability of young-of-year yellow perch associated with establishment of dreissenid mussels"

Martin A. Stapanian, Ph.D.
U.S. Geological Survey
Lake Erie Biological Station

Water clarity increased in nearshore areas of western Lake Erie by the early 1990s, following passage of water quality legislation in 1972 and the invasion of dreissenid mussels (Dreissena spp.) beginning in 1987. We hypothesized that increased water clarity in Lake Erie resulted in decreased catchability of young-of-year (age-0) yellow perch (Perca flavescens) during daylight compared to during night. We used a two-tiered modeling approach to test this hypothesis on the ratio (R) of catch per hour (CPH) during night to CPH during daylight in bottom trawl surveys conducted during 1961-2005. The best a priori and a posteriori models had breaks in R between 1990 and 1991, corresponding to 3 years after the dreissenid invasion. The results supported our hypothesis that age-0 yellow perch exhibited a transition to lower catchability during daylight compared to night, and the timing of the transition coincided with the establishment of dreissenid mussels.

Thursday, September 23, 2010
12:15–1:30 p.m.
Classroom Building B118

Students, staff, and faculty are welcome. Light refreshments will be served.