The Daily Bulletin Archive

The Great Lakes Center and the Biology Department invite you to join us for the seminar "The Maumee River: A Fish-Eye View," presented by Christine Mayer, professor of ecology at the University of Toledo, today, October 17, from 4:30 to 5:45 p.m. in Bulger Communication Center West 2. All students, staff, and faculty are welcome.

Seminar Abstract
Tributaries to large lakes provide important spawning and nursery habitats for many species of migratory fish. The presence of spawning stocks in multiple tributaries and other locations adds stability to the lake-wide populations of fish. The Maumee is the largest tributary into Lake Erie and hosts many migratory fish species, including walleye. Approximately a half-million adult walleye enter the Maumee River annually to spawn, and 11 million to 85 million larval walleye exit the mouth of the river. Many other species also spawn in the Maumee, and the diversity of the larval assemblage has increased since the 1970s, suggesting that water quality or other conditions have improved; however, there are impediments to some fish species using spawning habitat in the river. Surveys of relative abundance of walleye eggs in 2014 and 2015 showed that egg density declined about 30 km from the river mouth, even though there is high-quality habitat upstream. There may be a velocity barrier at this location that prevents walleye from swimming farther upstream, possibly causing habitat limitation for spawning. Unlike walleye, which are still numerous, lake sturgeon are now extirpated from the Maumee River and Western Basin, even though they were once highly abundant. A habitat-suitability model has shown that there is still relatively abundant appropriate habitat in the river, despite the lack of spawning by this species for over 100 years. In summer 2017, a rearing facility for lake sturgeon will be constructed at the Toledo Zoo, and juvenile sturgeon will be released in 2018. The value of spawning habitat in the Maumee River will be enhanced by reintroducing native sturgeon and could be further improved by restoration that reduced high-flow conditions, which may limit access by slower-swimming fish such as walleye.