Effects of planktivorous fish mass mortality on theplankton community of Lake Mendota, Wisconsin
Document Type
Article
Journal/Book Title/Conference
Hydrobiologia
Volume
200
Publication Date
1990
Keywords
planktivorous, mortality, plankton
First Page
329
Last Page
336
Abstract
Massive mortality of planktivorous fish had a dramatic impact on plankton community dynamics of Lake Mendota, Wisconsin, USA. After fish mortality, the largerDaphnia pulicaria replaced the smallerDaphnia galeata mendotae, resulting in greater grazing pressure on phytoplankton. This was accompanied by a much longer spring clear-water period and lower summer phytoplankton biomass compared to years before the fish mortality. Analysis of historical data (from the mid-1970's) showed that previous fluctuations in planktivorous abundance had similar effects onDaphnia abundance and species composition, and on spring phytoplankton biomass. However, the mid-1970's fish fluctuations had no detectable effect on summer phytoplankton. Concentrations of phosphorus were much higher in the 1970's (spring P 80–135 µg 1−1) than in the 1980's (spring P 19–36 µg 1−1) and it is possible that high P concentrations may reduce trophic cascade effects on summer phytoplankton communities. This suggests that the success of biomanipulation programs may be dependent on lake nutrient status.
Recommended Citation
Vanni, M.J., C. Luecke, J.F. Kitchell, and J.J. Magnuson. 1990. Effects of planktivorous fish mass mortality on the plankton community of Lake Mendota, Wisconsin. Hydrobiologia 200/201: 329-336.
