6th Annual Judith Ramaley Celebration of Research and Creative Scholarship
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Poster #11 Chemical and Physical Water Properties and Their Effect on Fish Assemblages in Southeastern Minnesota Streams Brian J. Beyerl Faculty Mentor: Michael D. Delong Southeastern Minnesota contains a large number of streams of varying thermal classifications including cold-, cool-, and warm-water. This part of the state has been changed by anthropomorphic influences on the landscape that began with European settlement that has led to degradation of water quality. Twelve streams within the Whitewater and Root River drainages were sampled for water chemistry and fish community composition in 2008 and 2010. The objective of this study was to identify physical-chemical characteristics, either short- or longer-term that shape community structure in two geomorphologically distinct drainages. Fish were collected during the summer months. Samples for determination of water chemistry (total nitrogen, total phosphorus, total suspended solids, and turbidity) were collected spring through fall. Water temperature, turbidity, and discharge were recorded every 10 or 15 minutes throughout the summer using pressure transducers and DTS-12s connected to data loggers. Continuous data was for turbidity, discharge, and temperature was used to generate daily averages which were then used to create variables to reflect environmental conditions for periods of 2- and 4-months prior to collection of fish samples. In total, 64 species were represented by 8,247 individuals across all sites. White suckers (Castostomus commersonii) dominated the findings representing 29.7% of the total individuals, followed by Brown trout (Salmo trutta) at 20%. The Best procedure of Primer identified dissolved oxygen concentration, 2-month maximum total nitrogen, 2-month maximum temperature, 2-month minimum discharge, and 4-month average temperature as important determinants of community structure ( ρ = 0.838). The findings demonstrate that longer-term measures of environmental condition have a greater influence on fish community structure than measurements taken at the time of sampling. This suggests that community organization in these streams have maximum or minimum thresholds of the presence of species and highlight the need for long-term data monitoring. |
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