6th Annual Judith Ramaley Celebration of Research and Creative Scholarship
 
Online Book of Abtracts

Poster #117

Trophic Patterns of Fish across Patch Types of a Large Floodplain River

Travis J. Viker

Faculty Mentor: Michael D. Delong

A floodplain river is a mosaic of patch types with discrete hydrogeomorphic conditions that shape their ecological character. Identifying trophic patterns of fish will help in understanding how food web organization is influenced by patch character. The objective of this study was to examine differences in food web attributes of different habitats using stable isotopes. Fish were collected from the Upper Mississippi River, between RK 1162-1175 in August and September of 2011. Three different patch types (main channel, secondary channel, and backwater) were sampled to provide larger-scale representation of the river mosaic. Fish were collected via electrofishing. Fish were identified to species and a tissue sample was taken before the fish were returned to the water. Gut contents were also collected for representative Piscivores.  Stable isotopic analysis was completed at the Stable Isotope Mass Spectrometry Lab, Kansas State University.  Bi-plot analysis indicated that isotopic ratios of most fish differed between the three habitats, suggesting that feeding was primarily local.  This included both piscivorous and invertivorous species, which are often thought to use multiple feeding patches.  A clear exception to this was Esox lucius from secondary channels, where variation in d¹⁵N was high, indicating a variable diet.  Habitat-specific differences will be examined further by determining the trophic position of fish to determine food chain length and location of fish on the food chain.​