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Please use this identifier to cite or link to this item: http://hdl.handle.net/1974/984

Title: The Role of Invasive Bythotrephes longimanus in Lake Food Webs
Authors: Hatton, Elizabeth Courtney

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Keywords: Bythotrephes
stable isotope analysis
Issue Date: 2008
Series/Report no.: Canadian theses
Abstract: Bythotrephes longimanus, a predatory exotic cladoceran, has spread rapidly to numerous lakes through the Laurentian Great Lakes region of Ontario and North America. Post-invaded lakes are known to have reduced zooplankton species richness, biomass and altered community structure. Bythotrephes may also affect the diet and trophic position of macroinvertebrate predators and prey species for fish (e.g., Mysis relicta). However, the effects of this species in altering higher trophic levels remain largely unexamined. Using a combined approach of stable isotope (d13C and d15N) and THg analysis, the trophic position of Bythotrephes in two invaded lakes was investigated. Based on d15N values, Bythotrephes shared a similar trophic position to native macroinvertebrate predators (9 and 7‰ for Peninsula and Harp lakes, respectively). Using a mixing model and stomach content analysis we show that, despite low and patchy lake abundance, Bythotrephes may be a key prey item to fish and has approximate dietary contributions similar to native prey items, such as zooplankton, Chaoborus and Mysis. In both lakes, Hg conformed to predicted biomagnification trends as indicated by 15N. When Bythotrephes invades lakes with native macroinvertebrate predators, it inserts itself into the same trophic position and does not have major effects on food web length.
Description: Thesis (Master, Biology) -- Queen's University, 2008-01-10 22:00:22.188
URI: http://hdl.handle.net/1974/984
Appears in Collections:Department of Biology Graduate Theses
Queen's Graduate Theses and Dissertations

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