Carbon Sources Supporting Fish Growth in Lake Diefenbaker
Date
2018-05-02
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Thesis
Degree Level
Masters
Abstract
There are two main carbon sources for consumers in aquatic ecosystems: allochthonous sources, those generated through primary production outside of the waterbody, and autochthonous sources, those generated through both benthic and pelagic primary production within the waterbody. Lake Diefenbaker, a large prairie reservoir located on the South Saskatchewan River in central Saskatchewan, contains an additional carbon source for consumers via waste products from an aquaculture facility located within the reservoir. This study set out to identify the importance of each potential carbon source to four common fish species throughout the length of Lake Diefenbaker. Lake Whitefish (Coregonus clupeaformis), Northern Pike (Esox lucius), Walleye (Sander vitreus) and White Sucker (Catostomus commersoni) were sampled in 2012 and 2013 and the importance of each potential carbon source was examined using stable isotope analysis and the Bayesian mixing model SIAR. Lake Whitefish in the area surrounding the aquaculture facility were using the waste feed from the fish farm as a diet subsidy; however, the effect was extremely localized and only fish in the immediate vicinity of the cages showed any contribution from aquaculture waste. Whitefish feeding on the pelleted fish feed were larger in size and in better condition than those that were not using the diet subsidy. Benthic autochthonous primary production was the most important source to Northern Pike, Walleye and White Sucker, while pelagic autochthonous production was the primary source supporting Lake Whitefish throughout the reservoir. Allochthonous carbon was of little importance to any of the fish species studied throughout the downstream reaches of Lake Diefenbaker, but was of slightly higher importance at the most upstream site in the riverine zone of the reservoir.
Description
Keywords
stable isotope, allochthonous, autochthonous, carbon sources, lake whitefish, northern pike, walleye, white sucker, Lake Diefenbaker, reservoir, food web
Citation
Degree
Master of Science (M.Sc.)
Department
Biology
Program
Biology