Date of Award
5-2016
Document Type
Thesis
Department
Biology
First Advisor
Andrew Hafs
Abstract
The Tamarac River is a major tributary of the Red Lakes MN, which provides an economically important multispecies fishery. The river experiences spring spawning migrations of northern pike, walleye, and white suckers. However, limited data exists related to reproductive success of fishes in the river. Furthermore, in the previous decade large congregations of American white pelicans (AWPE) have been observed using the Tamarac River as a foraging ground each spring. Assessing reproductive success of fishes in the Tamarac River provides a more holistic understanding of fish ecology in the river and the importance of the Tamarac River to the Red Lakes walleye fishery. Additionally, quantifying AWPE consumption in the river allows for assessment of the possible impacts of AWPE predation on the Red Lakes walleye fishery. Aerial surveys, diet composition data, and a bioenergetics model were used to estimate AWPE consumption of fishes in 2014 and 2015. AWPE diet was primarily composed of walleye (99.5%) and AWPE consumption in 2014 and 2015 accounted for 1.46 and 0.09% of the mean walleye annual natural mortality in the Red Lakes, respectively. Walleye spawning habitat was assessed using side scan sonar mapping that provided 78.0% overall accuracy when used to predict suitable spawning substrate. Side scan sonar mapping yielded an estimate of 26,398 m2 of suitable walleye spawning substrate that was accessible in 2015. The estimated area of suitable substrate represented 8.4% of the total riverbed mapped. Drift nets were used to evaluate temporal and spatial variations of larval fishes and provided evidence to suggest horizontal position in the river influences larval densities in multiple species. Low walleye larvae catch provided evidence to suggest low dissolved oxygen concentrations associated with high water levels resulted in high walleye embryo and/or larvae mortality.
Recommended Citation
Graham, Jake, "Assessment of American White Pelican Predation and Reproductive Success of Walleye in the Tamarac River, MN" (2016). Biology Graduate Theses. 12.
https://pines.bemidjistate.edu/thesis-biol/12
Included in
Aquaculture and Fisheries Commons, Biology Commons, Environmental Monitoring Commons, Laboratory and Basic Science Research Commons, Natural Resources and Conservation Commons, Other Environmental Sciences Commons, Population Biology Commons, Terrestrial and Aquatic Ecology Commons
