Presentation Title

Do Invasive Yellow Perch Outcompete Rainbow Trout for Food? An Analysis of Fish Diets in Windy Lake, BC Prior to Chemical Treatment

Format of Presentation

Poster to be presented the Friday of the conference

Abstract

In 2016, yellow perch (Perca flavescens) were discovered in Windy Lake, a small lake between Merritt and Kelowna, BC. This was of concern, due to the ability of the species to compete for food resources among native populations of rainbow trout (Oncorhynchus mykiss) and mountain whitefish (Prosopium williamsoni), as well as potential for direct predation upon these species, which can reduce recruitment. The Ministry of Forests, Lands, Natural Resource Operations and Rural Development performed chemical treatment (rotenone) on September 27, 2017, which has presumed to kill all gill breathing organisms within the lake. 4 days were spent prior to treatment gillnetting and angling for all 3 species, and specimens were collected on the treatment day itself. Stomach contents of the 3 species were examined and enumerated in the lab to determine dietary trends and to compare the diets of the species. Preliminary results indicate that Oncorhynchus mykiss were favouring terrestrial insects as prey items, whereas Perca flavescens were favouring benthic (lake bottom) organisms as prey. A large percentage of stomach of both species contained dipteran (fly) pupae, and cladocerans (water fleas). These stomach content data may be compared to rainbow trout populations when they are eventually reintroduced to the lake.

Department

Natural Resource Science

Faculty Advisor

Brian Heise

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Do Invasive Yellow Perch Outcompete Rainbow Trout for Food? An Analysis of Fish Diets in Windy Lake, BC Prior to Chemical Treatment

In 2016, yellow perch (Perca flavescens) were discovered in Windy Lake, a small lake between Merritt and Kelowna, BC. This was of concern, due to the ability of the species to compete for food resources among native populations of rainbow trout (Oncorhynchus mykiss) and mountain whitefish (Prosopium williamsoni), as well as potential for direct predation upon these species, which can reduce recruitment. The Ministry of Forests, Lands, Natural Resource Operations and Rural Development performed chemical treatment (rotenone) on September 27, 2017, which has presumed to kill all gill breathing organisms within the lake. 4 days were spent prior to treatment gillnetting and angling for all 3 species, and specimens were collected on the treatment day itself. Stomach contents of the 3 species were examined and enumerated in the lab to determine dietary trends and to compare the diets of the species. Preliminary results indicate that Oncorhynchus mykiss were favouring terrestrial insects as prey items, whereas Perca flavescens were favouring benthic (lake bottom) organisms as prey. A large percentage of stomach of both species contained dipteran (fly) pupae, and cladocerans (water fleas). These stomach content data may be compared to rainbow trout populations when they are eventually reintroduced to the lake.