Investigation into the ecological costs of sea lamprey control on lake sturgeon and ammocoete predators using olfactory techniques

Abstract

Fish that feed or travel in low light conditions particularly rely on their chemical senses, such as olfaction, for survival. Exposure to toxicants at concentrations lower than those causing mortality can have detrimental effects on olfactory senses. My research studied sea lamprey control from two ecological perspectives. The first was to determine if the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) affects the olfactory capabilities and behaviour of young-of-the-year (YOY) lake sturgeon (Acipenser fulvescens), reduces food consumption and induces a change in blood glucose and lactate. My methods utilized electro-olfactography (EOG), behavioural trials and blood analysis. The second part of my study investigated the attraction of lake sturgeon to the scent of lamprey ammocoetes as a food source, using chemosensory baits in four northwestern Ontario locations. Laboratory exposure of YOY lake sturgeon to TFM caused a reduced olfactory response to L-alanine, taurocholic acid and a food cue. It also reduced attraction to the scent of food and food consumption in the same species. Exposed fish were active for a higher percentage of time, but with slower acceleration. Fish were able to detect the scent of TFM, but did not significantly avoid it, which may expose fish to the full toxic effects. A number of small aquatic predators were attracted to ammocoete-conditioned baits. Healthy populations of these species may benefit sea lamprey control and help to restore ecological processes that would improve the functional performance of the Laurentian Great Lakes ecosystem.