Investigating spatiotemporal dynamics of fishes in response to changes in their physical environment

Session: Spatial Dynamics in the Pelagia of Large Lakes – Technological Advances and Applications

Bryan Flood, University of Toronto, [email protected]
Mathew Wells, University of Toronto Scarborough, [email protected]
Erin Dunlop, ON Ministry of Natural Resources, Trent University, [email protected]

Abstract

Large variability in pelagic fish abundance and spatial distribution observed via hydroacoustics over several consecutive days could be a response to changes in the physical environment. As part of an ongoing, long-term monitoring campaign aimed at understanding and restoring the fish community in Lake Simcoe, a large inland lake, 10 days of hydroacoustic surveys were taken during the stratified season, between September 8th and 17th, 2015. Substantial spatial and temporal variability in target density was observed over the hydroacoustic survey dates, which could be a response of the fishes to variations in their physical environment, in terms of temperature and dissolved oxygen (DO). We observed internal waves with amplitudes in excess of 10 m during the hydroacoustic surveys resulting in large variability in temperature and dissolved oxygen on timescales of hours to days. We expect the cold-water fishes in Kempenfelt Bay to respond to these significant variations in their physical environment, as these features influence their ability to survive and reproduce. Here, we present findings investigating the spatiotemporal dynamics of fish in a large lake, in response to changes in their physical environment (T & DO). Our research can inform monitoring campaign design, fishery management decisions, and habitat restoration efforts.