Cyclical Patterns in Lake Whitefish Growth and Isotope Ratios and their Association with Climate

Session: Poster session

Issac Hebert, MNRF, [email protected]
Erin Dunlop, ON Ministry of Natural Resources, Trent University, [email protected]

Abstract

The average air temperature is increasing in the Great Lakes region, leading to higher water temperatures and reduced winter ice cover. Lake whitefish support important commercial fisheries in the Great Lakes, and there is little known as to how the species will be affected by climate change. Archived whitefish scale collections were obtained over several decades by Canadian and US agencies for three Lake Superior whitefish populations to assess growth rates and feeding ecology using stable isotope analysis.   Wavelet analysis was performed to examine cyclical patterns in growth and feeding ecology and their association with climate indices. Twelve climate indices were used to describe local and large-scale weather patterns. For both growth and isotopic signatures, all locations showed coherence with some climate variables. Climate affected the locations differently; the number of significant coherence plots and the coherence patterns differed between locations for growth and stable isotopes.  Spatial association between locations was apparent in the stable isotopes but not in growth rates.  Using these archived scale samples collected through long-term agency monitoring programs, we were able to determine that climate indices did have an influence on whitefish growth and feeding ecology but their association differed among locations.

1. Keyword
climatic data

2. Keyword
fish

3. Keyword
stable isotopes