The shifting trophodynamics in four southern Nova Scotia lakes after the introduction of Chain Pickerel (Esox niger)
*Delbert T. Swinemar1, Linda Campbell1, Darrin Reid2
1 Department of Environmental Science, Saint Mary’s University, Halifax, Nova Scotia.
2 Resource Conservation Manager, Parks Canada, Nunavut Field Unit. Previously Project Manager, Kejimkujik National Park and National Historic Site
Invasive fish species Chain Pickerel (Esox niger) was first reported within Kejimkujik National Park and Historical Site in 2018. We used stable carbon (d13C) and nitrogen (d15N) ratios to assess food web structure and trophodynamics in four four lakes ranging over an invasion spectrum: Loon Lake (first Chain Pickerel report in 2018), Grafton Lake (2019), Big Dam West Lake (2020) and Cobrielle Lake (2021). We found that E. niger can be grouped into two clusters based on their feeding habits, CP1 and CP2; 4.2cm ≤ TL ≤ 10.9cm and 20.2cm ≤ TL ≤ 58.6cm. Mixing model results indicate CP1 individuals feed primarily on Odonata with a mean dietary proportion of 0.736 ± 0.079. Those assigned to CP2 feed primarily on native fish with a mean dietary proportion of 0.724 ± 0.032. Post-invasion there was a consistent decrease in overall trophic position for fish and Odonata prey items.
Keywords: Stable Isotope Analysis, Chain Pickerel, Invasive Species
Downloadable PDF:
