2017 LAKE STEWARDS NEWSLETTER | 7 Lake Trout by Adam Jeziorski About this Fish Lake trout (Salvelinus namaycush) are a popular sportfish native to North America and can be found in many Ontario lakes on the Canadian Shield. Habitat As many lake trout lakes are near the southern limit of the species’ range, lake trout tend to live within narrow temperature and oxygen boundaries in the cool, deep waters of stratified lakes. Life Cycle Lake trout spawn in the fall, preferring regions of the lake bottom covered in boulders or rubble. They are a large- bodied fish that is both long-lived (usually 10-20 years) and slow to mature. Therefore, lake trout have low recruitment rates and are vulnerable to over-exploitation, competition for food with introduced species, and habitat loss. Predators & Prey Adult lake trout are apex predators that feed on forage fish, but can switch to a planktivorous diet when necessary. Other Interesting Facts Due to their popularity as a sportfish, lake trout have been intentionally spread beyond their native North American range, and are considered invasive in some regions of the world. Status of this Species As a coldwater fish with narrow temperature and oxygen requirements, lake trout are vulnerable to rising water temperatures associated with climate warming and excessive nutrient loading to lakes. ABOUT THE AUTHOR Adam Jeziorski is a Research Associate in the Paleoecological Environmental Assessment and Research Laboratory (PEARL) at Queen’s University. Adam’s research uses invertebrate remains preserved in lake sediments to reconstruct past environmental conditions. Adam is currently working in collaboration with FOCA and Dr. John Smol, looking at how changes in deep water oxygen conditions are affecting lake trout habitat in lakes across Ontario. For more, visit http://post.queensu.ca/~pearl/ laketrout/index.html. WHAT LURKS BELOW? Ontario Fish Facts FOCA asked some of our fish expert friends to tell us about some of the species that you can find (or hope NOT to find) in Ontario’s waterways! Featured over the next pages: trout, muskellunge, walleye, carp, and (OK – not a fish, but still very interesting) freshwater jellyfish. image: Andy Metelka