Smallmouth Bass impact Lake Trout Food Chain

Smallmouth bass in Ontario

The following is an example of the impact Smallmouth Bass had on Lake Trout in in the Great Lakes of Ontario.  Keep in mind, the majority of our lakes in NS are not as deep nor as big as in Ontario, therefore the issue of invasive Smallmouth Bass would be more severe in our province .

Smallmouth bass were historically confined to portions of Mississippi and Great Lakes drainages but have gradually been introduced and spread across much of Canada and the US (Rahel 2000). In particular, they have rapidly spread at the northern portion of their native range due to a combination of consistently warm summers during the past two decades, unauthorized introduction by anglers, and bait-bucket transfers (Jackson 2002; Jackson and Mandrak 2002).

Adult smallmouth bass are efficient piscivores and can have substantial predatory impacts on littoral prey fish communities in north-temperate lakes (Vander Zanden et al. 1999). In a study of nine Ontario lake trout lakes, bass invasion was associated with a sharp reduction in fish species richness and abundance in littoral zone habitats. Food-web studies revealed that native lake trout shifted from a diet of littoral fish to one consisting primarily of plankton following bass invasion (Vander Zanden et al. 1999). This food-web change has adversely affected lake trout growth rates, biomass, and productivity.