By Andrew Ragas Smallmouth bass and rusty crayfish in northwoods inland lakes are on a collision course every summer. This predator and prey interaction often utilizes the same lake and river locations for habitat and feeding. Their connection as predator and prey is strong and unique, and shapes the ecosystems and food chains of ever fishery. On our northwoods lakes that are populated by them, rusty crayfish make up 60% to 80% of the smallmouth’s diet. There are so many present on some lakes that smallmouth can eat often and whenever they want. Big smallmouth sizes and trophy statuses are achieved and maintained through a rich diet of over-abundant native and non-native rusty crayfish. The invasion of crayfish in Wisconsin's lakes during the 1980's resulted in new species introductions of smallmouth that were previously not native to some lakes. For more than 20 years, their fisheries have flourished. How these fisheries reached this point dwells on the existence of a friend and foe; rusty crayfish. This invasive is responsible for many of the smallmouth fisheries we have today.   The History of Rusty Crayfish in Northern Wisconsin Lakes Rusty crayfish we