Quote Originally Posted by UncleChester View Post
The ones I've most often seen called Canadian Nightcrawlers are Lumbricus terrestris and they are native to Europe. They were introduced to North America with settlers to help with farming. As I understand it, most/many of our North American worms were wiped out in the last ice age especially in the northern regions and many of the species in these areas today are not native North American worms.

You're right they don't expand their territory very fast on their own, but don't underestimate the awesome powers of mankind to spread invasive species around willy-nilly and without regards to any consequences.



"Canadian Nightcrawler" might also be used for other species, but it's definitely non-native one that's pretty regularly seen in the bait shops under this name and also found in peoples yards.

Yep, I'm from MN and for most of the state worms are technically invasive. Certain parts of the state are night crawler free and you are not allowed to fish with them there. They change forest under story composition by altering the "duff" layer on the forest floor.