I believe they were originally introduced in Oregon from fur farms that went under and the owners just turned everything loose. We were shooting nutria as kids back in the late 60's around the Columbia river north of Portland. I don't think anybody actually went out to hunt them other than trappers, they were just one of those animals like 'possums that were just there. You couldn't get anything for the hides then. We tried eating some, but it's not the best tasting, a little greasey and had kind of a muddy taste. But, it kept us off the streets and out of trouble. OK, so it didn't always keep us out of trouble. The canoe idea is a good one though, you can drift with the current and catch them along the banks. One thing you could try, is selling them to the fly tiers, they love getting that kind of fur to tie with, makes great nymphs.