These "so called" mink are real mink, an aquatic rodent. They are farmed in Oregon for a variety of products, including hypoallergenic soaps and the like. Their furs are used in the fur industry, and the farmers typically sell the carcasses as crab bait. Mink have a strong scent gland, making them an ideal bait.

http://www.furcommission.com/farming/role.htm

I purchased my bait at Sawyer's Landing, a small dock/launch crane/store about 5 miles upbay from Newport.

I used fish carcasses for a while until the sea lions began tearing my crabpots apart. I switched to chicken for a while, but the amount of crab caught dropped significantly. This last time out I used mink, and it worked as well as the fish did.