Most pearls on the market now-a-days are cultered pearls (farmed) rather than wild. However from what I read in the FWS article I linked, the Asial pearl farmers are using North American wild mussels as a source for shell fragments to seed their mussels.
....and if you look at fresh water mussels in Europe and N. America as a whole, then they're all pretty much under threat.
Slow maturity leaves them vulnerable, but awareness is a very good thing.
Not particularly good eating I was told
I really don't mind being allergic to fish
M
Apparently their means of reproduction also makes them vulnerable. They lure fish near enough to expel the larvae onto the fish's gills and fins where they remain until they are mature enough to drop to the water's bottom. Anything that interferes with the host fish species (such as overfishing or dams impeding fish migrations) has a knock on effect on the mussels as well.
I suspect those families might not be doing anything out of greed. The majority of the public probably have no idea of the environmental issues (face it, mussels aren't a high publicity creature) They're probably just thinking how cool it is to be able to dig them up. I confess I collected the shells when I was a young to mid teenager. We just didn't know any better and they seemed so plentiful then.
