In the 80's mussel fishing was big around these parts....seems everybody's brother was doing it for awhile and we had a lot of buying stations as well. Which I remember those stations had crates built with a solid plywood bottom that had multiple sized holes. You would bring your mussels in tubs or buckets and pour them into the crates and the buyer would "class out" the mussels according to fitting in a certain sized hole. I might be wrong but thinking "washboards" was the largest & highest class of shell ...but I've slept a few times since..lol. However .. it was some really good money in mussels back then. I'll also say ...the legal & proper way to fish for mussels was brailing hooks. But I'm doubtful that 25% sold was attained that way on the Ky portion of KY lake as most were gotten by illegal diving. Which as the price of mussels went up.. it got more competitive. Many operations resorted to diving at night trying to avoid getting caught. As such...many had some really crude rigs to supply breathing air to their divers ...and many cases it didn't end too well. Also... if I'm thinking right ... for several years diving for mussels on Ky lake was legal in Tennessee portion but not in Ky. So.. it was also a case of LE stopping a mussel boat and stumbling across some diving equipment ...they had a heck of a time trying to figure out where the mussels were gotten. It was a heck of a racket for awhile... and the mussels demise on the lakes around here was primarily because of the illegal aspect.