This is only done at the end of the season and they aren't dunmped into the same pond rather the pond they will be using next year. A lot of crawfisherman rotate ponds every year so when the price falls to far they stock up next year's pond.

The problem these days are from almost everything everyone in here has said. Mostly the fact that you can now get crawfish all the way to Midland TX. Also people are eating more crawfish more often. Before you didn't have a crawfish restaurant on every street and people didn't typically eat crawfish except on Friday's and Saturdays. Now you pass these places on a Tuesday and they are packed.

The prices are set by the whole-sellers. The problem are there are only a hand full of them. They at talk every day and set a price so they don't undercut each other (granted larger crawfish will still get the farmer .10-.15 cents more a pound). People like Troy Landry (D&M Crawfish) control the prices. He buys crawfish from Eunice to Pierre Port. He is so big that he can damn near set the price himself. The reason he is so big is because he is loyal to his farmers. If you sell to Troy he will buy your crawfish every day you run. Other middle men will cut farmers off later in the season when the catch is high and the demand is low. Troy won't because any extra he has he send to his peeling plant so there is no waste in what he buys. (He may tell you not to run some days but if you run your field he will buy them).
As long as people are buying them though and restaurants are selling out the price won't move much until the catch really goes up. Still then though now a days there is a much high price floor than before because of Walmart and other big stores that now carry crawfish. They won't start buying crawfish tails until the per-pound live price hits ~$1.75 wholesale (not sure the exact price but somewhere around $60-70 a sack). Once that price is hit than Walmart starts buying from 2 peeling plants they have contracts with (one is D&M). Once Walmart starts buying it adds another demand on the crawfish and that is another reason why the price stays higher longer these days.

The other thing is the Basin. If water levels are right the Basin fisherman can flood the market with crawfish which drives the price down quite a bit.