Mid-April might be too early. The "season" is usually mid-May, June, early-July, though it can extend (on either end) a bit, depending on a lot of variables.
On a soft-shelled crab sidenote: there is some serious soft-shelled crab "farming" in Gila Bend, AZ. Yeah, I know it's a long way from the ocean, any ocean (Gulf of California is still 50 miles away), but they are raising the crabs and have discovered the "secret" to getting them to molt - light/dark cycles, so they basically subject them to almost a disco-like strobe light atmosphere and they molt. I've had some in most seasons and they are good. They are, however, NOT New Orleans blue crabs, at least not by my taste. Also, the preperations have not been like Brigsten's or others in NO, so I would have a hard time comparing them directly. The operation has expanded to the point that they are shipping nationwide, last I heard, so some chefs might have soft-shells "out of season." BTW, no rub on any NO chef, but the all-time best soft-shells were chef Michael Dagenhart's, when he was exec. chef at Tante Louise in Denver, of all places.