Why do I ask this question. Because the beginning of crayfish season is a great excuse to have a party despite the fact that the crayfish is a miniature lobster which to my palate has little taste.
Traditionally, the first crayfish party is held right at the beginning of crayfish season during the first week of August. Crayfish season starts on the first Wednesday of August. The traditional Swedish Crayfish Party first originated from a restriction in Sweden on the crayfish fishing season. Swedes were consuming so much crayfish that the crayfish population was being depleted in the area. Hence, there was a restriction put on the season to just a period of a couple of months, starting in August. When the season finally came around, the Swedes were so elated that crayfish parties started popping up everywhere. Since crayfish is so popular in Scandinavia, crayfish parties can be found all throughout Sweden and in a few other Scandinavian countries. I figure their might be a cruise line that celebrates this event.
The only time I've ever heard of Scandinvaia and crayfish was on an episode of Bizarre Foods with Andrew Zimmern, and in that episode he visited a family that harvests them in Finland but had never eaten them because they get so much profit by selling them. He cooked up a mess of them and the family didn't really like them, so they all ate the fish pie they cooked as a back-up.