The Museum am Meer gives Büsum's small-scale fishing culture some useful depth. Exhibits cover coastal fishing, shrimp processing, tourism since the nineteenth century, and the way a North Sea spa town learned to live with tides and dikes.
It is a good rainy-day stop, but it also helps before or after a harbour walk. The shrimp boats outside make more sense once you have seen how much local labour and local pride sits behind a plate of Krabben.