Catfish is a very popular fish in our area of the states. The farm-raised variety is widely available in supermarkets and has a very mild flavor.
Salmon has been a staple of Northwest cuisine throughout known history, as have blueberries, both wild and cultivated.
My husband loves bagels and salmon. And he loves a great pastrami sandwich. Using the salty pastrami instead of bacon on a salmon burger married those flavors.
The Pacific Northwest is known for its fresh, flavorful salmon and delicious berries. I have always enjoyed blueberries, and thought that they would complement the mild salmon flavor.
The texture of flounder just lends itself to making a ground burger with few extra ingredients to hold it together.