Personally I’d use (expensive) tinned crab for the recipe.
I assumed that all non-native fish has been frozen and thawed on the Swiss fish counters?
Cherax destructor . Known as Yabbies in Australia.
I spent a great week once paragliding in NSW, wild camping next to a river and catching and BBQing yabbies most evenings.
Tins can be found in Asia stores in Zurich. The one at Kalkbreite http://www.newasiamarket.ch/NewAsiaMarket/ at leasts sells them. Or did the last time I went there.
If you want to try out Manor, the one is Rapperswil does have a Food section!
Fresh dressed crab fro Devon or Scotland... 5.99 GBP from the fishmonger! They would not let me take it back on the plane, bastards!
Some of the canned crab meat you can buy in French hypermarkets such as Carrefour and Cora just across the border, is excellent. If you happen to be travelling through Alsace, might be a good idea to get a few cans for when you cannot get fresh crab meat.
I bought once from the Asian store next to the Oerlikon train station (platform 8 side). you can check there.
The Migros 3M near my place has it (in small tin can).
Aligro in Silbern definitely sells them fresh swimming around a tank where they sell the fresh fish.... https://www.aligro.ch/pages/fr/produ.../poissonnerie/
Aligro has a big store in Schlieren with live crabs and lobsters in tanks. You have to be a "member", but you can sign up on the spot, get a temporary card, and walk right in and shop. The seafood section is in general very good, similar to in France.
OOps I meant Schlieren...... I second what Karl says. I do my weekly shop there. the selection is excellent across all things that I need....