How defensive minefields could delay Germany in Norway

What if Norway had mined its major ports before the German invasion?

German forces would likely suffer losses and delays because minesweeping in defended fjords would be slow and dangerous.

Norway possessed mines, minelaying vessels, and even fishing craft that could help close port approaches. The German invasion relied on speed and limited reconnaissance, while its minesweeping resources were not abundant. In confined fjords, minesweepers would themselves become exposed targets for ships and coastal forts. Existing Norwegian minefields were aimed more at territorial control than at sealing the invasion ports, so a more deliberate defensive pattern could have imposed both casualties and delay.