Just behind the Ikea Delft there are hundreds (if not thousands) walking on the bottom under the water. You don’t see the American crayfish swimming that fast, but if you wait long enough you can just see a few walking in the direction. They are crawling with the warmer humid weather from the puddle in the direction.
They shuffle along the Peace Rest Path without batting an eyelid. Whoever disturbs them during their journey can count on eagerly squeezing scissors. It uses the red crustacean to defend itself. Delft residents do not have to be really afraid of them, but experts do see American crayfish as a threat to biodiversity and water quality.