Wool is absolutely rubbish in water. Throw a sheep in a lake if you don't believe us. The water soaks into the wool and turns the poor animal into a sad, soggy anchor.
That rubbishness is - conversely - rather useful when it comes to nets. The wool clods up, leaving barely any holes for a shrimp to make a getaway. It's also heavy as sin. The marine life is thoroughly pinned.
Now, getting the water out of the net: that's another matter entirely. You might do well to leave it out to dry in the Umbral Sands.