I quickly grabbed these shots as I walked on a dike. They were to remind me to look through all the shots taken on this trip.
The reason is… for no reason I could tell these guys came swimming around, all at the same time.

I saw no splashing in the water, nothing else to get their attention.

But at least 10, in different spots, swam towards the marsh shore.
No it was nothing to do with me.
I like to be aware of these things so when I see a sign I place myself in a position for the best possible photographs.