I've been trying to find an image of a soft bodied seawater bug I found biting into my skin this afternoon as I paddled in the shallow waters off Fionnphort beach, across from the island of Iona on Scotland's west coast.
I noticed a little prick on the top of my foot left - two holes very close together and bleeding slightly. I then spotted a small, about 4mm or less round off-white, softbodied semi-opaque thing attached to my other foot still under the water. As I raised my right foot I could see it had penetrated my skin and I could see the blood flowing into it as it was attached. It was almost round as it was attached to me and I reacted by flicking it off before looking closer... my mistake.
Anyway, in years of wading about since I was a child, I've never seen this before so really no idea what it was? Anyone have any ideas?
I'm guessing that humans are probably not its primary interest and I was betting it probably was some kind of fish parasite that thought I was a handy snack.
I sounds like a fish louse (a crustacean of the order Branchiura) of the genus Argulus. Fish lice have been documented to very rarely bite humans (so you might have been extraordinarily lucky!). They seem to be most fond of eyes (and have been able to survive on the inside of the eyelid).