because they are wind assisted i doubt you will find too may fish in attendance Hadleigh....
finding a group like that would mean to me, they have been caught in a vortex of some sort...
i guess if enough covered a large area though it could act like a fad to some fish and they might be tempted to try hiding under them, but once the wind got up again it would be hard work for most bait fish to keep up with them...

They do tend to end up in rather tight packed groups at time, quite strange! I don't know if they affect fishing.