Thread: Shooting at sea query

As per title, I was wondering what the laws were regarding shooting on the ocean/lake.
Went fishing a while ago and saw a couple of guys blasting clays. We were out the back of Mayor so not too much in the way of other people or obstacles etc.
Are we allowed to shoot at sea so long as it is safe to do so? Any restrictions on types of ammo that can be used?

Thanks for the help,

Dan