I WALK my dog daily and she wears a muzzle to protect her from ingesting blowfish left by fishermen.
They either bury them or throw them back into the water. In either case, they are washed back on to the beach edge. Blowfish are highly toxic and can kill a dog or a child if eaten.
The poisonous fish should be bagged and put in the bin just as we dog owners must do with doggie poops. Name and address supplied.