With regard to whales I find it amusing that pissing overboard is forbidden, but compared to when a when a 60,000 pound whale takes a dump it is insignificant. Now if you take offense to that, well that's just too bad.
I don't think the no discharge rules affect peeing overboard. Its the peeing into a container and pouring the container contents overboard that is prohibited. Same goes for the whale. If he took his dump in a bucket and emptied the bucket into the water, he would be in trouble!
Jim