That's awesome!
It's a strange thing that it's relatively common for dolphins or whales to come into the harbour, yet it's very easy to never see them. You have to be looking at the right place at the right time, and most of us don't spend much time within view of the water let alone actively watching.
I spent a couple of years in an office overlooking the harbour, there were dolphins or whales in the harbour about half a dozen times that I knew of, but I only one saw a whale and only once very briefly. Never saw dolphins from that view.
The linked blog post explains about the vulnerability, I thought it was quite interesting.