Dolphin Ahoy (Under the bow)

I was quite excited to spot a dolphin under the bow of the ship (Sea Goldcrest) leaving harbour. I have seen them occasionally in the harbour entrance, but never before spotted one having a race with a ship leaving harbour. I wonder how far out it went before deciding to call off the race. I have cropped the photo to the bow area of the ship in the extra. Unfortunately this was really beyond the range of the longest lens I have for the camera.

Please don't tell me it is just a mark on the sensor, or on the lens, or even a figment of my imagination!

The weather forecast was very promising, probably the warmest day of the year so far. In fact it was 17º when I took this photo. It did not feel like it though. The wind was still cool, and the wind chill spoilt what might otherwise have been a very nice afternoon. There was also a lot of cloud.