I shoot a lot, including tons of blue water whale images and I've never seen a reflection like that. Reflections come from sunlight hitting the front of the lens and reflecting in the dome port. You only ever see a section of the lens, not an entire circle. You'd have to shoot with the sun dead center in the frame for that to be possible.
I'd agree with troporobo - my best guess is post processing artifacts. It happens with blue water images quite easily.
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