Nuclear bomb detonation produces a small amount of local I-131 fallout. Most I-131 distributes over large distances, typically with only 10% making its way to the earth’s surface before undergoing spontaneous radioactive decay to stable xenon-131.
Dolphins have pretty good eyesight underwater. As their eyes are located on either side of their head, the dolphin’s range of vision is wider than a human’s, including being able to see objects located behind them.