Perhaps sharks are water werewolves. Marine biologists studied more than 50 years of global data from the International Shark Attack File and found a clear correlation between shark attacks and the fuller phases of the moon. From LSU:
"It's not a matter of more light at night for sharks to see. Most shark attacks occur in the daylight. However, the moon can exert other forces on Earth and its oceans in ways that are much more subtle—for example, the gravitation pull that we see affect the tides," Steve Midway, LSU associate professor and researcher on the project said[…]
The scientists say it is still too early to demonstrate that lunar illumination is a causative factor for shark attacks. However, their new data serves as a building block towards better understanding shark attacks and could be useful for developing recommendations for water-based recreational activities in the future.
"Shark Side of the Moon: Are Shark Attacks Related to Lunar Phase?" (Frontiers in Marine Science)