WGNO

‘Shark Side of the Moon’: Study suggests shark attacks linked to lunar phases

A lemon shark at the surface of tiger beach

BATON ROUGE, La. (BRPROUD) — A new study conducted by Louisiana State University and the University of Florida suggests there may be a relationship between shark attacks and lunar phases.

The study, titled Shark Side of the Moon: Are Shark Attacks Related to Lunar Phase?, looked at nearly 50 years of data on shark attacks and found that all instances more shark attacks occurring than expected happened at more than 50% lunar illumination. Conversely, the study also found that all instances of there being fewer shark attacks than expected occurred at less than 40% lunar illumination.

Lunar illumination as a measurement is similar to what most people refer to as phases of the moon, but offers a quantitative value for what percent of the moon’s surface is illuminated. For example, zero percent illumination would be a new moon and 100% illumination would be a full moon.

The study noted that not only would sharks be far from the only animal to have behavioral patterns that may be affected by the moon, but that past studies have documented other shark behaviors such as movement and natural feeding patterns to be influenced by the moon.

The study did not attempt to answer what might be the cause of this relationship but still provided guesses to why it might exist.

“…[A] direct effect of moon phase may be the moon’s night-time illumination that changes an organism’s behavior based on visual cues, while an indirect effect might be the moon’s effect on tides or electromagnetic fields (Bevington, 2015), which then influence how organisms behave,” read the paper.

Despite the findings, the study concluded that lunar illumination by itself is not a practical way to determine risks of shark attacks but rather that the study “contribute[s] to a fuller understanding of shark behavior, which may help risk management in the future.”