Lunar patterns in dolphin foraging
Acoustic Ecology & Oceanography
In a world largely devoid of light, marine predators pursue prey that are sparse, fleeting, and mobile. I study the sounds of dolphins to understand their behavior over a range of time scales. A combination of passive and active acoustic techniques are used to study how predators respond to the movements of potential prey.
My PhD dissertation research explored how four different dolphin species optimize their foraging behavior with the lunar cycle. I studied common dolphins and Risso's dolphins in the California Current, and pilot whales and false killer whales around the Hawaiian Islands.
I documented consistent observations of reduced dolphin acoustic activity during times of increased lunar illumination. With more moonlight, some fish and invertebrates remain in deep, dark waters which are more difficult for dolphins to reach. The nocturnal foraging behavior of dolphins was shown to be optimized in response to the changing distribution and abundance of their prey throughout the lunar cycle.
An open-access article exploring this phenomenon with common dolphins in Southern California can be read in the journal Marine Ecology Progress Series.