Studying the effect of camera tag associated white light on the diving and foraging behavior of Eastern Caribbean sperm whales

Abstract

Studying the behavior of animals roaming the deep-sea is challenging and is driven by technological developments. The next step to further understand the interactions between predators and prey in the deep sea may be aided by animal-borne camera tags. However, in the darkness of the deep sea, obtaining useful footage requires a light source, which may affect the animal carrying the tag as well as other nearby organisms such as prey. Here we have tested whether the presence of camera associated white light affects the foraging behavior of sperm whales in the Eastern Caribbean Sea. Based on a small dataset of 7 foraging dives with camera lights on, we observed no changes in diving behavior and overall biosonar search behavior. However, we did observed indications of fewer prey capture attempts, which may be due to light induced prey deterrence. For short camera tag deployments this likely does not affect the long term fitness of the whales. However, this effect should be considered and monitored for longer camera tag deployments. Importantly, different deep-sea communities may react differently, we therefore wish to highlight the importance of testing whether research equipment affects the studied animal and its surroundings.