Using Aerial Behavior to Predict Remora Presence in Hawai'i Island Associated Spinner Dolphins (Stenella longirostris longirostris)

Abstract

Gray’s spinner dolphin (Stenella longirostris longirostris) is a species of spinner dolphin associated with Hawai’i Island. This species has a unique 24-hour schedule involving traveling offshore to forage at night and then migrating back to shore to rest in bays during the day. While in these bays, spinner dolphins come in close proximity to humans. A factor in determining the impact of human interactions with dolphins in the bay is understanding the behavior of spinner dolphins. Spinner dolphins known for the aerial behavior of leaping in the air and spinning. There are several hypotheses as to the function, or functions, of this behavior such as communication or removal of remoras (Remora australis), which are hydrodynamic parasites that attach to the body of dolphins and negatively impact their health. This study used a generalized linear model (GLM) to assess if the aerial behavior of the spinning leap can predict remora presence on spinner dolphins off the coast of Hawai’i Island. The study found that the aerial behavior of spinning leaps is not statistically significant in determining remora presence on a spinner dolphin. This finding compliments other research suggesting that spinning is not used primarily for remora removal.