Spinning Ideas While Watching Spinners


On Saturday May 21st the Research Team went to sea on PWF’s raft Ocean Freedom to collect data on spinner dolphins (Stenella longirostris). The trip along the coast of Lanai Island was a unique opportunity to get new information on the behavior of these amazing creatures and their interaction with vessels.

We encountered dolphins early in the morning off Manele Bay, the little harbor that graces the south- east side of Lanai. This is a known resting area for spinner dolphins, which are known to come here early in the morning and use the sandy patch in front of the harbor. Spinners prefer light sand to dark coral because the background makes it easier to detect sharks and danger in general (more contrast!!).

Our goal was to follow the dolphins for as long as possible and determine their movement patterns and their level of energy during different times of the day and in the presence and absence of dolphin-watching vessels.

It is rare to have a long day in constant view of the dolphins. Today we were lucky…the day was beautiful and the sea calm for most of the day giving us a chance to follow this 60+ animals group of spinners for many hours, reporting their behavior, recording their sounds with a hydrophone, and shooting photos and videos for photo-identification.

The team, composed by Daniela, Itana, Cristina, Nick, Nico and Capt. Brock, worked really well together. Cristina (Chiccha) was radiant. She is working on her MS thesis on the dolphins and this was a wonderful opportunity to collect a lot of data in a single day.

We had several interesting moments. We realized that there are differences in the ‘meaning’ of spinning behavior depending on whether adults or calves are performing it. For calves, spinning is a joyful event, an expression of energy level and play behavior often followed by ‘scolding’ (a recall by the mother to come back to her by slapping the fluke on the water). It is also a time to learn proper spinning techniques. For adults spinning is much more a form of communication and an important tool for school cohesion.

The behavior of spinners is influenced by boats in many ways. We are trying to understand this better and we had to rethink some of the theories we were operating under…dolphins always unveil new information every time you watch them.

One thing we had never seen with spinners was surfing. Dolphins were taking turns riding 3-4 ft swells offshore Lanai in the afternoon. This behavior continued for some time. I have known of bottlenose being great surfers and enjoying the sport. But spinners….I had never seen surfing before. This is Hawaii after all and they are Hawaiians. It makes sense they enjoy surfing!!