Flipper, Where Art Thou? Tracking Dolphins Up and Down the Coast

Bottlenose dolphins traveling along the California coastline. Photograph by Maddalena Bearzi/Ocean Conservation Society under NOAA permit.

By Maddalena Bearzi

Have you ever wondered where dolphins go after you get a glimpse of them as they surf a wave or catch a bow-ride off your boat? I surely did.

Bottlenose dolphins off California, one of the marine mammal species I’ve studied in this stretch of the Pacific Ocean for almost two decades now, are known to occur here in two distinct forms. There are coastal bottlenose, usually frequenting shallow waters less than one mile from the shore, and offshore bottlenose, found primarily in deeper pelagic waters. The coastal bottlenose are among the cetaceans best known worldwide and those most familiar to the general public, thanks in part to the famous Flipper that epitomizes this species.

Although I have observed and recorded these animals’ behavior in the wild for half of my life, I do realize that we are still just scratching the surface of what we know about these amazing creatures. Take for instance their movements: where do they go after they disappear in the fading sunset at the end of our research survey?

Based on year-round, boat-based monitoring studies conducted with my team off Los Angeles since the late 90s, the coastal bottlenose individuals that I have come to recognize spend a large amount of their time feeding in the Santa Monica Bay. This area seems to be a great dining hotspot for them, likely due to its unique bathymetry. These dolphins, however, are not true Los Angelinos in the sense that they tend to stay here only on a seasonal basis, and then wander somewhere else. I learned this by collecting behavioral data on them and taking pictures of their dorsal fins using a process known as photo-identification. The dorsal fins work as human fingerprints due to distinctive notches on their trailing edges and these nicks can tell —> Read More