Page from one of the dorsal fin albums
Dorsal Fin Identification

Cindy and the other scientists take photographs of the dolphins' dorsal fins to compile a catalogue of all the different individuals they see from the boat. This way they can tell which dolphins are most often together, which dolphins frequent particular areas, or where they travel.

The dorsal fins of the dolphins are very distinctive and the different nicks and notches can be used to tell the dolphins apart. The trailing edge or back part of the fin is often damaged, usually by sharks that attack the dolphins. The front part of the fin is called the leading edge. It is much thicker and is not damaged as severely or easily.

The dorsal fin photographs are placed into albums and numbered. There are albums with fins showing 1 notch, 2 notches, 3 notches, 4+ notches, leading edge notches and top notches. Altogether there probably over 1,000 photographs.

One of our tasks is to take the photographs that have just been taken (for example the ones that Cindy took with the digital camera on the boat), download them from the camera onto the computer, and look for a match in one of the albums. It is not easy. It is like a line-up of mug shots when a witness is trying to identify a criminal.

This is the album page showing "Woggle's" dorsal fin number 265.
Well what luck! Romy and I were able to find three matches so we got to choose names for the dolphins!!! Romy called her dolphin, Romy. I called my two, Judy and Woggle ( Woggle is the name of my class's toy bear).

It is really exciting to get matches and everyone wants to have another go.

You can try, too. Look carefully at the four photos of fins in the album (left) to see which one matches up with the digital photo on the computer screen (right). If you find a match, give the dolphin a name! This means that your dolphin has been sighted at least one time before, and the scientists have a record of both locations.

Here is a match made by an Earthwatch team member in February. The photograph book is on the left. The unidentified dorsal fin shown on the computer is on the right. Can you tell where the match is?

Photo courtesy of Alice McWilliams)