Matching Fluke Photographs

Fortunately, as humpbacks descend on deeper, foraging dives, they arch their back steeply and often raise their flukes or tail into the air. If positioned correctly, you can snap a photo of the ventral side (underside) of their flukes as they are diving. This photo can then be used to identify each animal. A close look at a good fluke photo can reveal specific markings that are unique to each whale. This method was pioneered by Juneau researchers Chuck Jurasz and Virginia Palmer in the 1960's.

Humpback flukes have much natural variability in their shape and coloration (pigmentation). The two photos below are an example of this variability. In particular, notice the difference in fluke shape between the two whales.
Further, scarring on the flukes is common and tends to be lasting. Though, some scars will disappear and others can be added over time. Interestingly, areas with white pigmentation will scar black, and areas with black pigmentation will scar white. Below, are a couple of examples of scars that become helpful in identification.
Using scars alone for purpose of identification can be misleading. Just remember that a whale can acquire a scar in the time between the first and second photos being taken. Also, scars can change in appearance and severity over time, and look different depending on the lighting. The following two fluke photos are from the same whale, notice how the scars are more apparent in the photo on the left.
In this case, it is necessary to match the fluke using the trailing edge (see labeled fluke below). This process involves a lot of squinting and a fair amount of patience, but it is often the only way to make a positive identification.


Parts of the flukes

This photo outlines the terminology that is used to describe the different features of whale flukes.
When matching fluke photos, there are some tricks to make it simpler.
  • Keep in mind that some markings can be acquired in the time between taking each photo

  • When possible, use the trailing edge to confirm a fluke match. This tends to remain fairly stable through the whale’s life, and thus, is a reliable tool in identification.

  • If you have access to photo editing software, there are some tools that can help “bring out” details and markings on a fluke that may otherwise be difficult to see. First , rotate the image so the fluke in the image is not slanted in the frame. Next, crop the photo so the fluke is the majority of the frame. You can alter the exposure of the photo by increasing and decreasing the gamma and contrast. It is not advisable to use the other exposure options, as those editing options are more dramatic and could make some markings “appear” that are not actually there.

  • If possible, use photos that are the same size. This can be done by cropping your photo to a designated size, , such as 2x3.

  • Be sure to always keep a copy of the original photo in case you want to go back to it.