Fluke = Fingerprint

30 06 2013
Humpback whales have patterns of black and white pigmentation and scars on the underside of their tails that are unique to each whale, just as fingerprints are to humans. Researchers document the marks on the right and left lobes of the tail, or flukes, and rate the percentage of dark vs. light skin pigmentation from 100 percent white to 100 percent black. For scientific purposes, each humpback whale sighted in the NorthAtlantic is assigned a catalog number. The unique scarring and shading patterns also provide the inspiration for common names. Young animals sighted in a second year. New calves are not named because their coloring and scarring often change dramatically during that first year.
The basics of a fluke.

The basics of a fluke.

Most whales have unique shading, spots, or a scar to aid in identification, but there are three other basic characteristics; fluke shape, trailing edge, and notch shape that help in identification. The shape of the flukes can change to some degree depending on the angle to the surface of the water the instant the photograph was taken. Typically, it is easiest to match photos taken when the flukes are straight up and down at a 90 degree angle to the water. Fluke shape is something that does not change drastically, unless the whale has had an injury. One of the most important areas of the flukes to look at is the trailing edge. The bumps and nicks along this edge remain relatively stable throughout the whale’s lifetime. (There are, of course always exceptions. A whale may lose a part of the trailing edge or even half of a fluke from an entanglement in fishing gear, an injury competing with other males in the breeding grounds, an attack from a predator, or an encounter with a vessel.) The notch, separating the flukes, is the final characteristic to use when trying to match your photograph. Some whales have very narrow notches and some have very wide notches. The notch is useful because the shape seldom changes.

This is the whale we named "Dot" because of the black dots. The central shading along with the dots make this whale easily identifiable. It is the same whale that breached yesterday and is a young whale, new to the bay this year.

This is the whale we named “Dot” because of the black dots. The central shading along with the dots make this whale easily identifiable. It is the same whale that breached yesterday and is a young whale, new to the bay this year.

Whales will also acquire new markings that change the appearance in more subtle ways. Injuries such as rake marks from a killer whale’s teeth, circular barnacle scars, scratches, and new nicks may make a positive match a bit more difficult.

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