Due to the recent advances in digital photography, the technique of photo identification has been used in two of my most recent cetacean studies and efforts as a marine biologist. As such, I believe that Photo Identification holds vast possibilities for the future study on of a variety of species with even grander implications. You may find a brief introduction to the subject below. This Photo Identification introduction was completed in part by a fellow colleague by the name of Caeley Thacker, graduate of the University of Victoria. When our combined interest in the subject was spurred in the summer of 2008, we established a photo ID catalog of Grey Whales (Eschrichtius robustus) along the Southwest BC coast of Vancouver Island. The Photo ID Data basis was created at the Bamfield Marine Science Centre for the continual study of Grey Whales by staff and in part for the continual education of students working at the centre.
Photo identification of individuals was initially developed for studying the life history and movements of giraffes in 1966 (Daggand Foster 1976). Foster was interested in studying herd structure of giraffes in Nairobi Park and noticed that individuals could be identified by their unique pattern of dark blotches on its body. Foster photographed the neck of each giraffe from the left side, categorized the photos by sex and age of the animal, and then further subdivided by coat markings.
This method of identifying individual animals in wild populations has also been used for cheetahs in the central plains of Serengeti National Park in Tanzania. Photographing individual cheetahs began in the early 1960s and has continued to the present day. Researchers noticed that, like giraffes, cheetah pelage shows unique spot patterns that remain constant through life, allowing for individuals to be recognized and followed through time (Kelly 2001). More recently, 3-D computer-matching systems have been used to process and match photographs of cheetahs to identify individuals. As the surface of the head or flank of a cheetah is non-planar, the coat pattern changes with different postures or camera angles. This model-based computer-matching system accounts for this and makes matches by recognizing corresponding points, such as shoulder and hip, on pairs of photos (Kelly 2001).
Many marine mammal species have been studied using photo-identification techniques, including 27 cetacean species (Kelly 2001). Whale photo-identification studies first began in the 1960s and 1970s (Mizroch2007). Initially, researchers used either 35 mm slide film or high-resolution black and white film to document individual whales. From this they could determine distribution and migration, calving rate, and age of sexual maturity of whales by photographing whales in feeding areas and breeding grounds (Mizroch et al. 1990). In 1990 The International Whaling commission (IWC) compiled studies on marine mammals that have used photo-identification and computers to assist in matching photographs of new individuals (Hammond et al. 1990). For many species, the photograph collections are large and the need for accurate programs and organized databases is substantial. Since 1990, the technology has increased tremendously for computer-based photo-identification and has become specialized for cetacean species (Kelly 2001).
Literature Cited:
Dagg, A.I. and Foster, J.B. 1976. The Giraffe: Its Biology, Behavior, and Ecology. Van Nostrand Reinhold Company. New York. Pp 115-117.
Hammond, P.S., Mizroch, S.A. and Donovan, G.P. 1990. Individual Recognition of Cetaceans: Use of Photo-Identification and Other Techniques to Estimate Population Parameters. Report of the International Whaling Commission. Special Issue 12.
Kelly, M.J. 2001. Computer-Aided Photograph Matching in Studies Using IndividualIdentification: An Example from Serengeti Cheetahs. Journal of Mammalogy. 82(2): 440-449.
Mizroch, S.A., Beard, J.A. and Lynde, M. 1990. Computer Assisted Photo-Identification of Humback Whales. Rep. Int. Whal. Commn. Special Issue 12.
