Successful conservation activities depend on reliable population information based on distribution, habitat use, or life history parameters of individual animals. To be able to assess whether a species is endangered, which conservational measures are most likely to be successful or whether these measures had the expected result, it is essential to have proper information on existing populations. The population information described above can only be gathered from many observations of individual animals during a period covering several years.

For recognition of individual animals, often tags attached to the animals are used. Tagging however, is invasive, costly and tags do not last a lifetime. It also induces stress and when a tag is lost (torn away) it may wound the animal. Photo-identification using natural marks such as spots and fin or tail shape is proven to be effective over the entire lifespan, it is relatively cheap and does not induce any stress or damage. The main disadvantage is that recognition of animals is based on manual inspection of the photo database. As more individuals are added to photo-identification databases with hundreds or even thousands of individuals, the manual matching process becomes extremely tedious and therefore looses accuracy. For many marine biologists the efficiency of their research is seriously obstructed by the absence of tools to assist the identification of individual animals from photos.

Automatic assistance in photo-identification takes away the only disadvantage of this superior technique compared with tagging. I³S is a free computer-aided photo-identification technique that relies on natural marks to identify individual animals. I³S has proven very successful in identification of these species based on their natural spots. I³S helps the researcher to extract the spot pattern and then compares this pattern against all animals in the database and shows the researcher the most relevant results. The most recent version of I³S is able to recognize 96% of recurring animals in the top 10. Upon addition to the photo database, I³S expects the researcher to provide information about the spot pattern. This step takes about one to two minutes. After this step, the search is entirely automatic and highly accurate.

You can use I³S free of any charge. You are allowed to modify it, copy it, and distribute it under the GNU Public License v2. For the application you can download the distribution file including the source code.