An Alternative Photo-Identification Technique For The Mediterranean Monk Seals In The Northeastern Mediterranean

The Mediterranean monk seal (Monachus monachus, Hermann 1779) has been listed as one of the most endangered mammals in the world. Due to its rarity, vulnerability and critical status, use of photo-identification is one of the widely used approaches to obtain essential data on these animals such as their population structure, migration behavior and critical habitats. In this study, 3D model construction from photographs was tested as an alternative photo-identification method for the monk seals since it does not only enable researchers to identify individuals but also allow them to compare the same individuals in time and different individuals to each other without handling them. This technique is based on matching the points on a set of photographs of the same object taken from different angles. 3D model construction process was performed by using the photogrammetry software Photomodeler Ver.3.1a. In order to obtain suitable photographs for the software, some of the caves that are suitable for seal use were equipped with Vigil P-Box infrared monitors that may detect a seal up to 18 meter distance with a passive infrared motion detector and sense heat-in-motion with its conical beam. Besides, to choose sufficient and appropriate reference points that precisely describe the shape of the monk seal, the object having true proportions of a monk seal was used to estimate the minimum number of reference points. According to 3D model results, at least 4 cameras should be placed horizontally in a way to capture lateral, anterior and posterior aspects of the animal and at least 100 reference points should be defined. Additionally, using wider angle lens and infrared film as well as improving the light source may enhance the quality of photographs and so may improve the method.
Citation Formats
M. Ok and A. C. Gücü, “An Alternative Photo-Identification Technique For The Mediterranean Monk Seals In The Northeastern Mediterranean,” 2009, Accessed: 00, 2021. [Online]. Available: