Investigating the viability of photo-identification as an objective tool to study endangered sea turtle populations

By G. Schofield, K. A. Katselidis, Panayotis Dimopoulos, John Pantis. 2008

125 citations recorded by the source corpus.

We assessed the potential of using natural facial markings to identify individuals in an endangered breeding population of loggerhead sea turtles (Caretta caretta). We divided individual turtles into ten groups based on facial (post-ocular) scale patterns to facilitate rapid comparison of new images in a large photographic catalogue of known turtles (exceeding 400 unique individuals). The matching process was validated by using turtles marked with external flipper tags. An experienced observer achieved a mean 99% success in identifying individuals using photo-id. The reliability and wider utility of the technique was assessed through testing the ability of naive and trained observers to (1) consistently allocate known (i.e. flipper tagged) individuals into the correct groups (2) correctly match known individuals within one group. In all trials the mean success rate in photographic sorting and matching ranged from 68-100%. A 20 minute training session was found to significantly improve observer ability, i.e the photo-id skills were rapidly acquired by inexperienced workers. Photo-id has the benefit of being suitable for male turtles, which do not come ashore to allow conventional tagging, and so are rarely identified. Photo-id may facilitate the assessment of the numbers of male and female turtles at breeding areas and allow adult sex ratios to be measured.

Subfields: Ecology, Evolution, Behavior and Systematics, Global and Planetary Change, Nature and Landscape Conservation

View Paper: https://www.semanticscholar.org/paper/618296db3740b1cad79f653f5552d35a9f35a224

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In Ecology, Evolution, Behavior and Systematics

In Global and Planetary Change

In Nature and Landscape Conservation

Citations in the corpus

Satellite tracking large numbers of individuals to infer population level dispersal and core areas for the protection of an endangered species (2013, methodology): “All tracked turtles (males and females) were identified using a previously validated photo-identification system (Schofield et al., 2008) and external flipper tags (females only), with all turtles captured from 2008 onwards also receiving passive integrated transponders (PITs).”
Mediterranean sea turtles: current knowledge and priorities for conservation and research (2018, unknown): “Few data are available on loggerhead plastron and head scute patterns (Schofield et al. 2008, Margaritoulis & Chiras 2011, Oliver 2014, Casale et al. 2017).”