Photo-id as an alternative to monitor marine turtles in the Gulf of Venezuela

Abstract

Conservation management programs have used diverse methods to monitor populations of threatened species that vary in effectiveness, duration, and costs; making its implementation a challenge. The present study was carried out to test the use of photo-identification as an economical and efficient alternative for marine turtle monitoring in the Gulf of Venezuela. The implementation of this protocol is possible due to the unique and unrepeatable facial scales pattern of individuals in the marine turtles. We created a database of photo-identifiable profiles available from records of turtles captured, tagged, and released in the Gulf of Venezuela from 2000 to 2017 (n = 118). Likewise, we used two photo-matching software (I³S Pattern and Nature Pattern Match) to optimize the process of compatibility of individuals and we evaluated their efficiency in comparison with the non-assisted manual method (“by human eye” or “by naked eye”). We found that I³S Pattern was more effective during the matching process than NPM (90 % and 65 % accuracy respectively), while the manual method was much more accurate than the software. However, the former method is impractical when working with large databases. Our results indicate that I³S Pattern represents the most efficient software of image matching by reducing the time needed and simplifying the manual “by human eye” analysis. We recommend incorporating more photos in the database in order to verify the effectiveness of both studied software, and regularly to corroborate the results generated by the software assessed on this research using the “human eye” manual method.