Record Details

Challenges and opportunities for monitoring wild Nile crocodiles with scute mark-recapture photography

Verbum et Ecclesia

Field Value
Title Challenges and opportunities for monitoring wild Nile crocodiles with scute mark-recapture photography
Creator Coetzee, Bernard W.T. Ferreira, Sam M. Maciejewski, Kristine
Subject Conservation; Ecology Monitoring; Global Change; Tropical Studies; Crocodiles; Ecology; Anthropocene
Description The global conservation status of Nile crocodiles (Crocodylus niloticus) was last assessed in 1996. The species presents particular difficulty in monitoring because it can be cryptic, require expertise to handle, and caudal tail tags and transmitters are often lost. Some studies advocate mark-recapture techniques based on photograph identification of the unique scute markings of crocodile tails as a non-invasive means of monitoring their populations. Researchers developed this method with crocodiles in captivity. In this study, we test the technique under field conditions by monitoring crocodiles from 2015 to 2017 in the Sunset Dam in the Kruger National Park. Using a Cormack-Jolly-Seber open population model, we found that the dam may host 15–30 individuals, but that there is a high turnover of individuals and much uncertainty in model outputs. The dam’s population thus has high rates of immigration and emigration. The method proved challenging under field conditions, as there was bias in identifying scute markings consistently. The efficient use of the method requires an exceptional quality of photographic equipment. Animal crypsis, however, remains an issue. In this study, we discuss how to improve the mark-recapture photography methodology, especially to adapt the technique for citizen science initiatives.Conservation implications: Using scute mark-recapture photography presents challenges under field conditions. These challenges require innovative, practical and analytical solutions to successfully use the technique before monitoring programmes, aimed at ensuring the persistence of crocodiles in the wild, can be implemented.
Publisher AOSIS Publishing
Contributor Organization for Tropical Studies
Date 2018-07-19
Type info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion — Survey; Monitoring
Format text/html application/epub+zip application/xml application/pdf
Identifier 10.4102/koedoe.v60i1.1505
Source Koedoe; Vol 60, No 1 (2018); 5 pages 2071-0771 0075-6458
Language eng
Coverage Kruger National Park Anthropocene Density
Rights Copyright (c) 2018 Bernard W.T. Coetzee, Sam M. Ferreira, Kristine Maciejewski