catRlog: a photo-identification project management system based in R

Eric M. Keen*, Julia Wren, Eadin O'Mahony, Janie Wray

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Photo-identification (photo-ID) databases can comprise versatile troves of information for well-studied animal populations and, when organized well and curated carefully, can be readily applied to a wide range of research questions, such as population abundance estimates, meta-population connectivity and social network structure. To bring the potential impact of photo-ID data within reach of a greater number of research groups, we introduce an R-based photo-ID project management system, named 'catRlog'. As a computer directory with custom apps embedded throughout, catRlog serves as a workflow organizer that simplifies, streamlines, and improves the quality of photo-ID data processing. The system can be utilized by research teams in a number of ways, ranging from automated formatting and printing of a photo-ID catalog, to photo-ID matching, thereby creating and expanding a historical catalog, to processing of identification data to generate datasets necessary for site fidelity, mark-recapture, and social association analyses. As an R-based tool, the apps are open-source, cross-platform, readily customizable, and easily updated. catRlog has been tested using photo-ID databases of humpback whales (Megaptera novaeangliae) and fin whales (Balaenoptera physalus) within a mainland fjord system of Pacific Canada, but is a generalized system useful for almost any photo-ID project of any species in any habitat. A detailed user's manual and example dataset are provided.

Original languageEnglish
Pages (from-to)995-1004
Number of pages10
JournalMammalian Biology
Early online date5 Aug 2021
Publication statusPublished - 1 Jun 2022


  • Photo-identification
  • R
  • Shiny
  • Mark-recapture
  • Social network analysis


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