Browse by author
Lookup NU author(s): Professor Per Berggren
Full text for this publication is not currently held within this repository. Alternative links are provided below where available.
Capture-recapture methods are frequently employed to estimate abundance of cetaceans using photographic techniques and a variety of statistical models. However, there are many unresolved issues regarding the selection and manipulation of images that can potentially impose bias on resulting estimates. To examine the potential impact of these issues we circulated a test data set of dorsal fin images from bottlenose dolphins to several independent research groups. Photo-identification methods were generally similar, but the selection, scoring, and matching of images varied greatly amongst groups. Based on these results we make the following recommendations. Researchers should: (1) determine the degree of marking, or level of distinctiveness, and use images of sufficient quality to recognize animals of that level of distinctiveness; (2) ensure that markings are sufficiently distinct to eliminate the potential for “twins” to occur; (3) stratify data sets by distinctiveness and generate a series of abundance estimates to investigate the influence of including animals of varying degrees of markings; and (4) strive to examine and incorporate variability among analysts into capture-recapture estimation. In this paper we summarize these potential sources of bias and provide recommendations for best practices for using natural markings in a capture-recapture framework.
Author(s): Urian K, Gorgone A, Read A, Balmer B, Wells RS, Berggren P, Durban J, Egushi T, Rayment W, Hammond PS
Publication type: Article
Publication status: Published
Journal: Marine Mammal Science
Year: 2015
Volume: 31
Issue: 1
Pages: 298–321
Print publication date: 02/01/2015
Online publication date: 14/05/2014
Acceptance date: 25/03/2014
ISSN (print): 0824-0469
ISSN (electronic): 1748-7692
Publisher: Wiley-Blackwell Publishing, Inc.
URL: http://dx.doi.org/10.1111/mms.12141
DOI: 10.1111/mms.12141
Altmetrics provided by Altmetric
