Spatially Explicit Capture-Recapture R package secr version 5.4.3 CRAN Task View: Environmetrics (https://CRAN.R-project.org/view=Environmetrics) Functions to estimate the density and size of a spatially distributed animal population sampled with an array of passive detectors, such as traps, or by searching polygons or transects. Models incorporating distance-dependent detection are fitted by maximizing the likelihood. Tools are included for data manipulation and model selection. Software Depends: R (>= 3.5.0), methods Imports: secrfunc, abind, graphics, grDevices, MASS, mgcv, mvtnorm, nlme, parallel, raster (>= 3.5-15), Rcpp (>= 0.12.14), RcppParallel (>= 5.1.1), sf, stats, stringr, terra (>= 1.5-12), tools, utils LinkingTo: BH, Rcpp, RcppParallel Suggests: gdistance, igraph, knitr, readxl, rmarkdown, sp, spatstat (>= 3.3-3), spatstat.geom, spatstat.random, spcosa, spsurvey (>= 5.3.0), testthat Murray Efford <murray.efford@otago.ac.nz> Comprehensive R Archive Network (CRAN) Murray Efford [aut, cre] (ORCID: <https://orcid.org/0000-0001-5231-5184>), Philipp Jund [ctb] (faster transect search and spacing), David Fletcher [ctb] (overdispersion), Yan Ru Choo [ctb] (ORCID: <https://orcid.org/0000-0002-8852-7178>, goodness-of-fit) GPL (>= 2) 2026-05-27 application/tgz https://CRAN.R-project.org/package=secr doi:10.32614/CRAN.package.secr