'Fish Bioenergetics 4.0' Model Implementation with High-Performance 'TMB' Backend R package fb4package version 2.1.0 An implementation of the 'Fish Bioenergetics 4.0' framework described in Deslauriers et al. (2017) <doi:10.1080/03632415.2017.1377558>. Provides automated parameter optimization, multi-prey diet modeling, and comprehensive energy budget simulations for fisheries research and aquaculture applications. An optional 'TMB' (Template Model Builder) backend delivers 10-50x speedup in maximum likelihood estimation while maintaining full backward compatibility. Includes species-specific parameter databases and tools for modeling fish growth, consumption, and metabolism under varying environmental conditions. Software Depends: R (>= 4.0.0) Imports: graphics, grDevices, stats, tools, utils, Rcpp, TMB (>= 1.7.0) LinkingTo: TMB, RcppEigen Suggests: testthat (>= 3.0.0), knitr, rmarkdown, pkgdown, microbenchmark, future, furrr, spelling Hans Ttito <kvttitos@gmail.com> Comprehensive R Archive Network (CRAN) Hans Ttito [aut, cre] MIT + file LICENSE (https://CRAN.R-project.org/package=fb4package/LICENSE) 2026-06-09 application/tgz https://CRAN.R-project.org/package=fb4package doi:10.32614/CRAN.package.fb4package en-US