'Fish Bioenergetics 4.0' Model Implementation with High- Performance 'TMB' Backend // 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.