Development of a multispecies size-spectrum model for a fish community in the East China Sea

This repository contains the combined R code supporting two companion papers on multispecies fisheries modelling in the East China Sea (ECS). Paper 1 develops and calibrates a multispecies size-spectrum model (MSSM) for the ECS fish community, using a sequential calibration procedure to constrain maximum recruitment and reproductive efficiency, followed by historical stabilization and validation against independent size and yield data. Paper 2 uses this calibrated model as an operating model to evaluate four total allowable catch (TAC) management strategies (Business-As-Usual, Single-Species TAC, Multispecies TAC, and Hybrid TAC) assessing trade-offs between fishery production and population/ecosystem conservation indicators. The single file Code_Combined_Paper1_and_Paper2.R contains both papers' code, clearly divided into a Paper 1 section (calibration and validation) and a Paper 2 section (TAC scenario simulations, fishery production indicators, and population conservation indicators). Code is provided to support interpretation and replication of the reported results; some implementation-only detail not central to the reported findings (e.g., output-formatting and file-export routines) has been simplified for clarity.