Calculate the expected ecosystem effect of a management plan involving changing the fishing mortality on one aspect of the fish community from an "initial" fishing pattern to "new" fishing pattern. The fishing mortality is divided on three groups of fish species:
- Small species ("forage fish"): asymptotic weight less than 100 g
- Medium species ("small pelagics"): asymptotic weight between 100 g and 4 kg
- Large species ("large demersals/pelagics"): asymptotic weight larger than 4 kg.