Abstract for: Dynamics of Fisheries
In this paper, using a system dynamics approach, we develop a model to investigate the effect of industrial fishing on the average body size of targeted fish populations. Our model demonstrates that in the absence of fishing, larger fish would dominate the fish population as suggested in the biology literature. However, in presence of heavy fishing activity, population of larger fish collapses. We model the adaptive behavior of fishermen in choosing smaller gear sizes as fish become smaller over time. We observe that a side effect of this adaptive behavior is an increase in the ratio of catch of untargeted fish species to targeted one. This issue is called bycatch and is disliked both by environmentalist and fishermen.