The model used to assess the economic effects of management scenarios is based on the age-structured FishrentAge
model, which is an extension of the Fishrent model (Salz et al., 2011). Fishrent is a fleet based bio-economic model which
includes a detailed cost and earnings structure of multiple fleets. Multiple species can be included in the model and the
catches and stock biomasses of these species are age-disaggregated in the FishrentAge model. Furthermore, fish prices
are disaggregated according to the age of the fish as well as the fleet segment. The model is dynamic and is able to simulate
the development over time of fleets, landings, stocks and the economic performance of the fishing fleets through a set of
management rules. The investment module allows the fleet segments with positive profits to invest in new vessels and fleets
with negative profits to disinvest. A detailed overview of the Fishrent model can be found in Salz et al. (2011). The basis of
the FishrentAge model used in the present context is simulation and maximisation of the total net present value (NPV) for
the entire fishery, where the NPV is defined as: