Integrated economic models have become popular for assessing climate change. In this paper we show how these methods can be used to assess the impact of a discard ban in a fishery. We state that a discard ban can be understood as a confiscatory tax equivalent to a value-added tax. Under this framework, we show that a discard ban improves the sustainability of the fishery in the short run and increases economic welfare in the long run. In particular, we show that consumption, capital and wages show an initial decrease just after the implementation of the discard ban then recover after some periods to reach their steady-sate values, which are 16–20% higher than the initial values, depending on the valuation of the landed discards. The discard ban also improves biological variables, increasing landings by 14% and reducing discards by 29% on the initial figures. These patterns highlight the two channels through which discard bans affect a fishery: the tax channel, which shows that the confiscation of landed discards reduces the incentive to invest in the fishery; and the productivity channel, which increases the abundance of the stock. Thus, during the first few years after the implementation of a discard ban, the negative effect from the tax channel dominates the positive effect from the productivity channel, because the stock needs time to recover. Once stock abundance improves, the productivity channel dominates the tax channel and the economic variables rise above their initial levels. Our results also show that a landed discards valorisation policy is optimal from the social welfare point of view provided that incentives to increase discards are not created.

综合经济模型已成为评估气候变化的流行方法。在本文中，我们展示了如何使用这些方法来评估禁止丢弃渔业的影响。我们声明，丢弃禁令可以理解为相当于增值税的没收税。在这个框架下，我们表明禁止丢弃在短期内提高了渔业的可持续性，并在长期内增加了经济福利。特别是，我们表明，消费、资本和工资在实施丢弃禁令后显示出最初的下降，然后在一段时间后恢复到稳定值，比初始值高 16-20%，具体取决于上岸丢弃物的估价。丢弃禁令还改善了生物变量，上岸量增加 14%，丢弃量减少 29%。这些模式突出了丢弃物禁令影响渔业的两个渠道：税收渠道，表明没收上岸丢弃物降低了对渔业投资的积极性；和生产力渠道，这增加了库存的丰富性。因此，在禁弃令实施后的最初几年，税收渠道的负面影响大于生产力渠道的正面影响，因为库存需要时间恢复。一旦存量丰度提高，生产力渠道就会主导税收渠道，经济变量就会上升到初始水平以上。