This study aims to understand the economic and bio-physical conditions under which mussel farming is a cost-effective mitigation measure to improve water quality related to excess nitrogen in fjords and coastal areas. We set-up a mixed-integer optimization model including every farm in three agricultural catchments surrounding Limfjorden, the largest fjord in Denmark. We include a number of relevant nitrogen abatement measures, including agricultural land-use measures and mussel farming in the sea. The aim is to model the least costly combination of mitigation measures to improve water quality when agricultural, environmental and market conditions vary. We run three scenarios varying environmental conditions for mussel productivity and market opportunities for mussel-based products as organic animal feed. We analyze the resulting marginal abatement costs and draw insights about the potential scale of mussel farming for the different catchments. We show that mussel farming is a cost-effective option for 2 of the 3 catchments, but that decreasing mussel productivity over time may make the measure ineffective for one of the catchments, if a market for feed is not available. The possibility of a market for mussel-based organic feed significantly increases the share of nitrogen reduction done by mussels and decreases overall costs by up to 65%. Ultimately, the results indicate that, for catchments where environmental conditions are adequate, mussel farming can be a cost-effective nutrient reduction measure. Therefore, mussel farming can potentially increase the cost-effectiveness of incentive schemes aimed at reducing eutrophication in fjords and coastal waters.

这项研究旨在了解贻贝养殖是一种经济有效的缓解措施，以改善与峡湾和沿海地区与过量氮有关的水质的经济和生物物理条件。我们建立了一个混合整数优化模型，该模型包括丹麦最大峡湾Limfjorden周围三个农业集水区中的每个农场。我们包括许多相关的氮减少措施，包括农业土地利用措施和海洋贻贝养殖。目的是对农业，环境和市场条件变化时减轻污染措施成本最低组合的模型进行建模，以改善水质。我们运行三种方案，以不同的环境条件提高贻贝的生产力以及以贻贝为基础的产品作为有机动物饲料的市场机会。我们分析了由此产生的边际减排成本，并就不同集水区贻贝养殖的潜在规模得出了见解。我们表明，对于3个流域中的2个流域，贻贝养殖是一种具有成本效益的选择，但是随着时间的推移，贻贝生产力的下降可能会使其中一个流域的措施无效，如果没有饲料市场。贻贝基有机饲料市场的可能性极大地提高了贻贝减少氮的份额，并使总成本降低了65％。最终，结果表明，对于环境条件适当的流域，贻贝养殖可以是一种经济有效的营养减少措施。因此，