Can fed aquaculture growth alleviate overfishing and foster the conservation of wild fish stocks? To examine this question we present a stylized fishery model of trade in edible fish and fishmeal that incorporates both market linkages and biological (predator–prey) linkages between the aquaculture sector and capture fisheries. We study the effects of local aquaculture growth, as induced by an increase in aquaculture feed-efficiency (technology shock), and of external or global aquaculture growth as experienced by either a drop in the price of edible fish or as an increase in the price of fishmeal (price shocks). While domestic (or “local”) aquaculture growth increases wild fish stocks due to positive market interactions, the effects of external (or “global”) aquaculture growth are generally ambiguous and depend on the strength of biological linkages. A stylized empirical application of the cod (predator) and capelin (prey) fisheries in the Barents Sea illustrates that the biological linkages between cod and capelin reduce the positive impact of aquaculture on cod conservation roughly by 50%.

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全球水产养殖的增长能否帮助保护野生鱼类资源？理论与实证分析

饲喂水产养殖的增长能否缓解过度捕捞并促进野生鱼类种群的保护？为了研究这个问题，我们提出了一个程式化的食用鱼和鱼粉贸易渔业模型，该模型结合了水产养殖部门和捕捞渔业之间的市场联系和生物（捕食者-猎物）联系。我们研究了由水产养殖饲料效率提高（技术冲击）引起的当地水产养殖增长的影响，以及由食用鱼价格下降或价格上涨所经历的外部或全球水产养殖增长的影响鱼粉（价格震荡）。虽然由于积极的市场互动，国内（或“当地”）水产养殖增长增加了野生鱼类种群，但外部（或“全球”）水产养殖增长的影响通常不明确，并取决于生物联系的强度。对巴伦支海鳕鱼（捕食者）和毛鳞鱼（猎物）渔业的典型经验应用表明，鳕鱼和毛鳞鱼之间的生物联系将水产养殖对鳕鱼保护的积极影响降低了大约 50%。