Techno-economic assessment of ear-hanging and lantern net grow-out techniques in Atlantic Sea scallop, Placopecten magellanicus, aquaculture in the Gulf of Maine

Global scallop production has rapidly transitioned from a wild-capture fishery to an aquaculture industry over the past several decades. However, aquaculture of the Atlantic sea scallop (Placopecten magellanicus) in the Gulf of Maine has remained limited by the high labor burden and costs within the United States and Canada, particularly when using traditional lantern net culture. As a result, specialized ear-hanging equipment designed to automate husbandry processes is increasingly being employed in scallop aquaculture to reduce labor, despite the higher initial investment. Here, we used a techno-economic model to compare the cost of production, net present value, modified internal rate of return, lease size requirements, and labor-bounded maximum annual production of automated ear-hanging and traditional lantern net culture, production cycle duration, and market products. While ear-hanging entailed higher initial capital expenditures, it was notably more cost effective compared to lantern net culture; the advantages were compounded at larger production scales, longer production cycle durations, and when targeting an adductor muscle market. Labor efficiencies in ear-hanging related to a total annual production capacity of almost double that for lantern net culture and a lease acreage reduction of 40 % at comparable annual production. We recommend that growers looking to scale scallop production (>100,000 annual production) consider automated ear-hanging targeting an adductor muscle product. Meanwhile small-scale growers (<100,000 annual production) would likely need to adjust assumptions for a profitable business model. To assist growers in this decision-making process, we have included a scenario-testing application to adjust assumptions to fit their specific business requirements.