Date of Award

2026

Document Type

Honors Thesis (Open Access)

Department

Colby College. Environmental Studies Program

Advisor(s)

Caitlin Cleaver

Second Advisor

Jennifer Meredith

Third Advisor

Kanae Tokunaga

Abstract

Populations of wild and farmed quahogs in Maine are expanding, driven by warming waters, declining soft-shell clam populations, and the need to diversify fisheries. The Northern quahog (Mercenaria mercenaria) is a potential species to diversify Maine’s marine sector, as its geographical range is expanding, and they appear more resistant to green crab predation. Enhancing wild quahog stock provides economic and social advantages for both the aquaculture and wild harvest industries. However, there is limited understanding about the commercial viability of producing quahog seed on existing farms for wild shellfish enhancement in Maine. This research, part of a larger NOAA Saltonstall-Kennedy funded project, explores the economic and ecological viability of cultivating quahog seed on oyster farms for municipal stock enhancement in two different nursery systems. Quahog seed was deployed in early summer in both the FLUPSY and in lantern nets, and growth, husbandry techniques, survivorship, and costs were recorded periodically over two years, until quahogs reached a size greater than 10mm for municipal stock enhancement. Findings suggest that both systems successfully produced quahog seed large enough for municipal stock enhancement within one growing season. The FLUPSY produced seed that reached the optimal planting size faster, with higher survival rates and more uniform seed size, but required high initial investment costs. In contrast, lantern nets offered a low-cost, simple system that can be easily integrated into existing farms, but seed size was more variable, and a smaller proportion of seed reached the optimal planting size by the end of the season. The broader goal of the project is to develop quahog production strategies and market opportunities for wild harvesters and farmers to diversify Maine’s marine economy and build more resilient coastal communities.

Keywords

Shellfish aquaculture, quahogs, municipal stock enhancement, seed grow-out, fisheries diversification

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