Exploring the Feasibility of Selectively Breeding Farmed Atlantic Surfclams Spisula solidissima for Greater Heat Tolerance

Bivalve aquaculture is an important and rapidly expanding sector in global food production, yet climate change presents numerous challenges to its continued expansion. The Atlantic surfclam Spisula solidissima is emerging as an attractive alternate species for aquaculturists across the northeastern United States since it is native, grows rapidly, and complements the region’s established farming framework. However, the species is vulnerable to prolonged high temperature conditions, an issue that will be exacerbated by rising ocean temperatures and is particularly problematic on shallow coastal farms. In this study, we evaluated the response of adult farmed Atlantic surfclams to heat stress after juvenile exposure and the ability for heat tolerance to be passed to subsequent generations. We found that when juvenile Atlantic surfclams were exposed to prolonged lethal temperatures, the adult survivors withstood subsequent heat stress for significantly longer than individuals not exposed to lethal temperatures as juveniles. We also found that selective breeding enhanced heat tolerance in first-generation Atlantic surfclam progeny. Moreover, growth of the heat-selected progeny was not significantly different from that of control Atlantic surfclams. Although more research on this topic is necessary, this work suggests that selective breeding may be a viable strategy for enhancing survival of cultivated bivalves vulnerable to heat stress.