R/AQ-14

Strategic focus area:

Description:

The soft-shell clam, (Mya arenaria, hereafter: Mya) a once important Maryland fishery, has declined to near insignificance for reasons believed to stem from certain epizootic pathogens and parasites and physiological stresses resulting from rising sea temperatures. More recently, commercial oyster aquaculture experienced significant growth resulting from genetic improvements. In 2022, the Morgan State University Patuxent Environmental and Aquatic Research Laboratory successfully demonstrated large-scale breeding of Maryland wild Mya within a shellfish hatchery setting, establishing a first milestone toward developing Mya as a potential aquaculture product. Subsequently the team used these Mya seed to investigate the suitability of several novel subtidal culture methods. One method has demonstrated outstanding Mya growth with average shell length close to the 2 inches market size at 12 months of age, of which 6 months was field culture. However, obstacles remain to commercial viability, such as summertime heat-induced mortality, since the Chesapeake is roughly the southern extent of the geographic range of this species. Our recent experiences with Mya culture suggests it may be feasible to minimize heat-induced mortality in aquaculture applications by scheduling the field grow-out period to avoid the peak of summertime heat as the animal matures. To this end, well-developed hatchery seed could be planted in the field after the summer peak, and subsequently harvested prior to the following summer peak. Furthermore, by developing a strain of Mya selected for heat tolerance, one could potentially extend the growing season to achieve larger yields at harvest, as well as help minimize crop risk posed by severe summer heat. In this project, we will employ genetic breeding approaches, marker assisted selection or genomic selection, to target heat tolerant trait in Mya, in order to begin the crafting of an animal tailored for use in the Maryland shellfish aquaculture industry.