Restoration of a Mid-Atlantic Coastal Bay Scallop Population (Argopecten irradians)

<title>Abstract</title> Bay scallops (Argopecten irradians) once flourished in the eelgrass (Zostera marina) meadows of the Virginia coastal bays. Eelgrass wasting disease led to meadow declines, and both eelgrass and scallops were lost after a 1933 hurricane. The Virginia Institute of Marine Science (VIMS) led a successful seagrass restoration effort starting in 1997, expanding at 240 ha per year since 2007, and covering over 4,800 ha in 2025. From 2009-2025, we have been attempting to restore bay scallops to these grass beds. Bay scallops were brought from North Carolina to the VIMS Eastern Shore Laboratory (VIMS ESL) in Wachapreague, VA for brood stock. Progeny were released to the eelgrass beds and held in spawning cages. Annual census data have documented low and fluctuating scallop densities from 2012-2018, and continued exponential growth from 2019-2025 with a current specific growth rate of m = 0.473 year-1 and a population doubling time of 1.47 years. The carrying capacity of the system for the new Virginian bay scallop population remains unknown with the population still in the exponential growth phase. In 2025, we documented an average density of 0.114 scallops m-2. However, the spatial extent of the eelgrass bed is not evenly utilized by the scallops, with a 2025 maximum recorded local density within 50 m-2 sampling stations of 0.52 scallops m-2. Aggregation within the population was anticipated as necessary for reproductive success and was observed in population data with increasing density. The restoration of Virginia bay scallops represents a significant societal and ecological achievement.