Abstract
In addition to suitable substrate and physical conditions, successful oyster recruitment requires an adequate supply of planktonic larvae from local and remote source areas, followed by the subsequent survival and growth of early post-settlement stages. Recruitment limitation arises when the stock size is constrained below some threshold density by the supply of larvae. Above the threshold density, stock size should reflect post-settlement processes such as growth and predation more than larval supply rates. Low abundances of adult oysters in some areas of Mississippi Sound in the summer of 2018 were likely caused by the combined effects of multiple stressors. Thus in 2018, local recruitment was potentially limited within certain areas of Mississippi Sound. Despite low abundances of adults in some areas, spat settlement appeared sufficient to support oyster recruitment throughout western Mississippi Sound in 2018. However, subsequent sustained freshwater inflow for 122 d in 2019 extensively devastated adult oyster stocks, apparently even including more remote sources of larval supply. Consequently, the recruitment limitation threshold was exceeded, as spat settlement was effectively eliminated in Mississippi Sound during the oyster spawning season of 2019. Thus, recruitment limitation now presents a major challenge to oyster restoration efforts in Mississippi.
