An analysis of the population genetics of restored Zostera marina plantings in Barnegat Bay, New Jersey

Within Barnegat Bay, New Jersey, eelgrass (Zostera marina) populations have declined by 62 % over the last 20 years. To better understand the consequences of this devastation, we have previously employed microsatellite DNA polymorphisms to analyze the population structure of Z. marina within Barnegat Bay, as well as along the eastern United States seaboard. We have restored populations of Z. marina in Barnegat Bay over the last 10 years to help assess the best planting conditions and ecotypes that might be used in long-term restoration strategies. In this study, we examined the genetic health of the restored populations compared to that of the donor eelgrass populations within the bay. Using microsatellites, we can identify which parental founding ecotypes survived the restoration process over multiple generations. The frequency of observed heterozygotes, although higher than in the natural populations, still indicates reduced levels of diversity and connectivity. The inbreeding frequency is high in the restored populations, but lower than what is seen in the native populations. All restored populations have effective population values >50, suggesting a high probability of survival in the short term.