This project will invest in small-scale restoration within the Nanticoke River oyster sanctuary. The restoration will consist of hatchery spat-on-shell plantings.
In 2022, DNR planted spat-on-shell using small-scale restoration funds on two bars within the Nanticoke Sanctuary, Hill Shoals and Outer Hole. A total of 20.7 acres were planted with a total of 69.43 million spat-on-shell.
DNR periodically monitors sanctuaries including the Nanticoke River to assess the oyster population. In 2023, DNR did a patent tong survey to evaluate the oyster population of Nanticoke Sanctuary. The sites planted in 2022 were sampled in the survey and showed healthy oysters from the planting. The average density of live oysters sampled throughout the Nanticoke River was 29.2 oysters per m2. The density of market size oysters was greater than the density of spat and small oysters (19.2, 4.6, and 5.4 respectively). Thirty-nine percent of the samples collected had no live oysters. These results show an increase in the oyster population in the Nanticoke Sanctuary in the five years since the previous patent tong survey performed in 2018. Future planting plans will be evaluated based on the most recent patent tong data collected.
Existing Conditions
The sanctuary within the Nanticoke River was established in 2010 and encompasses 16,600 surface acres. The Nanticoke River sanctuary is considered a low salinity region (<12ppt). The mean bottom water dissolved oxygen level within the Nanticoke River is generally above
5 mg/l. These levels are suitable for oyster growth and survival. There is no reported acreage of submerged aquatic vegetation (SAV) habitat in the Nanticoke River sanctuary, so no oyster bar acreage coincides with SAV. A portion of the sanctuary is classified as a restricted by the Maryland Department of the Environment (2018) due to potential contamination of shellfish by fecal coliform and other bacteria.
The Coastal Marine Ecological Classification Standards (CMECS) bottom characterization from data collected during the 1970-80’s Bay Bottom Survey and a 2011 side scan sonar survey conducted by Maryland Geological Survey was used to identify areas of historic oyster bars that have substrate other than mud.
Population data from a patent tong survey conducted by the DNR- Shellfish Division in May 2018 was used to understand the pre-restoration population. The average density of live oysters sampled throughout the Nanticoke River was 10.5 ± 1.49 oysters per m2 (mean ± standard error). The density of market size oysters was greater than the density of spat and small size oysters (6.77 ± 0.96, 1.31 ± 0.24 and 2.41 ± 0.39 respectively). Fifty-one percent of the samples collected had no live oysters.
Potential Oyster Restoration Sites
Green: These bars have some shell and low oyster densities. These would be the areas considered first to receive restoration efforts.
Yellow: These bars have some shell and low oyster densities and are within the MDE restricted shellfish harvesting area. This area would be considered the second priority to receive restoration efforts.
Orange: These bars are those that have little to no oyster densities but, have suitable bottom habitat. These bars would be the third priority to receive restoration efforts.
Red: These bars are those that exhibited reasonable oyster densities and have some shell. These bars would be the fourth priority to receive restoration efforts since these bars may already be restored naturally.
Purple: These bars do not have suitable bottom habitat and would require substrate. This is beyond the scope of our current plan due to funding limitations.
Black: These bars will not be considered for restoration. One of the bars is within a lease area and the other two are either a Fall Survey key bar or disease bar.
