Preliminary assessment of benthic macrofauna community within intertidal mudflats, Lake Rudee, Virginia Beach, Virginia

The goal of this assessment was to evaluate the proposed dredging site at Lake Rudee to determine whether the natural resources within the proposed dredge area were of sufficient value that the permitting agency might require further data to be collected to aid in determining whether to grant a dredging permit or how much mitigation to require

From eFish to RecFish - Progress towards Developing an App that Engages Recreational Anglers as Community Scientists

The success of the Cornell Lab of Ornithology with eBird and its associated apps demonstrates the potential value in engaging recreational enthusiasts as community scientists through the use of a cell phone application (hereafter “app”). However, significant differences exist between the recreational angler community and the birding community making it necessary to further investigate the feasibility of engaging recreational anglers as community scientists using an app. The funds awarded through the VIMS Dean and Director’s Innovation Fund were used to: 1) assess the existing landscape of for-profit fishing apps and not-for-profit efforts to use recreational anglers as community scientists, 2) explore current app technologies for potential inclusion in a recreational fishing app, 3) explore potential external funding sources, and 4) determine a preliminary feature set for inclusion in an app for recreational anglers

Assessment of benthic macrofauna community within intertidal mudflats - Hurds Cove, Lynnhaven River, Virginia

A total of 30 samples were collected from eight locations in Hurds Cove, Lynnhaven River, VA. All samples were rinsed over a 500-μm mesh sieve and all material retained on the sieve was analyzed to determine benthic macrofaunal community identity, abundance and biomass. With the exception of one sample with relatively high biomass (50.68 g AFDW m-2) attributable to a single (Rangia cuneata), biomass across all locations was low, ranging from 0.16-0.67 g AFDW m-2. At five of the eight locations, all measurable biomass was contributed by polychaete worms. At the other three locations, polychaetes accounted for 45-57% of total biomass. At two locations, isopods contributed \u3e25% biomass and, at one location, decapod crustaceans accounted for 13.7% of the total biomass. Polychaetes and/or ostracods were the most abundant organisms in all locations. However, despite being abundant, ostracod biomass was below detection limits

Oyster reef ecosystem services: Macrofauna utilization of restored oyster reefs - Harris Creek, Maryland, USA

Oyster reefs provide habitat for a variety of macrofauna species. Our studies focused on the relationship between oyster tissue biomass density and reef-associated macrofauna biomass density. Studies were conducted in 2015-2017 and sites encompassed the majority of the area in which restoration activities were conducted with the Harris Creek Oyster Sanctuary in Maryland. Results presented in this report focus on: 1) interactions between oyster biomass density and season in determining macrofauna biomass, 2) responses of macrofauna to oyster biomass densities below “threshold” levels (0-14.9 g DW m-2) and between threshold and “target” levels (15-49.9 g DW m-2) defined in the success metrics for the Harris Creek restoration effort, 3) the role of tray-scale (0.1 m2), plot-scale (10 m2), and reef-scale oyster biomass density in determining associated macrofauna biomass, and 4) larger scale patterns in macrofauna biomass density within the creek

Environmental and Ecological Benefits and Impacts of Oyster Aquaculture Chesapeake Bay, Virginia, USA

To better quantify the ecological benefits and impacts of oyster aquaculture, we sampled water quality, sediment quality, benthic macrofaunal communities and oysters at four oyster aquaculture sites located on the western shore of Chesapeake Bay in Virginia, USA. At each site, we collected samples from within the footprint of the aquaculture cages and from nearby areas with similar physical and environmental conditions but far enough away to be minimally influenced by aquaculture operations. Data collected from the water column included chlorophyll concentrations, turbidity, pH, dissolved oxygen concentrations, light attenuation, particle concentration, median particle size, total suspended solids and their organic content, and dissolved nutrient concentrations. Sediment and macrofauna community data collected included sediment grain size and organic content and macrofauna identity, abundance, biomass and species richness. In addition to assessing the potential impacts of oyster aquaculture on the water column and benthos, we also assessed differences in the oysters harvested Environmental and ecological benefits and impacts of oyster aquaculture at each site and estimated the total amount of nitrogen and phosphorus harvested at each site. Differences in water quality, sediment quality, and macrofauna community structure between areas within and outside the farm footprint were rare and of small magnitude and varying direction (i.e. negative versus positive impact) when they did occur. Aquaculture sites varied by an order of magnitude in size, annual harvest and harvest per unit area. They also varied by an order of magnitude in the total amount of nitrogen (N) and phosphorus (P) harvested per unit area. In contrast to the negative environmental impacts associated with other forms of animal protein production for human consumption, oyster harvest from aquaculture sites studied here resulted in the removal of 21-372 lbs. of N and 3-49lbs of P per farm per year

Minimal effects of oyster aquaculture on local water quality: Examples from southern Chesapeake Bay

As the oyster aquaculture industry grows and becomes incorporated into management practices, it is important to understand its effects on local environments. This study investigated how water quality and hydrodynamics varied among farms as well as inside versus outside the extent of caged grow-out areas located in southern Chesapeake Bay. Current speed and water quality variables (chlorophyll-a fluorescence, turbidity, and dissolved oxygen) were measured along multiple transects within and adjacent to four oyster farms during two seasons. At the scale of individual aquaculture sites, we were able to detect statistically significant differences in current speed and water quality variables between the areas inside and outside the farms. However, the magnitudes of the water quality differences were minor. Differences between sites and between seasons for water quality variables were typically an order of magnitude greater than those observed within each site (i.e. inside and outside the farm footprint). The relatively small effect of the presence of oysters on water quality is likely attributable to a combination of high background variability, relatively high flushing rates, relatively low oyster density, and small farm footprints. Minimal impacts overall suggest that low-density oyster farms located in adequately-flushed areas are unlikely to negatively impact local water quality. Associated datafiles available at: https://doi.org/10.25773/wwva-tz1

A Data Repository for Minimal Effects of Oyster Aquaculture on Water Quality: Examples from Southern Chesapeake Bay

The objective of this study was to quantify the effects of oyster aquaculture on water quality, sediment quality, and hydrodynamics at select sites in southern Chesapeake Bay. To this end, information was gathered over the course of approximately one year from February 2017 to October 2017 at four operating commercial farms. Farms were sampled during spring, summer, and fall seasons during times of oyster filtration activity when temperatures were greater than 10oC. Aquaculture sites differed in environmental setting, in terms of their exposure to waves and resulting sediment characteristics. Sites had mesohaline salinities (ranging from 15-22 psu) and mean water depths of ~1 m (ranging from 0.5 to 2 m depending on distance from shore and tidal stage). Site characterization was conducted at each oyster farm using standard sedimentological measurements with a PONAR grab to map sediment characteristics throughout the extent of each oyster farm and surrounding area. Following site characterization, hydrographic, water clarity, and water quality data were collected using high frequency spatial water quality mapping of transects on a moving vessel and an instrumented profiler at discrete point samples. On high frequency spatial water quality mapping (transect) cruises, the vessel was driven along 10-30 transects including approximately half inside and half outside the extent of cages while vessel-mounted instruments sampled continuously. On discrete point sample (instrumented profiler) cruises, data were collected at five designated stations along a central transect of the farms with three stations within the extent of cages and two stations outside. The two smallest oyster farms were sampled only during Summer 2017. Two of the larger oyster farms were sampled during Summer and Fall 2017. Additionally, during Summer 2017 at Windmill Point, a stationary upward facing acoustic Doppler profiler collected data over one month

Integrated assessment of oyster reef ecosystem services: Quantifying Denitrification Rates and Nutrient Fluxes

Measurements of nutrient exchange were made in restored oyster reefs and creek sediments in 2014 and 2015 in Harris Creek, Maryland, USA. Rates of ammonium, nitrate and di-nitrogen fluxes were much higher in reef environments than in sediments, and rates of oxygen uptake reflected high inputs of biodeposits. The rate of denitrification was related to oyster biomass and oyster numbers. The shallow nature of the restoration allows light to reach the bottom and benthic microalgal photosynthesis affects the net nutrient exchange with the bottom. After several years, oyster restoration has increased denitrification in Harris Creek, though observations in mature upper Choptank restored reefs are higher. The trajectory of increase of the nutrient ecosystem services is positive and will be followed over time

An updated model for estimating the TMDL-related benefits of oyster reef restoration Harris Creek, Maryland, USA

In 2014, a user-friendly, web-accessible model was developed that allowed restoration practitioners and resource managers to easily estimate the TMDLrelated benefits of oyster reef (Crassostrea virginica) restoration per unit area, run restoration scenarios in Harris Creek, MD to optimize restoration planning and implementation, and calculate the benefits of the chosen plan. The model was rooted in scientifically defensible data and was readily transferrable to systems throughout the Chesapeake Bay and Eastern Shore. The model operated in five vertically well-mixed boxes along the main axis of the creek. Exchanges among creeks were computed using a tidal prism approach and were compared to exchanges provided from a high resolution 3D hydrodynamic model. Watershed inputs for the model were obtained for the Harris Creek sub-watershed from the Phase V Chesapeake Bay Program Watershed Model. The base model simulated daily concentrations over an annual cycle of chlorophyll-a, dissolved inorganic nitrogen (N) and phosphorus (P), dissolved oxygen, total suspended solids, the biomass of benthic microalgae, and the water column and sediment pools of labile organic carbon (C) and associated N and P. Water quality data for model forcing and calibration were obtained from the Chesapeake Bay Program, the Choptank Riverkeeper, the University of Maryland Center for Environmental Science, and the Maryland Department of Natural Resources. An oyster sub-model was coupled to this base model to compute the volume of water filtered, removal of phytoplankton, suspended solids, and associated nutrients via filtration, recycling of nutrients and consumption of oxygen by oyster respiration, production of feces, N and P accumulation in oyster tissues and shell, oyster-enhanced denitrification, and N and P burial associated with restored reefs. The completed model was served online and operated through a web browser, enabling users to conduct scenario analysis by entering box-specific values for acres restored, restored oyster density, and restored oyster size, as well as the economic value of associated N and P removal. The updated model incorporates all aspects of the previous model but replaces oyster related data collected outside Harris Creek with site-specific data, and now includes restored oyster populations and water quality data through 2016. It also incorporates the impacts of two common, reef-associated filter feeding organisms: the hooked mussel Ischadium recurvum and the sea squirt Molgula manhattensis. Additional data collected in Harris Creek and incorporated into the model include: biomass of benthic microalgae, biogeochemical fluxes in relation to oyster biomass, and the biomass density and distribution of the dominant non-oyster reef filter feeders (I. recurvum, and M. manhattensis). The revised model incorporates an improved estimate of annual oyster growth, uses an improved method for estimating N and P sequestered in tissues and shells, and accounts for the prerestoration oyster population in Harris Creek. The model also incorporates data on the filtration capacity of I. recurvum and M. manhattensis in relation to C. virginica collected as part of a previous study (not in Harris Creek) by Kellogg and Newell (unpublished data)