Understanding the Hydrodynamic Effect of Oyster Farms in Shallow Water Estuarine Environments

Project Overview

GNE20-235
Project Type: Graduate Student
Funds awarded in 2020: $14,848.00
Projected End Date: 12/31/2021
Grant Recipient: University of New Hampshire
Region: Northeast
State: New Hampshire
Graduate Student:
Faculty Advisor:
Dr. Diane Foster
University of New Hampshire

Commodities

  • Animals: shellfish
  • Animal Products: other

Practices

  • Animal Production: aquaculture
  • Natural Resources/Environment: wetlands

    Proposal abstract:

    Oyster reefs provide a source of sustainable seafood, shoreline protection, and improved water quality (Weaver et al., 2017). Oyster farms have the potential to provide the same benefits to communities and ecosystems as their natural counterparts. To date, there has been little research focused on feedbacks between oysters, farming gear, and coastal environments in the Northeast Atlantic region. The goal of this study will be to improve the understanding of the relationship between oyster farms and coastal resiliency.

    From an oyster life cycle perspective, this project will examine the role of waves and currents on oyster growth, nutrient fluxes to and from oysters, and the structural stability of farming gear. From a coastal resiliency perspective, this project will address the role oyster farms play in preserving coastline environments (saltmarshes and beaches). Project questions will be addressed through a series of laboratory experiments where groups of oysters and different gear types will be exposed to full-scale mean (tidal/river flow) and oscillatory motions (waves). The project will leverage an ongoing collaboration and field study of shallow water oyster farms in Barnegat Bay, NJ.

    Key objectives for the lab experiments will be to develop empirical inferences regarding the feedback between oysters, farming gear, and the local flow field. Furthermore, the findings will be communicated to farmers through presentations and research briefs. The societal benefit of this project will be increased productivity of oyster farms and resiliency of our coastlines.

    Project objectives from proposal:

    In order to make realistic predictions about oyster farms and associated gear, field observations will be made under the scope of the existing USACE funding prior to the beginning of this project. These field observations will be used to characterize flow regimes at the oyster farm in Barnegat Bay, NJ. The following objectives for this project have been identified:

    Objective 1: Identify flow regimes in a range of oyster farm environments. Flow regimes (tidal currents, waves, steady mean flow) and flow magnitudes will be identified using the data from the USACE project in New Jersey and hydrodynamic models of the Great Bay estuary in New Hampshire. Extreme flow conditions will be determined based on the field conditions during data collection, testimony from farmers, weather reports, and from the hydrodynamic models of the Great Bay.

    Objective 2: Build model oyster gear. While gear types are widely varied, two main type of gear are used on oyster farms in the Northeast: floating mesh bags and bottom resting oyster cages with seeded mesh bags inside. There are also limited cases of farmers foregoing equipment and seeding the oysters directly on the bottom. Models of each case will be made using simulated oysters mimicking various life stages and gear deployment strategies. Simulated oysters will consist of silicone filled oyster shells.

    Objective 3: Quantify the feedback mechanisms. Using both observed (e.g. typical tidal flows) and extreme (e.g. storms) hydrodynamic regimes identified in Objective 1 and the model oysters and gear from Objective 2. The hydrodynamic effect of different deployment strategies will be quantified using PIV measurements made in the UNH Environmental Flows Water Tunnel (EFWT). This data will be used to determine the highest energy gear and individual oysters can withstand before being carried away and/or damaged and will confirm conditions under which shoreline protections may exist. Tests will also be done without gear, mimicking a natural oyster reef to compare to existing data.

    Objective 4: Develop deployment strategies. The results from Objective 3 will be used to develop empirical inferences between oyster farm characteristics and coastal resiliency. The study will provide farmers with feedback on the response of gear density and type to both typical and storm environments. This will provide critical information used in determining the ideal, maximum, and minimum depths for gear and farm operation.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.