Science Serving Maryland's Coasts


Development and Evaluation of Eco-Engineered Macroalgae and Shellfish Multi-Trophic Aquaculture Systems in the Chesapeake Bay

Principal Investigator: 

Ji Li

Start/End Year: 

2012 to 2014


University of Maryland, College Park

Co-Principal investigator: 

Daniel Terlizzi, Patrick Kangas, University of Maryland, College Park


Strategic focus area: 

Sustainable natural resources of coastal Maryland


OBJECTIVES: This project is to develop cultivation techniques to grow suitable seaweed, integrate to current oyster aquaculture, and evaluate the ecological impact and economic production. The detailed objectives are: 1) Identify suitable seaweed species for culture in the Chesapeake Bay, 2) Design a seaweed culture system compatible with shellfish culturing systems, 3) Obtain nutrient uptake data, growth rate and yield data, and estimate the nutrient removal efficiency, 4) Determine rates of nutrient release from oyster floats and determine the biomass of seaweed to utilize nutrients released, 5) Modify current ecosystem models for the seaweed-shellfish IMTA systems, and 6) Give an economic assessment of the economic impact of seaweed aquaculture.

METHODOLOGY 1) The cultivation system. Develop nursery technique for the selected seaweed species. Screens with pre-attachment treatment will be integrated into rafts for oyster aquaculture. 2) Environmental parameters. The ecological function of seaweeds (nutrient removal) will be evaluated by measurement of the environmental parameters (ambient nutrient, pH, DO etc.). The nutrient release by oysters will also be measured. 3) Growth Rate. The growth rate of both seaweeds and oysters will be measured. 4) Carbon and nutrient tissue analysis. Seaweeds will be analyzed for initial tissue C, N and P content to calculate productivity and removal rate. 5) Model simulation and prediction. Experiment results will be incorporated into an existing aquaculture model.

RATIONALE: Large, intensive commercial scale aquaculture may cause localized cultural eutrophication effects. Proposed work will develop new technologies of seaweed integrated multi-trophic aquaculture (IMTA) to removal extra nutrients, increase high value seaweed co-production, and support the sustainable development in the Chesapeake Bay region. Knowledge of the environmental impacts and modeling of IMTA will help guide the policy regarding resource management. By increasing the economic benefits to the aquaculture works from seaweed production, it may also increase the social acceptance of seaweed production in U.S.. The seaweed IMTA cultivation techniques also may be applied to finfish/shrimp aquaculture.


This section describes how this project has advanced scientific knowledge and/or made a difference in the lives of coastal residents, communities, and environments. Maryland Sea Grant has reported these details to the National Oceanic and Atmospheric Administration (NOAA), one of our funding sponsors.

Summary: Scientists worked to commercialize their research findings that growing seaweed (Gracilaria macroalgae) and oysters together in Chesapeake Bay can provide an economically valuable crop while improving the Chesapeake’s water quality. The seaweed can remove nutrients created by oyster cultivation from the water and be harvested for use as feedstock or biofuels. Researchers identified investors for the project and formed business plans to implement commercial production of Gracilaria in the estuary.

Relevance: Maryland state agencies have promoted oyster farming in the Chesapeake Bay because of its benefits to the economy and environment. Chesapeake Bay is facing the challenges of excess nutrients, eutrophication, and oxygen depletion. This research project confirmed that growing seaweed (Gracilaria macroalgae) together with oysters reduces the oyster aquaculture’s impact on the environment by removing excess nutrients, and the seaweed grown can be harvested for marketable products. Growing seaweed and oysters together would create jobs and generate additional income for oyster aquaculture businesses.

Response: Following up on their findings about growing seaweed and oysters together, a research team at the University of Maryland, College Park worked to establish what would be the first commercial macroalgae farm in the Mid-Atlantic region. They identified three investors to fund commercial farming of Gracilaria and oysters together. Project leaders worked with Hollywood Oyster Company, one of the largest oyster farms in the State of Maryland, to form a business plan.

Results: Researchers secured grant money to develop the commercial enterprise. Through Maryland Industrial Partnerships (MIPS) grants, the State of Maryland invested $90,000, Hollywood Oyster Co. invested $10,000, and Haiyuan Group, a seafood company in China, invested $10,000. In 2015, project leaders were working to secure a location for the commercial farming project to begin. Each acre cultivated is estimated to produce net revenue of $3,300 or more per year. The researchers expect to realize economies of scale and generate higher revenues by growing Gracilaria on additional acres. Project leaders identified another investor anticipated to invest $200,000 to fund the costs of labor and equipment. The researchers estimated that each acre of macroalgae farmed will annually remove 13,500 pounds of CO2, 300 pounds of nitrogen, and 20 pounds of phosphorus, thus helping to ease the problem of eutrophic waters in Chesapeake Bay.

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