Shellfish environmental benefits

Oysters are keystone species because they have a disproportionately large impact on the natural environment and other species in an ecosystem.
Oysters are also ecosystem engineers because they significantly modify and create new habitat for other species by forming reefs. A conservative economic evaluation estimated oyster reef benefits at 5,500-$99,000/hectare/year, excluding the value of oyster harvesting.
The nooks and crannies of shellfish beds create structure and habitat for invertebrates and juvenile fish, which are a food source for predatory fish and other marine species. Healthy shellfish populations help to support finfish populations. Watch how oyster reefs form and organisms use the reefs.
Shellfish help to minimize the impacts of climate change. Climate change will cause shoreline erosion, increased storm intensity and frequency, and coastal flooding, among many other impacts. Shellfish beds stabilize sediments, helping to protect the shoreline from erosion and storms. Additionally, oyster reefs can sequester carbon, and protect surrounding habitats like salt marshes from erosion, aiding carbon sequestration in these habitats.

Shellfish are filter feeders, which remove particles and nutrients from the water column through their natural feeding process. Market-sized oysters can filter up to 45 gallons/day!
- Shellfish feed on phytoplankton, but can also accumulate marine biotoxins; chemical contaminants; and pathogenic microorganisms, such as bacteria and viruses; effectively removing them from the water column.
- Shellfish help control harmful algal blooms, such as red tide, by removing algal cells before they accumulate to harmful levels.
- Improved water quality makes the environment more suitable for vegetation and organisms that require high water clarity, such as eelgrass.

Benefits of Shellfish Aquaculture

Shellfish aquaculture is a sustainable and green industry. Read more about seafood sustainability and how aquaculture supports sustainability through NOAA.
Sustainable aquaculture helps to reduce harvesting pressure, and can even reduce disease impacts, on wild populations.
Aquaculture gear can also have beneficial ecological impacts by creating structure and habitat. Photos from the NOAA Milford Lab GoPro Aquaculture Project are shown below (all rights reserved). Watch how different Long Island Sound fish species interact with aquaculture gear.
Excessive nutrient loading can result in eutrophication, which can deplete areas of oxygen or cause harmful algal blooms. Shellfish naturally remove nitrogen and other nutrients from the environment. Using the NOAA Nutrient Removal Calculator, approximately 6,966 pounds of nitrogen is naturally removed annually by oysters commercially harvested in Connecticut. This is equivalent to 7,113,000 square feet of lawns fertilized, and does not include the benefits of all shellfish in Long Island Sound as there are naturally-occurring populations and aquaculture oysters remain in the water for multiple years before they are harvested.