Presentation on theme: "Ecosystem Services Provided by Shellfish Aquaculture Robert Rheault East Coast Shellfish Growers Association Moonstone Oysters Narragansett, RI"— Presentation transcript:
Ecosystem Services Provided by Shellfish Aquaculture Robert Rheault East Coast Shellfish Growers Association Moonstone Oysters Narragansett, RI Bob@moonstoneoysters.com
Army Corps Seeks Comment on Ecosystem Benefits and Impacts of Shellfish Aquaculture Very concerned about impacts to SAVs Do not differentiate between eelgrass and other SAVs that have fewer beneficial traits Do not appear to recognize that the desired ecosystem services from eelgrass are also provided by shellfish aquaculture Services from private commercial shellfish culture are similar to artificial reefs and restored habitats, but they do not cost the taxpayers millions!
EELGRASS Essential Fish Habitat Growth is light limited Thallus is weakened by excess nitrogen Cultured Shellfish populations can benefit eelgrass
Ecosystem Services from Shellfish Aquaculture Nutrients are removed when shellfish are harvested Shellfish feeding increases sedimentation rates which enhances bacterial denitrification Carbon deposited in shell is sequestered for decades Filter feeding improves water clarity and increases light penetration which helps eelgrass Shellfish and aquaculture gear provide habitat and support a diverse assemblage of juvenile fish Cultured shellfish release larvae into the environment
It only takes about 3,750 rapidly growing oysters to compensate for the nitrogenous wastes from one person leaching into the watershed.
Shellfish Filtration Reduces turbidity Improves light penetration Stimulates bacterial denitrification and reduces anoxia Nitrogen contained in shellfish tissue is removed from the system when the shellfish are harvested. If the shellfish are not harvested the nitrogen is released back into the water when the shellfish die and decay.
AQUACULTURE STRUCTURES PROVIDE HABITAT AND PROTECTION FOR LARVAL AND JUVENILE FISH AND INVERTEBRATES Improves the abundance and diversity of important marine species
Aquaculture structures Kilpatrick 2002 found more than ten times the abundance of fish and crustaceans in oyster gear vs eelgrass beds Species diversity was similar Species richness was similar Evenness was lower in aquaculture gear because of hyperdominance of mudcrabs
A 7.6cm market-size oyster contains 0.52 g N and 0.16 g P The combined effect of US eastern oyster aquaculture harvest directly removes 357 metric tons of nitrogen and 110 metric tons of phosphorus from the marine environment each year
Impacts of American Oyster Farming 357 metric tons of nitrogen removed 110 metric tons of phosphate removed Hundreds more tons of nutrients removed by burial or denitrification 51,559 tons of carbon sequestered in shell 1.7 x 10E15 larvae released each year 94 million cubic meters of water filtered daily Thousands of acres of oyster cultured grounds provide superior habitat
Army Corps Comment by November 27 For details visit www.ECSGA.org