Mussel Power Improving Water Quality and Engaging Coastal Communities Kristin Rasmussen October 31, 2011
An environmental management strategy by which nutrients are removed from an aquatic ecosystem through the harvest of enhanced biological production, including the aquaculture of suspension-feeding shellfish or algae.
Eutrophication - Excess nutrients lead to excess algae growth, which then decay and deprive the water of dissolved oxygen = fish kills and degraded habitat quality South Puget Sound Dissolved Oxygen Study, WA Dept. of Ecology, 2011
Septic systems Wastewater treatment plants Livestock Fertilizers Pet waste Sediment Alders
Sewage treatment Source control Extractive aquaculture technologies?
phytoplankton, other microbiota and detritus excretion and resuspension filter feeding shellfish removal through harvest excretion and burial in sediments
One harvested mussel contains: 0.8 1.2 % N and 0.06 0.08 % P Excess nutrients Mussel farming
Enhanced biomass Animal feed
Recycles nutrients Esp. effective for non-point sources of nutrients Useful in nutrient trading schemes Green farming Job creation Cost effective Relatively easy to move/remove Marketable goods Odd Lindahl, The Royal Academy of Sciences Kristinberg Marine Research Station, Sweden
Quartermaster Harbor Vashon Island Shallow, circulationrestricted bay Waste and stormwater inputs (40% of island), OSS Natural resource area Low Dissolved Oxygen
Model Output from EDFC Phase I South Puget Sound Study (S. Albertson), King County
Groundwater, 13% Atmospheric, 7% Sources of Dissolved Inorganic Nitrogen (DIN) in QMH Nearshore septics, 17% Stream inputs, 63% Benthic Flux?
Examine nutrient contribution of Puget Sound Measure benthic flux Additional monitoring of freshwater sources Identification of specific upland sources Atmosphere Septic systems Livestock Fertilizers Alders
Implement a demonstration aquaculture farm for a local species of bay mussel (Mytilus trossulus) Quantify the nitrogen removal services of mussels grown in QHM Prepare a conceptual nutrient-trading system Evaluate mussel production and market potential of products grown in the Harbor Engage communities and educate residents on nutrient source control
Photos: Leslie Brown, Vashon-Maury Island Beachcomber Photo: Puget Sound Restoration Fund Raft: 8x30 feet 75,000 mussels
137 5-foot long socks Raft designed for measuring: Water currents - pending Water quality conditions - pending Growth and biomass of the shellfish Marine nutrients (Nitrogen and Phosphorus) pending Associated organisms
Monthly length and weight measurements (n=210) Fouling type and weight Community assemblage Dry weight and N content Heavy metal, biotoxins/algae, viruses, bacterial concentrations Good growth rates but thick barnacle set
103% increase in fouling 4% decrease in mean mussel weight
High mortality (fouling, predation, design) Fouling decreased by 83% Breathing room: weight increased 27% (original) and 38% (new)
Growth: 27% in length and 116% in weight Most growth in late May through mid- June % Change Sd-Lgth Sd-Wt Fouling Set-Lgth Set-Wt 05/25/11 06/24/11 17 46 958 07/21/11 3 16 32 08/17/11 2-4 103 09/21/11 4 27-83 28 38 10/14/11 0 4-100 24 52 Tot Growth 27 116 59 110
Species May June Aug Sept Oct barnacles X X X X caprellids X X X nudibranchs X X nudibranch eggs X hydroids X X X X flat worms X X X ribbon worms X X X scale worms X X Nereis worms X shrimp X X isopods X sm sea stars X X sponge X bryozoan X moon jellies X X perch X Photos Photos Record/ photo Record Recalled
High mortality among original mussels (fouling, predation, system design) New recruitment Habitat creation
Vashon Island Growers Association 25 gallons of biomass Potential compost or chicken/pig feed.
QMH Nutrient Mitigation Study Sequestration and filtration data King County Nutrient Study Source and correlation with low DO data
100% N removal 80% N removal
Community engaged in construction Vashon High School students (biomass) Chautauqua Elementary School students (eutrophication/plankton education)
2 nd experiment in Spring 2012 Expand scope of project Expand study to other environments Examine potential to incorporate aquaculture sequestration technologies into local regulatory frameworks Engage local businesses and students directly in project research and outreach
Questions? Puget Sound Restoration Fund Brian Allen 590 Madison Ave. N. Bainbridge Island, WA 98110 Tel: 206.780.6947 Fax: 206.855.8820 Webpage: www.restorationfund.org Pacific Shellfish Institute Kristin Rasmussen 120 State Ave N.E. #1056 Olympia, WA 98501-8212 Tel: 360.754.2741 Fax: 360.754.2246 Webpage: www.pacshell.org