Through a subcontract with the University of Washington, PSI is receiving NOAA Marine Aquaculture Program funding to develop environmentally and economically sound methods to reduce geoduck mortalities. This research meets the high priority 2015 goal 3.2, "Ecological impacts (positive and negative) associated with shellfish growing and harvesting, should be documented, understood, and incorporated into the shellfish industry Environmental Management System (EMS). "
Task 1: Test methods to exclude predators and minimize mortalities of juvenile geoduck.
PSI is working with growers in Eld and Case Inlets to assess the performance of a suite of alternative predator protection methods in pilot scale field plots. Test methods include broad area mesh cover, flexible mesh tubes, mesh tunnels, a variety of biodegradable materials, and planting large seed without predator protection. Most methods require field testing and evaluation for efficacy and performance. Plots range in size from 4 to 400 m2 and are designed to provide side-by-side comparative assessment of alternative methods versus traditional PVC pipe methods.
Task 2: Assess environmental effects of predator exclusion methods on gross biomass, salmonid prey species and sediments.
To avoid an overlap with environmental sampling currently underway by other groups, PSI is focusing on alternative predator protection methods, and is conducting limited comparative epibenthic sampling for meiofauna (including prey organisms of juvenile salmonids and other finfish) on both traditional and alternative predator protection sites.
Task 3: Evaluate filtration parameters in farmed geoducks in situ.
Geoduck feeding activity is directly measured with a field flume or Benthic Ecosystem Tunnel (BEST) and quantitative collection of adjacent biodeposits. The tunnel is outfitted with instrumentation to enable continuous measurements of seston flux, current velocities and direction, in-vivo fluorescence, turbidity and oxygen at the upstream and downstream ends of the tunnel, and water samples for marine phytoplankton. Data will be used to evaluate geoduck filtration and calibrate farm-scale seston depletion models.