Geochemical and Ecological Consequences of Disturbances Associated with Geoduck Aquaculture Operations in Washington
Glenn VanBlaricom, David Armstrong and Tim Essington, School of Aquatic and Fishery Sciences, University of Washington, and Jeffrey Cornwell and Roger Newell, Horn Point Marine Laboratories, University of Maryland
R/GD-1a and R/GD-1b
In recent years, there has been substantial public and scientific interest in the possible ecological effects of expanding geoduck aquaculture operations in Puget Sound. As part of a large-scale multidisciplinary study, researchers will be addressing several of the most pressing issues regarding the effects of geoduck aquaculture on the Puget Sound ecosystem. This is a multi-year, comprehensive effort that combines the extensive knowledge and capabilities of local university marine scientists working in Puget Sound with the substantial expertise of sediment geochemists from one of the East Coast’s leading environmental institutions.
Current geoduck culture operations involve three fairly distinct phases on Puget Sound beaches. The first is out-planting of juvenile hatchery-reared clams and placement of structures meant to protect the clams. The second phase is removal of the protective structures after one to two years, at which point young clams are established and no longer at risk from predators. The third phase is harvest of cultured clams, which occurs five to seven years after initial out-planting. For the most part, public and scientific concern centers on the effects of protective structures and harvest techniques on the natural dynamics of resident ecosystems. At present, however, there is little scientific information available to aid managers charged with regulating geoduck aquaculture operations. The collaborative effort seeks to answer questions at the forefront of current interest using an ecosystem-level approach, including:
- What are the effects of aquaculture structures on communities of plants and animals living in or on Puget Sound beaches?
- Do structures change the behaviors or movements of important fish or shellfish (e.g., salmon, Dungeness crab)?
- How does disturbance during geoduck harvesting affect communities of plants and animals and subsequent recovery of the ecosystem?
- How does disturbance during harvesting alter the physical and chemical properties of Puget Sound beaches?
Throughout the culture cycle, researchers will specifically investigate ecosystem-level effects, including patterns of recovery following punctuated culture activities, like installing structures or harvesting clams, for a diverse array of resident and mobile organisms. They will also assess modifications of physical and chemical attributes of the beach environment in order to better understand the initial effects and rates of recovery of plants and animals affected by aquaculture operations.
Most importantly, the collaborative effort is designed to provide results that will inform decisions regarding the costs and benefits of expanded aquaculture operations in Puget Sound. The novel approach outlined by the research team compares periodic disturbances associated with culture activities to naturally occurring background levels of disturbance, such as storms, and will provide the scientific foundation for policy decisions that must balance the needs and concerns of shellfish growers, environmental groups and property owners.
Work to Date
The researchers are anxious to begin collecting data and have already taken the first steps in planning upcoming research activities. They met with shellfish growers in late March, 2008, to identify candidate study sites in northern, central and southern Puget Sound and plan to visit the areas in late May, 2008. Once the suitability of these locations has been assessed, scientific investigations will begin in earnest.
Updated May 22 2008