Glenn VanBlaricom, University of Washington, School of Aquatic and Fishery Sciences
Chris Harvey, NOAA, Northwest Fisheries Science Center
P. Sean McDonald, University of Washington, School of Aquatic and Fishery Sciences
Uncertainty about the wide ecosystem effects of large-scale, high-density geoduck aquaculture has hindered expansion and additional tideland leasing. This project will integrate five years’ data from aquaculture sites and reference beaches into a published food-web model for Central Puget Sound. With guidance from a multi-stakeholder advisory panel, it will test an incrementally varied spectrum of aquaculture scenarios, including geoduck densities surpassing any now projected, and their potential effects on habitat, fisheries, mortality, and predator–prey interactions. Findings will guide recommendations for future aquaculture development.
Washington Sea Grant-funded researchers investigated the effects of expanding intertidal geoduck culture on the Central Puget Sound ecosystem. They incorporated key predator–prey relationships into a robust food-web model and worked with a comprehensive panel of stakeholders to identify important linkages for inclusion when assessing management scenarios.
Initial modeling suggests that effects are most pronounced at farm sites but can ripple throughout the food web when farming expands dramatically. This may adversely affect flatfish, predatory snails and small crustaceans directly and more mobile species such as eagles, herons and salmon indirectly. Shorebirds, crabs, surf perch and some other organisms may benefit directly or indirectly from culture-driven habitat changes. Bottomfish, small crustaceans, and flatfish may be useful as indicator species. Regulators immediately began incorporating the model in their analyses: the U.S. Army Corps of Engineers cited it in its Programmatic Biological Assessment of Shellfish Activities in Washington State Inland Waters, and other agencies will do likewise. “We found it extremely helpful and informative,” said one Corps scientist. “It’s the first time someone has done this modeling.”