Aquaculture 2025

March 6 - 10, 2025

New Orleans, Louisiana USA

Add To Calendar 07/03/2025 11:15:0007/03/2025 11:35:00America/ChicagoAquaculture 2025ESTUARINE LANDSCAPE SCALE ASSESSMENTS OF EELGRASS AND OYSTER AQUACULTURE AS HABITAT FOR NEKTON IN A US PACIFIC COAST ESTUARYBalcony KThe World Aquaculture Societyjohnc@was.orgfalseDD/MM/YYYYanrl65yqlzh3g1q0dme13067

ESTUARINE LANDSCAPE SCALE ASSESSMENTS OF EELGRASS AND OYSTER AQUACULTURE AS HABITAT FOR NEKTON IN A US PACIFIC COAST ESTUARY

Brett R Dumbauld*, Brooke McIntyre, David Beugli, Jennifer Ruesink, Fiona Boardman and Nathaniel Lewis

Agricultural Research Service, U.S. Dept. of Agriculture

Hatfield Marine Science Center

Newport, OR 97365

brett.dumbauld@usda.gov

 



Remote sensing has become a valuable tool for assessing interactions between shellfish aquaculture and submerged aquatic vegetation at the estuarine landscape scale. A geographic information system (GIS) with data layers for intertidal eelgrass (Zostera spp.) and active Pacific oyster (Crassostrea gigas) aquaculture distributions was first developed using orthoimagery in Willapa Bay, Washington in the mid-2000’s. These historical data served as a baseline for comparisons with updated GIS layers of eelgrass and active aquaculture distribution based on contemporary (2020) high resolution 4-band orthoimagery captured from fixed-wing aircraft during ideal low tide conditions. Contemporary orthoimagery and methodologies allowed for improved classification of eelgrass and delineation of aquaculture (via interpretation of visible evidence of culture, equipment, and physical use of the culture beds) which was then cross-checked and verified with the aquaculture industry (Figure 1). Overall, eelgrass coverage estimates in Willapa Bay declined from 5,938 ha in 2009 to 5,551 ha in 2020 (Table 1). Estimates of total oyster aquaculture were similar, while estimates of active oyster aquaculture increased from 2009 to 2020. This can largely be attributed to improved resolution of the delineation method and better definition of “active” culture boundaries. We present an example of how these new estimates can be used alongside a survey of habitat use by juvenile Dungeness crab and English sole to compare estuary-wide provision of low intertidal channel fringing habitat (<25m from channels) with that at higher tidal elevations.