University of Oregon

South Slough: Potential Projects

Bree Yednock croppedThe Science team at the South Slough National Estuarine Research Reserve (SSNERR); Charleston, OR includes studies of ocean acidification, water quality, saltmarsh ecology, estuarine fish and invertebrate ecology, population genetics/genomics, and non-native species. (1) In recent years, non-native eelgrass (Zostera japonica) has become established in estuaries across the Pacific Northwest. While eelgrasses are known for their importance in supporting diverse assemblages of epifauna and infauna (Lee et al. 2001), and for providing critical rearing habitat for estuarine-dependent fishes and invertebrates (Hosack et al. 2006), it is not known if Z. japonica provides the same ecological benefits as the native eelgrass, Z. marina. An example student project related to this question would be to compare the abundance and diversity of epifauna and infauna associated with eelgrass beds that are comprised exclusively of either Z. japonica or Z. marina and in beds where the two species co-occur. This project would involve collecting eelgrass shoots (with associated epifauna) and sediment cores in each of the three types of eelgrass beds, as well as measuring eelgrass bed metrics (e.g. shoot density, shoot area, and biomass) to make comparisons between the habitat structure provided by each kind of eelgrass bed. 2) An additional project would be investigating the potential for Z. japonica to impact the nursery function of estuarine habitats. For example, unstructured littoral habitats, such as tidal flats, constitute important foraging areas for subadult Dungeness crabs (Cancer magister) because they support increased foraging efficiency compared to eelgrass beds and provide critical biomass needed to meet daily energetic requirements of juvenile crabs (Holsman et al. 2003; Holsman et al. 2006). When unstructured estuarine tidal flats become converted to structured habitat by Z. japonica, the nursery function of the area may become reduced. A student investigation into prey availability and foraging behavior of juvenile crabs in newly established non-native eelgrass beds could address this hypothesis and provide information on the potential for Z. japonica to reduce the contribution of estuarine-reared juveniles to the Pacific Dungeness fishery (Armstrong et al. 2003). 3) The invasive European green crabs (Carcinus maenas) were abundant in the Coos Bay Estuary in 2016-2017 due to strong recruitment (Yamada et al. 2017) and were frequently trapped in eelgrass and mudflat habitats where they co-occur with native Dungeness crabs (Cancer magister).  This research focus would be addressing potential impacts on changes in density, geographic extent, and diversity of epifauna and infauna of eelgrass beds relative to green crab densities.   Data collected in this project will be important for informing impacts of green crab to the nursery function of the estuary and to inform future control strategies for the estuary. 4) The South Slough National Estuarine Research Reserve (Reserve) monitors tidal wetland response to water level and other water column parameters in order to understand long term effects of sea-level rise on coastal habitats.  For this research project, a variety of data are collected including vegetation distribution and abundance, sediment dynamics i.e. accretion/erosion rates, groundwater level, along with long-term water quality, nutrient and weather data. Depending on the student’s interests and background, potential research questions to explore might be 1) how will tidal marsh vegetation communities (plant characteristics measured) located along an estuarine gradient, respond differently to changes in sea level? 2)  How do water table dynamics and groundwater levels change along the estuarine gradient in response to changes in sea level? or 3) What are relationships between vegetation patterns and water quality parameters i.e. salinity, turbidity?


Armstrong, D.A., Rooper, C. and Gunderson, D., 2003. Estuarine production of juvenile Dungeness crab (Cancer magister) and contribution to the Oregon-Washington coastal fishery. Estuaries26(4), pp.1174-1188.

Holsman, K.K., Armstrong, D.A., Beauchamp, D.A. and Ruesink, J.L., 2003. The necessity for intertidal foraging by estuarine populations of subadult Dungeness crab, Cancer magister: Evidence from a bioenergetics model. Estuaries26(4), pp.1155-1173.

Holsman, K.K., McDonald, P.S. and Armstrong, D.A., 2006. Intertidal migration and habitat use by subadult Dungeness crab Cancer magister in a NE Pacific estuary. Marine Ecology Progress Series308, pp.183-195.

Hosack, G.R., Dumbauld, B.R., Ruesink, J.L. and Armstrong, D.A., 2006. Habitat associations of estuarine species: comparisons of intertidal mudflat, seagrass (Zostera marina), and oyster (Crassostrea gigas) habitats. Estuaries and Coasts29(6), pp.1150-1160.

Lee, S.Y., Fong, C.W. and Wu, R.S.S., 2001. The effects of seagrass (Zostera japonica) canopy structure on associated fauna: a study using artificial seagrass units and sampling of natural beds. Journal of Experimental Marine Biology and Ecology259(1), pp.23-50.

Yamada, S. B., J. A. Prickett, B. Yednock, J. Indivero, E. Alvarado, and C. Geirerman. 2017. Status of the European Green Crab, Carcinus maenas, in Oregon and Washington Estuaries in 2017.  Report to Oregon Department of Fish and Wildlife.