Nisqually Delta eelgrass
In Washington State’s Puget Sound, eelgrass—a marine plant in the shallow waters— serves as a food source, nursery, and haven for juvenile salmon, forage fish, and many other species. It also plays and important role in the ecosystem as it filters sediments and nutrients, improves water quality, and protects shorelines from erosion. However, the extent to which these eelgrass meadows in river deltas provide critical rearing habitat for local estuarine fishes, especially out‐migrating juvenile salmon, is not well understood. Further, delta eelgrass has been impacted by diking and river channelization with unknown consequences for fish.
USGS is conducting research in the Puget Sound as part of the Coastal Habitats in Puget Sound program, an interdisciplinary collaboration to coordinate, integrate, and link USGS studies with the Puget Sound Nearshore Ecosystem Restoration Project. In an article published in Marine and Coastal Fisheries, USGS scientists from Western Fisheries Research Center (WFRC) and Pacific Coastal and Marine Science Center investigated how diking and river channelization potentially influenced eelgrass use by fish. They found that Chinook salmon were more abundant in eelgrass than in unvegetated habitat in summer months and in the delta region. They also found that abundances of Pacific herring and Shiner perch were consistently several-fold higher in eelgrass than in unvegetated habitat. Results indicated that conservation and restoration of delta eelgrass would benefit these species and help to identify the settings in which these actions would be most beneficial. This information could be useful for natural resource managers making decisions about the nearshore ecosystem.
Now, in a fortunate collaboration between WFRC and the USGS Geospatial Science and Cyber Innovation Branch (GSCI) of the Texas Water Science Center, this information can be viewed using an interactive visualization tool. Sachin Shah, a hydrologist with GSCI, is part of an interdisciplinary team intersecting science and technology to deliver information to the public and stakeholders. Shah is currently stationed at WFRC’s Seattle Center, creating an opportunity for WFRC to draw on his expertise and tools to explore fisheries questions and conduct analysis in different ways. Working together, WFRC scientist Steve Rubin and Sachin Shah created a website with interactive visualizations of the previous study, looking at spatiotemporal variation in abundance and body size of juvenile Chinook salmon and three forage fish species in relation to eelgrass. The website and accompanying graphics allow users to interact with data concerning the abundance and body size of Chinook salmon, and three forage fish (Pacific herring, surf smelt, and Shiner perch) in relation to eelgrass presence or absence and water column properties. The data visualizations take into account environmental effects on the distribution and abundance of these species, the application also includes temperature, salinity, depth and supporting data layers that allow end-users to consider how diking and river channelization potentially influenced eelgrass use by these fish.
“This collaboration opened my eyes to new, innovative ways to present data.” said Rubin, “The interactivity of the tool allows customized data exploration which in this case we hope will enhance understanding of how juvenile salmon and forage fishes use eelgrass on river deltas and contribute to decisions relevant to protection of these species and habitats.”
To learn more about the tool or study, check out the website at https://webapps.usgs.gov/pugetsound/eelgrass .
Newsletter Author: Rachel Reagan
USGS Study Describes Movement Patterns of Adult Sockeye Salmon in the Reach Between Roza Dam and Cle Elum Dam on the Yakima River, Washington: Scientists from the WFRC recently completed a report on movement patterns of adult sockeye salmon in the upper Yakima River, Washington. Adult sockeye salmon were tagged with radio transmitters at Roza Dam during 2018 and monitored as they moved upstream to Cle Elum Dam. The Bureau of Reclamation is working to provide volitional fish passage at Cle Elum Dam and provided funding for the study to determine if fish could move upstream from Roza Dam and successfully arrive in the Cle Elum Dam tailrace. Under current conditions adult salmon and steelhead are collected at Roza Dam and transported to upstream areas where they are released. The study found that all the radio-tagged sockeye salmon (n=20) arrived at Cle Elum Dam with a median travel time of 17 d.
Kock, T.J., S.D. Evans, B.K. Ekstrom, and A.C. Hansen. 2019. Adult sockeye salmon (Oncorhynchus nerka) behavior and movement from Roza Dam to Cle Elum Dam, Washington, 2018: U.S. Geological Survey Open-File Report 2019-1053, 8 p.
New Publication Examines Effectiveness of Fish Screens on Protecting Lampreys: Thousands of screened water diversions throughout the Columbia River Basin are sources of entrainment (unintended diversion into unsafe passage routes), injury and mortality for a range of fish species. Screening criteria have been developed to reduce and mitigate these effects, but potential effects of these screens on juvenile and larval lampreys is largely unknown. In a recent USGS report, prepared in cooperation with the Washington Department of Fish and Wildlife, McNary Fisheries Compensation Committee, and Yakama Nation Fisheries, scientists compare entrainment, impingement and injury rates of larval lamprey (ammocoetes) exposed to two screen angles. Scientists found some advantages of a 12-degree screen compared to a 20-degree screen for protecting lamprey, suggesting that screens installed more parallel to flow might warrant further testing.
Liedtke, T.L., D.J. Didricksen, L.K. Weiland, J.A. Ragala, and R. Lampman. 2019. Effectiveness of fish screens in protecting lamprey (Entosphenus and Lampetra spp.) Ammocoetes – Pilot testing of variable screen angle. U.S. Geological Survey Open-File Report 2019-1044.