Western Fisheries Science News, February 2019 | Issue 7.2
White Sturgeon, found in large river systems along the west coast, are the largest freshwater fish in North America. This primitive looking fish—with bony plates running along its back and a long flat snout, and whisker-like barbels—can reach lengths of 20 feet and live over 100 years. While some populations of White Sturgeon migrate between ocean and freshwater, some also are landlocked and don’t migrate at all. White sturgeon provide commercial and recreational fisheries, are an ecological cornerstone, and are culturally important to regional Native American Tribes in the Pacific Northwest.
Overharvest and vast habitat changes caused by construction of dams and reservoirs and resultant river regulation have affected White Sturgeon populations throughout their range. Specifically, dams have restricted the movement of White Sturgeon in many rivers and altered their spawning and rearing habitats due to changes in hydraulics and substrate composition. In the Columbia River Basin, White Sturgeon recruitment (i.e., sturgeons surviving their first year) has varying levels of success, depending on the reach and habitat conditions. Some river reaches have virtually no recruitment while others have consistent recruitment year after year. Areas of the Columbia River with severely depleted White Sturgeon populations rarely document wild juvenile fish, suggesting that there is high mortality during egg incubation, larval or early juvenile stages. The cause of this early mortality likely varies among areas and is due to a variety of physical and biological factors, but substrate quality has been identified as a primary determinant of recruitment success. Understanding the habitat characteristics that lead to reproductive success in White Sturgeon will be critical to prevent further decline of this important species.
USGS scientists from the Western Fisheries Research Center and Idaho Water Science Center teamed up to investigate why certain reaches of the Columbia River have consistent recruitment while other reaches have inconsistent or no recruitment. Data were collected in each reach related to substrate composition, embeddedness, and hydrodynamics, for use in the development of White Sturgeon habitat models. After model testing and verification, the scientists created a set of simulations to predict how White Sturgeon habitat may change under different physical conditions (i.e., flow, substrate composition, embeddedness). Model simulations revealed significant gains in White Sturgeon habitat in all three reaches when spring flows increased, embeddedness decreased, or gravel/cobble composition increased.
Information from this study was recently published in the journal Heliyon and should prove useful to biologists, water managers, and action agencies charged with maintaining or restoring White Sturgeon spawning habitat throughout the Columbia River Basin.
Hatten, J.R., M.J. Parsley, G.J. Garton, T.R. Batt, and R.L. Fosness. 2018. Substrate and flow characteristics associated with White Sturgeon recruitment in the Columbia River. Heliyon 4(5): e00629
Newsletter Author: Rachel Reagan
In The News
On January 31, 2019, Western Fisheries Research Center, Director Jill Rolland was interviewed by a reporter from the Norwegian-American weekly about fish farming in the U.S. and Norway. The article will be a general interest story about fish farming.
New publication examines migratory coupling between predator and prey: Animal migrations are undertaken by some of the world’s most endangered taxa. Predators often exploit migrant prey, but the movements taken by these consumers are rarely studied or understood. In a review article of Nature Ecology and Evolution, scientists from University of New Hampshire, University of British Columbia, Oregon State University, and USGS Western Fisheries Research Center examine movements where migrant prey induce large-scale movements of predators (migrant coupling) and the ecological consequences for the participating prey, predators, and community they traverse across the landscape. The paper also provides a framework for interactions caused by migratory coupling and the potential community-level impacts.
Furey, N.B., J.B. Armstrong, D. Beauchamp, and S.G. Hinch. 2018. Migratory coupling between predators and prey. Nature Ecology and Evolution 2: 1846-1853.
Interactive tool explores fish use of eelgrass in Puget Sound: The degree to which eelgrass on river deltas provides critical habitat for estuarine fishes, especially outmigrating juvenile salmon, is an important scientific and management issue in the Puget Sound. In a journal article published in Marine and Coastal Fisheries, USGS scientists report on spatiotemporal variation in abundance and body size of juvenile Chinook Salmon and three forage fish species in relation to eelgrass on a large river delta in Puget Sound and consider how diking and river channelization potentially influenced eelgrass use by these fish. Now, in collaboration with scientist Sachin Shah of the USGS Texas Water Science Center, a data visualization tool has been developed to allow users to interactively explore fish abundance and body size including selecting any desired combination of location and time period. The tool takes 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. Shah is part of a teamfocused on Geospatial Science and Cyber Innovation that intersects science and technology using interdisciplinary expertise.
New publication explores ecological responses to dam removal: Many large river systems in the developed world have at least one but usually multiple dams on them. During the dam construction boom of the mid-20th century, the ecological costs were seldom considered or given equal weight to the perceived benefits. Now, in addition to mitigating impacts of current and future dams, society is also dealing with some existing dams by removing them. Although dams are removed for multiple reasons (e.g., safety, costs, loss of function), a common objective is the recovery of ecosystem function, often centered on species of economic and cultural importance. But how do ecosystems recover after dam removal, how long does it take, and do they resemble what existed prior to dam emplacement? In a new publication in Bioscience, scientists from multiple USGS centers, along with U.S. Forest Service, NOAA Fisheries, University of Montana, Bowling Green State University, and American Rivers, examine the ecological response to dam removal. They create conceptual diagrams and models of how physical and biological controls are linked, illustrating how ecological drivers and responses vary depending on location.
Bellmore, J.R., G.R. Pess, J.J. Duda, J.E. O’Connor, A.E. East, M.M. Foley, A.C. Wilcox, J.J. Major, P.B. Shafroth, S.A. Morley, C.S. Magirl, C.W. Anderson, J.E. Evans, C.E. Torgersen, and L.S. Craig. 2019. Conceptualizing ecological responses to dam removal: if you remove it, what’s to come? BioScience 69(1): 26-39.
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