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Western Fisheries Science News, July 2016 | Issue 4.7

Developing Water Temperature Models to Help Understand Fish Population Dynamics and Management Actions

Photograph showing sunrise on the Trinity River, northern California. Photo by Edward C. Jones, USGS.

Water temperature is known to be a critical factor influencing fish populations, as well as the structure of the food webs on which they depend. Salmon population dynamics are affected by water temperature in many crucial ways such as egg incubation rates, individual growth rates, migration timing, and disease susceptibility. Given its importance, having a temperature model for a basin can be useful for understanding the effects of water management actions and fish population dynamics. For example, in the Klamath Basin, fisheries and water managers are interested in understanding the effects of management actions on water temperature, and consequent effects on Pacific salmon downstream of dams.

In a recent USGS report authored by USGS (WFRC and OR Water Science Center) and U.S. Fish and Wildlife Service (USFWS), scientists present a water temperature model (River Basin Model-10; RBM10) for the Trinity River, a major tributary to the Klamath River.  The research was supported by USFWS and Bureau of Reclamation and involved contributions from many agencies and tribes in the region. The model uses publicly available simulated meteorological data and observed streamflow data to estimate daily mean water temperature. The authors constructed the water-temperature model to simulate Trinity River temperatures along the 112 miles from Lewiston Dam to the Klamath River confluence, 1980–2013. The model was calibrated to eight locations where observed water temperatures were available, and can output temperature and flow at any user specified location.

Scientists used RBM10 to simulate water temperatures under three flow augmentation scenarios to demonstrate how the model can be used to assess potential water-management decisions. The goal was to evaluate how cold water released at Lewiston Dam would influence water temperatures in the lower Klamath River during a severe drought, by comparing the results to the historical baseline. For this evaluation, temperatures near or exceeding 23 °C are of particular interest, because this has been identified as a threshold that impairs the upstream migration of adult salmon—a threshold regarded as a “thermal migration barrier.” Outputs from the Trinity River water-temperature model were then used as inputs to an existing water-temperature model of the Klamath River to assess the effect of augmentation flow releases on water temperatures in the lower Klamath River. Results showed that management alternatives led to different water temperatures, in some cases mitigating higher temperatures that can inhibit upstream migration of salmon and promote epizootic outbreaks.

The Trinity River water-temperature model will be used to further our understanding of the relationship between water temperature and salmon populations of the Klamath Basin, and to improve the ability of managers to make informed water-management decisions.  This tool will be especially valuable during periods of drought, which are forecast to increase in frequency with climate change.

The next step in this research is to release a combined Klamath-Trinity RBM10 water-temperature model that can be used to directly inform real-time resource management decisions. To this end, scientists have developed a Graphical User Interface (GUI) for an integrated Klamath-Trinity version of the RBM10 water temperature model (available later this year, contact Ted Jones or Russell Perry if you are interested). Salmon life-cycle modeling efforts currently underway are already utilizing the temperature model, which will further bolster the decision-support tools available for managers in the Klamath Basin.

Newsletter Author - Rachel Reagan



USGS Scientist Travels to China as Part of a World Organization for Animal Health International Project: On June 26-30th, 2016, WFRC Scientist, Jim Winton, visited the Key State Laboratory of Aquatic Animal Diseases in Shenzhen, China to participate in a wrap-up meeting for an international project funded by the World Organization for Animal Health (OIE). The goal of the project is to increase the number of OIE Reference Laboratories in the world, especially in countries with significant problems from diseases listed by the OIE. The WFRC is currently the sole OIE Reference Laboratory for infectious hematopoietic necrosis (IHN), a virus disease of salmonid fish that was originally endemic to North America, but has emerged to become a significant problem affecting coldwater aquaculture in Asia. The goal of the project is to provide the training and experience to allow the Key State Laboratory of Aquatic Animal Diseases to be designated as a new OIE Reference Laboratory for IHN.

USGS Scientist Presents Findings at International Fish Health Conference: WFRC scientist, John Hansen, recently presented three studies at the 2nd International Conference on Fish and Shellfish Immunology in Portland, ME, from June 27 - June 30, 2016. The presentations dealt with 1) the impact of endocrine disruptors on innate immunity in zebrafish, 2) the role of temperature for the invasion, attachment and growth of Francisella noatunensis (an emerging fish pathogen) in tilapia cells lines and 3) the formation of a collaborative immune reagent network (CIRNAS) for salmon, catfish and tilapia. The research involves collaborations between the WFRC and the USGS Columbia Environmental Research Center, the University of New Mexico, University of Pennsylvania and the University of California at Davis.

In the News

On June 28, 2016, WFRC scientist Paul Hershberger and the WFRC’s Marrowstone Marine Field Station was featured on Seattle television station KING-5 about research that is investigating the impacts of a small parasite, nanophyetus, on steelhead around Puget Sound. Researchers are looking for the cause of die-offs and diminishing returns of steelhead around Puget Sound.

In recent news from the American Fisheries Society, research by USGS scientists and colleagues from the University of Illinois was featured about asian carp. The article describes how adding carbon dioxide gas to water could help control the movement and behavior of invasive carp in the Great Lakes basin.

On July 16, 2016, research by WFRC scientist Jim Hatten and co-authors was featured in the Summit County Citizens Voice about how climate change may affect birds and reptiles in the Southwest.


Friend, S.E., J. Lovy, and P.K. Hershberger. 2016. Disease surveillance of Atlantic herring: molecular characterization of hepatic coccidiosis and a morphological report of a novel intestinal coccidian. Dis. Aquat. Org. 120: 91-107.

Perry, R.W., T.J. Kock,, I.I.Courter, T.M Garrison, J.D., Hubble, and D.B. Child. 2016. Dam operations affect route-specific passage and survival of juvenile Chinook salmon at a main-stem diversion dam. River Res. Appl. 32(10): 2009-2019.

Perry, R.W., R.A. Buchanan, P.L. Brandes, J.R. Barau, and J.A. Israel. 2016. Anadromous salmonids in the Delta: New science 2006-2016. Special Issue: The State of Bay-Delta Science 2016, Part 1 in San Francisco Estuary and Watershed Science, 14(2), Article 7