Publications

Increasing usage of non-medicinal methods (NMMs) to control sea louse infestations on salmon farms has raised questions about whether sea lice may be able to evolve tolerance of NMMs. Of particular concern is the potential for sea lice to evolve freshwater tolerance as a result of freshwater treatments. Wild trout and some juvenile salmonids swim into freshwater to control infestations...

The impacts of Ceratonova shasta on Klamath River salmonids have been the focus of tremendous research and monitoring over the past decade. Knowledge gained from the various studies has resulted in a growing suite of decision support tools that can be used to predict the prevalence of infection and mortality that can be expected from varying exposure concentrations to C. shasta...

Viral hemorrhagic septicemia virus (VHSV), a fish rhabdovirus, infects several marine and freshwater fish species. There are many strains of VHSV that affect different fish, but some strains of one genetic subgroup have gained high virulence in rainbow trout (Oncorhynchus mykiss). To define the genetic basis of high virulence in trout, we used reverse genetics to create chimeric VHSVs in...

A field study was conducted to estimate survival of juvenile Chinook salmon (Oncorhynchus tshawytscha) in Lookout Point Reservoir, Oregon, during 2018. The study consisted of releasing three groups of genetically-marked fish into the reservoir, and sampling them monthly. Juveniles were released during April 10–13 (116,708 fish), May 15–18 (31,911 fish), and June 19–20 (11,758 fish)...

Executive Summary Intermittent streams are important and productive for salmonid habitat. Rock Creek, in southeastern Washington, flows south to the Columbia River at river kilometer (rkm) 368 and is an intermittent stream of great significance to the Yakama Nation and to the Kah-miltpah (Rock Creek) Band in particular. Historically, native steelhead (anadromous form of rainbow trout...

Data from a 4-year capture and transport program were used to assess translocation as a management strategy for two long-lived, federally endangered catostomids in the Upper Klamath Basin, Oregon. Lost River (Deltistes luxatus) and shortnose (Chasmistes brevirostris) suckers, two species endemic to the Klamath Basin, were translocated from Lake Ewauna to Upper Klamath Lake in each of 4...

The 2011–2014 removal of two dams from the Elwha River, WA, delivered ~ 19 Mt of sediment to the marine environment, creating an opportunity to study the sensitivity of a coastal ecosystem to large-scale sediment input. Macroalgae, the primary habitat-forming species in the nearshore, disappeared from the region. It was hypothesized that this mortality event was caused by a reduction in...

The streaked horned lark (hereafter “lark”; Eremophila alpestris strigata) is a federally listed bird subspecies of the Pacific Northwest that occupies open landscapes with short vegetation and abundant bare ground. Across its breeding range, which has contracted dramatically, the lark relies primarily on human-modified habitats maintained in early successional states (e.g., agricultural...

Executive Summary Historically, populations of Lost River suckers (Deltistes luxatus) of the Upper Klamath Basin were so numerous that they were commercially harvested; however, declining numbers throughout the 20th century led to the listing of the species under the United States Endangered Species Act in 1988. Habitat destruction, poor water quality, competition with (and predation by)...

Executive Summary The Pahranagat roundtail chub (Gila robusta jordani; hereinafter “chub”) was federally listed as endangered in 1970 (U.S. Fish and Wildlife Service, 1970). In the decades following the listing, the chub has declined to extremely low numbers (Tuttle and others, 1990; Guadalupe, 2014). Loss of available habitat appears to be one of the main reasons for the decline of this...

Surveys of environmental DNA (eDNA) have become an important and multifaceted tool for monitoring and identifying distributions and occupancy of aquatic species. This tool is attractive because it is powerful, easy to apply, and provides an alternative to traditional field survey methods. However, validating eDNA survey methods against traditional field survey methods is warranted prior...

A trap-and-haul program is operated to move anadromous Pacific salmon (Oncorhynchus spp.) around dams and reservoirs in the Cowlitz River basin, Washington. The primary release site for adult fish is in Lake Scanewa, a small reservoir created by Cowlitz Falls Dam, the uppermost dam in the basin. Releases in the reservoir are terminated when reservoir water temperature is 16 degrees...