Introduction Myxobolus cerebralis , the parasite responsible for salmonid whirling disease, was unintentionally introduced to and became established in Colorado 1990s. Mortality of young-of-year fish due infection by M. resulted recruitment failure subsequent significant declines Rainbow Trout ( Oncorhynchus mykiss ) populations. The complex multistage lifecycle makes it difficult eradicate manage, hatchery control strategies do not work wild. A viable method that has been utilized wild...

Renibacterium salmoninarum, the cause of bacterial kidney disease (BKD), severely impacts salmonid populations. Much our understanding BKD pathology in salmonids comes from evaluating fatal infections wild populations or spawning Pacific Northwest salmonids. Our study investigated histological progression and load dynamics R. salmoninarum infection Chinook salmon following intraperitoneal injection to enhance disease's dynamics. Seventy presmolt were injected with ATCC-33209 isolate...

Effective disease surveillance relies on accurate pathogen testing and robust prevalence estimates. Diagnostic specificity (DSp), the probability that an uninfected animal tests negative, is high when false positives are low. sensitivity (DSe) infected positive; higher DSe means fewer negatives. However, negatives harder to estimate without a “gold standard”, assay can detect between 90 − 100% of true positive infections. Occupancy estimation infection offers one solution by allowing for...

Altering food web structure has been shown to influence mercury (Hg) concentrations in sport fish. Here, we describe a whole-system manipulation designed assess the effectiveness of stocking relatively high-quality, low-Hg prey (rainbow trout, Oncorhynchus mykiss ) as means increasing northern pike ( Esox lucius growth reduce Hg concentrations. A replicated pond experiment served reference for lake and provided information parameterize bioenergetics simulations. Results indicate that is...

We used a quantitative genetics approach and estimated broad sense heritability (h2b) of myxospore count the number genes involved in formation to gain better understanding how resistance Myxobolus cerebralis, parasite responsible for whirling disease, is inherited rainbow trout Oncorhynchus mykiss. An M. cerebralis-resistant strain trout, German Rainbow (GR), wild, susceptible Colorado River (CRR), were spawned create 3 intermediate crossed populations (an F1 cross, F2 intercross, B2...

Abstract The development of rainbow trout Oncorhynchus mykiss strains that are resistant to whirling disease has shown promise as a management tool for populations in areas where Myxobolus cerebralis is present. However, the physiological effects on characteristics necessary fish survival natural river conditions have not been tested many these strains. Five were evaluated their swimming ability and growth relation M. exposure: German (GR) strain (Hofer strain), susceptible Colorado River...

Abstract Portable radio frequency identification (RFID) PIT tag antenna systems are increasingly being used in studies examining aquatic animal movement, survival, and habitat use, their design flexibility permits application a wide variety of settings. We describe the construction, performance two portable floating RFID designed to detect fish that were unavailable for recapture using stationary antennas or electrofishing. A raft system was locate PIT‐tagged relatively long (i.e., ≥10 km)...

Myxobolus cerebralis caused severe declines in rainbow trout populations across Colorado following its introduction the 1980s. One promising approach for recovery of Colorado's has been production that are genetically resistant to parasite. We introduced one these crosses, known as GR×CRR (cross between German Rainbow [GR] and River [CRR] strains), upper River. The abundance, survival, growth stocked population was examined determine if GR×CRRs had contributed offspring age-0 population,...

Abstract Little is known about the effectiveness of fishways for restoring passage to inland (nonanadromous) salmonids. We used PIT telemetry evaluate biological a vertical‐slot fishway constructed restore adult Colorado River Cutthroat Trout Oncorhynchus clarkii pleuriticus (CRCT) in small Rocky Mountain stream. Our objectives were assess (1) efficacy (whether or not restored fish passage), (2) approach efficiency (the probability that tagged encountered fishway; an index population use),...

Abstract Walleyes Sander vitreus support important recreational and commercial fisheries, have been introduced into many systems throughout the United States Canada. Use of sterile triploid fish is a valuable management strategy for protecting native species from naturally reproducing populations predators like Walleyes. Hydrostatic pressure one more effective methods inducing triploidy in Walleyes, technique currently evolving. A 2.7-L capacity electric chamber (TRC-APV Aqua Pressure...

Abstract Stream habitat fragmentation caused by manmade structures is ubiquitous in Colorado, creating a need for passage solutions that accommodate multiple fish species. This study tested the effectiveness of rock‐ramp fishway passing nine species with range swimming abilities. The target design included Brassy Minnow Hybognathus hankinsoni (weakest swimming), Longnose Dace Rhinichthys cataractae , Sucker Catostomus catostomus and Brown Trout Salmo trutta (strongest swimming). Testing 46‐h...

Abstract Following establishment of Myxobolus cerebralis (the parasite responsible for salmonid whirling disease) in Colorado, populations Rainbow Trout Oncorhynchus mykiss experienced significant declines, whereas Brown Salmo trutta densities increased many locations across the state, potentially influencing success M. ‐resistant reintroductions. We examined effects removal on short‐term (3‐month) survival and movement two crosses reintroduced, Cache la Poudre River, Colorado. Radio...

Abstract The use of mobile radio frequency identification (RFID) systems to detect PIT tags has increased in support research on fish movement, population dynamics, and habitat use. We describe the development application a RFID system that incorporates GPS PIT‐tagged evaluate utilization streams. study was conducted two distinct phases. First, testing RFID–GPS were using georeferenced, rocks detection probability accuracy. Second, field deployed estimate abundance utilization. Detection...

Abstract Introduced pathogens can affect fish populations, and three main factors disease occurrence: the environment, host, pathogen. Manipulating at least one of these is necessary for controlling disease. Myxobolus cerebralis, parasite responsible salmonid whirling disease, became established in Colorado during 1990s caused significant declines wild Rainbow Trout Oncorhynchus mykiss populations. Attempts to re-establish have focused on manipulating host resistance. A strain known as GR ×...

Bacterial Kidney Disease, caused by Renibacterium salmoninarum (Rs), is widespread and can cause significant mortality at most life stages in infected salmonids. Rs commonly found inland trout, which be carriers of the bacterium. Lethal spawns used to control vertical transmission progeny through culling eggs from parents, but costly, time-consuming, negatively impact important rare brood stocks. Erymicin 200 an Investigational New Animal Drug (INAD) intended reduce levels hatchery stocks...

Aquatic pathogens are a major concern for fish hatchery production, fisheries management, and conservation, disease control needs to be addressed. Two important salmonid Myxobolus cerebralis Flavobacterium psychrophilum that cause whirling bacterial coldwater (BCWD), respectively. Innate resistance is potential option reducing disease-related mortality in hatchery-reared rainbow trout (Oncorhynchus mykiss, Walbaum). experiments were conducted assess pathogen of first-generation (F1) created...

Vertical transmission of Renibacterium salmoninarum has been well-documented in anadromous salmonids but not hatchery-reared inland trout. We assessed whether the bacterium is vertically transmitted cutthroat trout (Oncorhynchus clarkii) from a Colorado, USA hatchery, and rate male female brood fish. Adult fish were killed, tested for R. kidney, liver, spleen, ovarian fluid, blood mucus samples, then stripped gametes to create 32 families with four infection treatments (MNFN, MNFP, MPFN,...

Abstract Lepak JM, Fetherman ER, Pate WM, Craft CD, Gardunio EI. 2012. An experimental approach to determine esocid prey preference in replicated pond systems. Lake Reserv Manage. 28: 224–231. Competitive interactions between salmonids and white suckers (Catostomus commersonii) often result poor salmonid growth, condition, ultimately angler catch-per-unit-effort. Fisheries managers frequently introduce hybrid northern pike (Esox lucius) muskellunge (E. masquinongy), known as tiger...

Abstract The New Zealand mudsnail Potamopyrgus antipodarum is an invasive species that can be transported to and established in new bodies of water on gear used by aquatic professionals, anglers, recreationists. Sparquat 256, a standard disinfectant for controlling the spread mudsnails, was recently discontinued manufacturer. Our objective find industrial‐strength, commercially available quaternary ammonium compound (QAC) could replace 256 disinfection purposes. efficacy three products—Quat...

Efforts to advance fish health diagnostics have been highlighted in many studies improve the detection of pathogens aquaculture facilities and wild populations. Typically, a pathogen has required sacrificing fish; however, hatcheries valuable sometimes irreplaceable broodstocks, lethal sampling is undesirable. Therefore, development non-lethal methods high priority. The goal our study was compare with standardized kidney tissue that used detect Renibacterium salmoninarum infections...

Significant resources go toward rearing and stocking fish globally, yet poststocking survival is often low, largely due to high predation rates on hatchery-reared fish. Antipredator behavior has been enhanced in many species through exposure chemical cues that simulate events, but the implementation of such protocols may be logistically challenging. It suggested a single hatchery while en route locations sufficient enhance antipredator improve survival. We tested whether one-time conspecific...

Abstract A low concentration of dissolved oxygen (DO) is commonly the limiting factor in fish culture systems. Hypoxia tolerance Rainbow Trout Oncorhynchus mykiss can be affected by both history domestication and growth rate. As such, selecting strains for specific characteristics such as rate or disease resistance could potentially affect DO tolerance, making difficult. Here we used two experiments to examine differences lower concentrations among four crosses selected whirling Myxobolus...

Infectious bacterial pathogens are a concern for aquaculture as estimates suggest that billions of US dollars lost annually in due to disease. One the most prevalent salmonid is bacterium Flavobacterium psychrophilum causes coldwater We reviewed published F. literature and conducted Bayesian analysis examine large-scale patterns rainbow trout (Oncorhynchus mykiss) mortality associated with laboratory challenge. incorporated factors were common across majority exposure studies these included...