Metcalf J.L.,University of Colorado at Boulder |
Metcalf J.L.,University of Adelaide |
Love Stowell S.,University of Colorado at Boulder |
Kennedy C.M.,U.S. Fish and Wildlife Service |
And 7 more authors.
Molecular Ecology | Year: 2012
Many species are threatened with extinction and efforts are underway worldwide to restore imperilled species to their native ranges. Restoration requires knowledge of species' historical diversity and distribution. For some species, many populations were extirpated or individuals moved beyond their native range before native diversity and distribution were documented, resulting in a lack of accurate information for establishing restoration goals. Moreover, traditional taxonomic assessments often failed to accurately capture phylogenetic diversity. We illustrate a general approach for estimating regional native diversity and distribution for cutthroat trout in the Southern Rocky Mountains. We assembled a large archive of historical records documenting human-mediated change in the distribution of cutthroat trout (Oncorhynchus clarkii) and combined these data with phylogenetic analysis of 19th century samples from museums collected prior to trout stocking activities and contemporary DNA samples. Our study of the trout in the Southern Rocky Mountains uncovered six divergent lineages, two of which went extinct, probably in the early 20th century. A third lineage, previously declared extinct, was discovered surviving in a single stream outside of its native range. Comparison of the historical and modern distributions with stocking records revealed that the current distribution of trout largely reflects intensive stocking early in the late 19th and early 20th century from two phylogenetically and geographically distinct sources. Our documentation of recent extinctions, undescribed lineages, errors in taxonomy and dramatic range changes induced by human movement of fish underscores the importance of the historical record when developing and implementing conservation plans for threatened and endangered species. © 2012 Blackwell Publishing Ltd.
Koel T.M.,National Park Service |
Kerans B.L.,Montana State University |
Barras S.C.,U.S. Department of Agriculture |
Hanson K.C.,U.S. Department of Agriculture |
Wood J.S.,Pisces Molecular LLC
Transactions of the American Fisheries Society | Year: 2010
Myxobolus cerebralis, the cause of whirling disease in salmonids, has dispersed to waters in 25 states within the USA, often by an unknown vector. Its incidence in Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri within the highly protected environment of Yellowstone Lake, Yellowstone National Park, is a prime example. Given the local abundances of piscivorous birds, we sought to clarify their potential role in the dissemination of M. cerebralis. Six individuals from each of three bird species (American white pelican Pelecanus erythrorhynchos, double-crested cormorant Phalacrocorax auritus, and great blue heron Ardea herodias) were fed known-infected or uninfected rainbow trout O. mykiss. Fecal material produced during 10-d periods before and after feeding was collected to determine whether M. cerebralis could be detected and, if so, whether it remained viable after passage through the gastrointestinal tract of these birds. For all (100%) of the nine birds fed known-infected fish, fecal samples collected during days 1-4 after feeding tested positive for M. cerebralis by polymerase chain reaction. In addition, tubificid worms Tubifex tubifex that were fed fecal material from known-infected great blue herons produced triactinomyxons in laboratory cultures, confirming the persistent viability of the parasite. No triactinomyxons were produced from T. tubifex fed fecal material from known-infected American white pelicans or double-crested cormorants, indicating a potential loss of parasite viability in these species. Great blue herons have the ability to concentrate and release viable myxospores into shallow-water habitats that are highly suitable for T. tubifex, thereby supporting a positive feedback loop in which the proliferation of M. cerebralis is enhanced. The presence of avian piscivores as an important component of aquatic ecosystems should continue to be supported. However, given the distances traveled by great blue herons between rookeries and foraging areas in just days, any practices that unnaturally attract them may heighten the probability of M. cerebralis dispersal and proliferation within the Greater Yellowstone Ecosystem. © Copyright by the American Fisheries Society 2010.
Forzan M.J.,Canadian Cooperative Wildlife Health Center |
Vanderstichel R.,University of Prince Edward Island |
Hogan N.S.,University of Prince Edward Island |
Teather K.,University of Prince Edward Island |
Wood J.,Pisces Molecular LLC
Diseases of Aquatic Organisms | Year: 2010
Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has resulted in the decline or extinction of approximately 200 frog species worldwide. It has been reported throughout much of North America, but its presence on Prince Edward Island (PEI), on the eastern coast of Canada, was unknown. To determine the presence and prevalence of Bd on PEI, skin swabs were collected from 115 frogs from 18 separate sites across the province during the summer of 2009. The swabs were tested through single round end-point PCR for the presence of Bd DNA. Thirty-one frogs were positive, including 25/93 (27%) green frogs Lithobates (Rana) clamitans, 5/20 (25%) northern leopard frogs L. (R.) pipiens, and 1/2 (50%) wood frogs L. sylvaticus (formerly R. sylvatica); 12 of the 18 (67%) sites had at least 1 positive frog. The overall prevalence of Bd infection was estimated at 26.9% (7.2-46.7%, 95% CI). Prevalence amongst green frogs and leopard frogs was similar, but green frogs had a stronger PCR signal when compared to leopard frogs, regardless of age (p < 0.001) and body length (p = 0.476). Amongst green frogs, juveniles were more frequently positive than adults (p = 0.001). Green frogs may be the most reliable species to sample when looking for Bd in eastern North America. The 1 wood frog positive for Bd was found dead from chytridiomycosis; none of the other frogs that were positive for Bd by PCR showed any obvious signs of illness. Further monitoring will be required to determine what effect Bd infection has on amphibian population health on PEI. © Inter-Research 2010.
Barry Nehring R.,300 South Townsend Avenue |
Hancock B.,Colorado State University |
Catanese M.,Colorado State University |
Stinson M.E.T.,Colorado State University |
And 3 more authors.
Journal of Aquatic Animal Health | Year: 2013
Elucidating the dynamics of a parasitic infection requiring two hosts in a natural ecosystem can be a daunting task. Myxobolus cerebralis (Mc), the myxozoan parasite that causes whirling disease in some salmonids, was detected in the Colorado River upstream of Windy Gap Reservoir (WGR) in 1988. Subsequently, whirling disease was implicated in the decline of wild Rainbow Trout Oncorhynchus mykiss in the river when WGR was identified as a point source of Mc triactinomyxons (TAMs). Between 1997 and 2004, numerous investigations began to elucidate the etiology of Mc in WGR. During this period, Mc TAM production in WGR declined more than 90%. Explanations for the decline have included differences in stream discharge between years, changes in the thermal regime of the lake, severe drought, changes in the fish population structure in WGR, and reductions in the prevalence and severity of Mc infection in salmonids in the Colorado and Fraser rivers upstream of WGR. All of these have been discredited as explanations for the reduced TAM production. In 2005, a new study was conducted to replicate the studies completed in 1998. In this paper, the results of a new real-time polymerase chain reaction assay utilized to quantify the mitochondrial 16S rDNA specific to each of four lineages of Tubifex tubifex in pooled samples of 50 oligochaetes are presented. These results suggest that compared with 1998, the densities of aquatic oligochaetes and T. tubifex have increased, TAM production has been greatly reduced, and the decline is congruent with the dominance of lineages I, V, and VI of T. tubifex-three lineages that are refractory or highly resistant to Mc infection-in the oligochaete population. While it is possible that the resistant lineages function as biofilters that deactivate Mc myxospores, the reason for the decline in TAM production in WGR remains an enigma. © American Fisheries Society 2013.
Forzan M.J.,Canadian Wildlife Health Cooperative |
Forzan M.J.,University of Prince Edward Island |
Jones K.M.,University of Prince Edward Island |
Vanderstichel R.V.,University of Prince Edward Island |
And 7 more authors.
Journal of General Virology | Year: 2015
Amphibian populations suffer massive mortalities from infection with frog virus 3 (FV3, genus Ranavirus, family Iridoviridae), a pathogen also involved in mortalities of fish and reptiles. Experimental oral infection with FV3 in captive-raised adult wood frogs, Rana sylvatica (Lithobates sylvaticus), was performed as the first step in establishing a native North American animal model of ranaviral disease to study pathogenesis and host response. Oral dosing was successful; LD50 was 102.93 (2.42–3.44) p.f.u. for frogs averaging 35 mm in length. Onset of clinical signs occurred 6–14 days post-infection (p.i.) (median 11 days p.i.) and time to death was 10–14 days p.i. (median 12 days p.i.). Each tenfold increase in virus dose increased the odds of dying by 23-fold and accelerated onset of clinical signs and death by approximately 15%. Ranavirus DNA was demonstrated in skin and liver of all frogs that died or were euthanized because of severe clinical signs. Shedding of virus occurred in faeces (7–10 days p.i.; 3–4.5 days before death) and skin sheds (10 days p.i.; 0–1.5 days before death) of some frogs dead from infection. Most common lesions were dermal erosion and haemorrhages; haematopoietic necrosis in bone marrow, kidney, spleen and liver; and necrosis in renal glomeruli, tongue, gastrointestinal tract and urinary bladder mucosa. Presence of ranavirus in lesions was confirmed by immunohistochemistry. Intracytoplasmic inclusion bodies (probably viral) were present in the bone marrow and the epithelia of the oral cavity, gastrointestinal tract, renal tubules and urinary bladder. Our work describes a ranavirus–wood frog model and provides estimates that can be incorporated into ranavirus disease ecology models. © 2015 The Authors.
Forzan M.J.,University of Prince Edward Island |
Wood J.,Pisces Molecular LLC
Journal of Wildlife Diseases | Year: 2013
Rana virus (Iridoviridae) infection is a significant cause of mortality in amphibians. Detection of infected individuals, particularly carriers, is necessary to prevent and control outbreaks. Recently, the use of toe clips to detect rana virus infection through PCR was proposed as an alternative to the more frequently used lethal liver sampling in green frogs (Rana [Lithobates] clamitans). We attempted reevaluate the use of toe clips, evaluate the potential use of blood onto filter paper and hepatic fine needle aspirates (FNAS) as further alternatives, and explore the adequacy of using green frogs as a target-sampling species when searching for rana virus infection in the wild. Samples were obtained from 190 post metamorphic (≥1-yr-old) green frogs from five ponds on Prince Edward Island (PEI), Canada. Three of the ponds had contemporary or recent tadpole mortalities due to Frog Virus 3 (FV3) rana virus. PCR testing for rana virus DNA was performed on 190 toe clips, 188 blood samples, 72 hepatic FNAS, and 72 liver tissue samples. Only two frogs were rana virus-positive: liver and toe clip were positive in one, liver only was positive in the other; all blood and FNAS, including those from the two positive frogs, were negative. Results did not yield a definitive answer on the efficacy of testing each type of sample, but resemble what is found in salamanders infected with Ambystoma tigrinum (rana)virus. Findings indicate a low prevalence of FV3 in post metamorphic green frogs on PEI (≤2.78%) and suggest that green frogs are poor reservoirs (carriers) for the virus. © Wildlife Disease Association 2013.