Metolius River Research Articles

Rearing environment influences boldness and prey acquisition behavior, and brain and lens development of bull trout

Animals reared in barren captive environments exhibit different developmental trajectories and behaviors than wild counterparts. Hence, the captive phenotypes may influence the success of reintroduction and recovery programs for threatened and endangered species. We collected wild bull trout embryos from the Metolius River Basin, Oregon and reared them in differing environments to better understand how captivity affects the bull trout Salvelinus confluentus phenotype. We compared the boldness and prey acquisition behaviors and development of the brain and eye lens of bull trout reared in conventional barren and more structurally complex captive environments with that of wild fish. Wild fish and captive reared fish from complex habitats exhibited a greater level of boldness and prey acquisition ability, than fish reared in conventional captive environments. In addition, the eye lens of conventionally reared bull trout was larger than complex reared captive fish or same age wild fish. Interestingly, we detected wild fish had a smaller relative cerebellum than either captive reared treatment. Our results suggest that rearing fish in more complex captive environments can create a more wild-like phenotype than conventional rearing practices. A better understanding of the effects of captivity on the development and behavior of bull trout can inform rearing and reintroduction programs though prediction of the performance of released individuals.

Recruitment of Young Bull Trout into the Metolius River and Lake Billy Chinook, Oregon

AbstractThe abundance of Bull Trout Salvelinus confluentus in the Metolius River and Lake Billy Chinook, a hydroelectric reservoir, increased dramatically from 1998 to 2004, following implementation of restrictive fishery regulations. However, both adult Bull Trout and kokanee Oncorhynchus nerka (prey) populations have declined in more recent years. We investigated the relationships between Bull Trout spawner densities, emerging fry densities, and numbers of juveniles migrating into the reservoir to determine the potential role of juvenile production in this decline. We hypothesized that age‐1 and older juvenile production is now limited by natal habitat capacity and that excess fry production is lost to density‐dependent mortality. Bull trout redd densities in surveyed spawning reaches ranged from 14 to 39 redds/km during recent years. The estimated abundance of emerging Bull Trout fry in monitored spawning reaches has varied from about 1.0–2.5 million annually since 2005, while mean estimated densities of newly emerged fry varied from over 35/m2 in Roaring Creek during 2005 to less than 1/m2 in Jefferson Creek during 2009. Fry capture numbers from high versus low escapement broods at the Metolius River downstream trap varied by a factor of four, but capture of age‐1 and age‐2 juveniles did not differ substantially. These findings indicate natal Bull Trout habitats are seeded at spawner densities of 14 redds/km and higher. Fry in excess of natal habitat capacity are probably lost to density‐dependent mortality factors. We estimate natural recruitment of age‐1 and older Bull Trout into Lake Billy Chinook of at least 9 individuals/ha annually since 2001. Recent population bottlenecks limiting adult Bull Trout abundance occurred after juvenile recruits entered the lake and are probably related to prey availability.Received February 23, 2015; accepted July 8, 2015

Accounting for Tag Loss and Its Uncertainty in a Mark–Recapture Study with a Mixture of Single and Double Tags

AbstractUnless accounted for in the estimation, tag loss will cause mark–recapture methods to overestimate the true abundance of a closed population and to underestimate the associated uncertainty. Current methods of accounting for tag loss require all marked individuals to be double‐tagged. We present a new model that fully accounts for tag loss and allows for the use of a mixture of single‐ and double‐tagged individuals, thus simplifying implementation in the field. Treating abundance, tag loss rate, and capture probabilities as free parameters, we estimated those parameters and their uncertainty by using maximum likelihood. Whereas existing methods assume that a double‐tagged animal does not lose both tags, the new model allows the animal to lose both tags. The new model's performance was assessed and compared with that of other estimators (modified Petersen and Seber–Felton) via simulation. As expected, estimates from the new model were less biased and more precise than estimates from the other models. The model was used to estimate the abundance of the kokanee Oncorhynchus nerka population in the Metolius River, Oregon, during 2007. Abundance was estimated at 102,970 fish (), tag loss rate was estimated at 0.27 (), the capture probability for the first sample (tagging) was 0.03 (), and the capture probability for the second sample (recovery) was 0.11 (). The new model uses all of the information from single‐ and double‐tag data, provides unbiased abundance estimates in the presence of tag loss for a closed population, and has less‐stringent field requirements that make it easier to employ than other methods.

CLUTCH MORPHOLOGY AND THE TIMING OF EXPOSURE IMPACT THE SUSCEPTIBILITY OF AQUATIC INSECT EGGS TO ESFENVALERATE

We investigated Baetis spp. (mayfly), Hesperoperla pacifica (stonefly), and Brachycentrus americanus (caddisfly) susceptibility at the egg stage to esfenvalerate, a synthetic pyrethroid insecticide. Eggs were obtained from the field or from field-collected gravid females at sites near Corvallis (OR, USA) and the Metolius River at Camp Sherman (OR, USA) for static exposures under controlled conditions for temperature and light. Eggs were exposed to esfenvalerate for 48 h at concentrations ranging from 0.025 to 4.0 microg/L. No effect on mortality or posthatch growth was detected in H. pacifica eggs exposed to esfenvalerate concentrations up to 1.0 microg/L. Exposure to 0.07 microg/L of esfenvalerate, however, caused a significant increase in Baetis spp. egg mortality, and exposure of near-eclosion eggs to lower concentrations (0.025 and 0.05 microg/L) resulted in behavioral effects and reduced survivorship in newly hatched Baetis nymphs. Early stage B. americanus eggs were 10-fold more sensitive to esfenvalerate when removed from the gelatinous clutch before exposure, an indication that the gelatin affords protection from toxicant exposure. Exposures of near-hatch B. americanus clutches to esfenvalerate concentrations ranging between 0.035 and 0.2 microg/L, however, resulted in significant clutch death within clutches resulting from behavioral aberrations of first-instar larvae. The results of the present study suggest that aquatic insect egg clutch morphology can be a strong influence on susceptibility of embryos to esfenvalerate exposure.

Use of a simulation model and ecosystem flux data to examine carbon-water interactions in ponderosa pine.

Drought stress plays an important role in determining both the structure and function of forest ecosystems, because of the close association between the carbon (C) and hydrological cycles. We used a detailed model of the soil-plant-atmosphere continuum to investigate the links between carbon uptake and the hydrological cycle in a mature, open stand of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) at the Metolius river in eastern Oregon over a 2-year period (1996-1997). The model was parameterized from local measurements of vegetation structure, soil properties and meteorology, and tested against independent measurements of ecosystem latent energy (LE) and carbon fluxes and soil water content. Although the 2 years had very different precipitation regimes, annual uptake of C and total transpiration were similar in both years, according to both direct observation and simulations. There were important differences in ratios of evaporation to transpiration, and in the patterns of water abstraction from the soil profile, depending on the frequency of summer storms. Simulations showed that, during periods of maximum water limitation in late summer, plants maintained a remarkably constant evapotranspirative flux because of deep rooting, whereas changes in rates of C accumulation were determined by interactions between atmospheric vapor pressure deficit and stomatal conductance. Sensitivity analyses with the model suggest a highly conservative allocation strategy in the vegetation, focused belowground on accessing a soil volume large enough to buffer summer droughts, and optimized to account for interannual variability in precipitation. The model suggests that increased allocation to leaf area would greatly increase productivity, but with the associated risk of greater soil water depletion and drought stress in some years. By constructing sparse canopies and deep rooting systems, these stands balance reduced productivity in the short term with risk avoidance over the long term.

Molecular Epidemiology Reveals Emergence of a Virulent Infectious Hematopoietic Necrosis (IHN) Virus Strain in Wild Salmon and Its Transmission to Hatchery Fish

Infectious hematopoietic necrosis virus (IHNV) has been known to be a significant salmonid pathogen in the Pacific Northwest of North America for decades. The goal of this study was to characterize the IHNV genetic heterogeneity and viral traffic over time at a study site in the Deschutes River watershed in Oregon, with an emphasis on the epidemiology of IHNV types causing epidemics in wild kokanee Oncorhynchus nerka between 1991 and 1995. The study site included kokanee spawning grounds in the Metolius River and Lake Billy Chinook downstream, in which the IHNV epidemics occurred in 2- and 3-year-old kokanee, and the Round Butte Fish Hatchery at the outflow of the lake. Forty-two IHNV isolates collected from this area between 1975 and 1995 were characterized on a genetic basis by ribonuclease (RNase) protection fingerprint analyses of the virus nucleocapsid, glycoprotein, and nonvirion genes. Analysis of the 16 identified composite haplotypes suggested that both virus evolution and introduction of new IHNV strains contributed to the genetic diversity observed. The results indicated that the 1991–1995 epidemics in kokanee from Lake Billy Chinook were due to a newly introduced IHNV type that was first detected in spawning adult kokanee in 1988 and that this virus type was transmitted from the wild kokanee to hatchery fish downstream in 1991. Twelve IHNV haplotypes were found at Round Butte Fish Hatchery, indicating a series of virus displacement events during the 20-year period examined. This work shows that IHNV traffic can be much more complex than was previously recognized, and the results have implications for fisheries management at the hatchery and throughout the watershed.

Introgression and Susceptibility to Disease in a Wild Population of Rainbow Trout

We examined susceptibility of wild rainbow trout Oncorhynchus mykiss from the Metolius River, a tributary of the Deschutes River, Oregon, to genetic introgression and cerato myxosis as a result of stocking nonnative hatchery rainbow trout. Ceratomyxa shasta, an enzootic myxosporean parasite that can be lethal to nonnative hatchery rainbow trout, might have been limiting the interbreeding of hatchery and wild rainbow trout in the river. However, rainbow trout from the Metolius River had allozyme frequencies intermediate between those of wild and hatchery fish at LDH-82* and sSOD-1*, two diagnostic genetic loci that allow the inland subspecies of rainbow trout to be distinguished from hatchery strains of coastal origin. They also had notable frequencies of ADA-1 *85, an allele documented in hatchery rainbow trout but rarely seen in wild populations. We also found that rainbow trout in the Metolius River averaged 138.9 scales in the lateral series, intermediate between the counts for 9 coastal or nonnative hatchery populations, which always had fewer than 140 scales, and 10 inland populations, which always had more than 140 scales. Disease challenges revealed that rainbow trout from the Metolius River had much greater susceptibility to C. shasta than rainbow trout from the Deschutes River, which have genetic resistance to the lethal disease. Based on these data, we concluded that introgression with nonnative hatchery rainbow trout has reduced the abilities of wild rainbow trout in the Metolius River to survive when conditions for ceratomyxosis infection occur.

Localized Genetic Effects of a Long-Term Hatchery Stocking Program on Resident Rainbow Trout in the Metolius River, Oregon

Abstract Hatchery rainbow trout Oncorhynchus mykiss have been stocked in the Metolius River in central Oregon since 1938, and legal-sized (≥160 g) yearling trout were stocked annually from 1947 until 1995. In 1996, management objectives shifted to emphasize wild trout, and hatchery stocking ceased. We examined allozyme and mitochondrial DNA (mtDNA) variation among three naturally occurring populations of rainbow trout in the Metolius River to investigate possible hybridization with hatchery-produced rainbow trout. We also examined two commonly used hatchery strains of rainbow trout, one of which has supplied nearly all of the catchable hatchery trout in the Metolius. Both allozyme and mtDNA data showed the two hatchery samples to have genetic characteristics typical of hatchery populations derived from coastal rainbow trout O. mykiss irideus. Rainbow trout sampled from the lower Metolius River, approximately 30 km downstream of the headwaters, had allozyme and mtDNA characteristics typical of interior rai...

Molecular filtration for recovery of waterborne viruses of fish.

The effectiveness of tangential flow filtration (TFF) for the recovery of infectious hematopoietic necrosis virus (IHNV) and infectious pancreatic necrosis virus (IPNV) from large volumes of water was evaluated. In laboratory studies, virus recovery from IHNV-seeded water following concentration by TFF was approximately 13%. However, the addition of 0.1 and 1% fetal bovine serum to deionized water stabilized the virus, increasing virus recoveries to 95%. The addition of 0.03 and 0.3% beef extract resulted in IHNV recoveries of 80 and 61%, respectively. Similar results were obtained with IPNV-seeded water. Field studies using the TFF procedure were conducted with water from areas where IHNV is endemic. IHNV was detected in effluent from an adult steelhead trout (Salmo gairdneri) holding pond at an estimated concentration of 1 PFU/5 ml of water. It was also detected at levels of 1 PFU/50 ml in water from a 2-m-diameter circular tank containing IHNV-infected steelhead trout fry. IHNV isolated in samples taken from the Metolius River was detected by TFF at estimated levels of 1 PFU/3 liters.

Observations on North American Gomphoneis (Bacillariophyceae). II. Descriptions and Ultrastructure of Two New Species

Two new species of the diatom genus Gomphoneis are described from Oregon (U.S.A.). Light and scanning electron microscopic observations of C. trullata n. sp. show that this diatom has striae with two rows of indistinct, slit-like puncta and an axial plate located circa 1/2-2/ the way between the axial area and the valve margin. As in other species of Gomphoneis, the axial plate is responsible for the image of longitudinal lines characteristic of the genus. Gomphoneis trullata is distinguished from previously described species by its distinctively shaped valves, which are widest between the central area and the footpole, and by the position of the longitudinal lines. The second species, G. linearis n. sp., is a rare form known only from the Metolius River. It is distinguished by its linear valve outline, submarginal longitudinal lines, and distinct doubly-punctate striae. The diatom genus Gomphoneis Cleve (exclusive of forms recently transferred from Gomphonema C.A.Ag. by Carter & Bailey-Watts, 1981; Dawson, 1974; and Lange-Bertalot, 1978) is relatively small, with but 11 taxa represented in the United States flora (Lohman, 1964; Patrick, 1975; Reimer, 1982; Schmidt, 1899). The genus also is restricted in distribution, with most previously described taxa being from Lake Baikal, U.S.S.R. (Skvortzow & Meyer, 1928), the Pacific Northwest, U.S.A. (Ehrenberg, 1854; Grunow, 1880; Schmidt, 1899), and the Great Lakes (Ehrenberg, 1854; Grunow, 1878). Other distributional reports include New Zealand (Foged, 1979; Wood, 1961), Australia (Wood, 1961), Great Smoky Mountains (Kociolek, 1982), Iowa (Reimer, 1982; Stoermer, 1964), France (Brun & Heribaud, 1893) and Chile (Rivera & Valdebenito, 1979). Although investigators have questioned the validity of the genus (see Lange-Bertalot, 1980), recent studies on Gomphoneis mammilla (Ehrenb.) Cl. (Kociolek & Rosen, 1984) support the separation of Gomphoneis from the closely allied genus Gomphonema. Comphoneis differs from Gomphonema by having a combination of (usually) double rows of puncta in the striae and longitudinal lines on either side of the axial area. The image of longitudinal lines has been shown to be produced by the edges of an expanded internal axial plate that underlies a portion of the striae (Kociolek & Rosen, 1984). 1 Contribution no. 439 of the Great Lakes Research Division. 2 We are indebted to Dr. Ed Theriot, Great Lakes Research Division, for help with the Latin diagnoses. Dr. Charles W. Reimer, Academy of Natural Sciences of Philadelphia, critically read the manuscript. Dr. C. David Mclntire, Department of Botany and Plant Pathology, Oregon State University, kindly provided laboratory facilities to J.P.K. This work was supported by NSF Grant BSR-8500263. TRANS. AM. MICROSC. Soc., 105(2): 141-151. 1986. ? Copyright, 1986, by the American Microscopical Society, Inc. This content downloaded from 207.46.13.111 on Tue, 09 Aug 2016 05:01:56 UTC All use subject to http://about.jstor.org/terms TRANS. AM. MICROSC. SOC. Recent collections from fresh-water habitats in Oregon (U.S.A.) have yielded two species of Comphoneis, which are described below. MATERIALS AND METHODS Material was collected by the senior author from the Metolius River and neighboring unnamed tributaries in the Camp Sherman Area, Jefferson County, Oregon, and Linton Lake and its environs in the McKenzie Pass Area, Lane County, Oregon (U.S.A.). Collections were cleaned in nitric acid and processed according to procedures described by Patrick & Reimer (1966), or cleaned and processed according to the method of van der Werff (1955). Cleaned material was air-dried onto coverslips and mounted in Hyrax or Cumarone R-9 (Holmes et al., 1981) and observed with a Leitz Dialux-20 or Ortholux light microscope outfitted with bright-field optics. For scanning electron microscopy (SEM), cleaned material was air-dried onto coverslips, which then were mounted onto aluminum stubs. Stubs bearing the cleaned material were sputter-coated with approximately 15 nm of goldpalladium and viewed with an ISI DS-130 scanning electron microscope, operated at 10-15 kV.

Quaternary glaciation and volcanism, Metolius River area, Oregon

Evidence of three major Quaternary glaciations is recognized in the Metolius River area on the east flank of. the High Cascades. The latest glaciation (Cabot Creek glaciation) is multiple, with evidence of a late readvance (Canyon Creek advance) well displayed in cirques. Post-Altithermal glacial activity is restricted to a twofold late Neoglacial advance on Mount Jefferson and Three-Fingered Jack. Stone-weathering characteristics and soil development are used to differentiate and correlate the drifts throughout the area. The degree of soil development on the drifts suggests that there was a longer period of time between the oldest and intermediate glaciations than between the intermediate and youngest glaciations. Volcanic activity may have been restricted to times of little ice cover, since no evidence of intraglacial volcanism was observed. Tephra and lava flows were erupted during two Pleistocene interglaciations and during Holocene time at scattered locations. The High Cascade platform and probably the stratovolcanoes were largely constructed prior to the earliest recognized glaciation (Abbott Butte glaciation). Information on extent of ice cover during the Cabot Creek glaciation and the Neoglacial advance is sufficiently detailed to reconstruct past glacier margins and estimate former equilibrium-line altitudes (ELA). An accumulation-area ratio of 0.6 ± 0.1 was employed to calculate past ELAs. During the Cabot Creek glaciation, ELAs ranged from about 950 m lower than present at the maximum to 700 to 750 m lower than present for the Canyon Creek advance. Neoglacial ELAs on Mount Jefferson glaciers were lower than present by 200 to 250 m. ELA gradients across the Western Cascades during the Cabot Creek glaciation averaged about 5 m/km, increased to 14 m/km across the High Cascades, and were greater than 38 m/km farther east. This reflects a pattern of precipitation similar to that of the present.

BENTHIC ALGAL COMMUNITIES OF THE METOLIUS RIVER1,2

SUMMARYSampling of benthic algae from selected sites in the Metolius River was carried out at regular intervals between April 15, 1967 and March 9, 1968 to determine the species composition of the communities. With the exception of the sampling site at the headwaters and the site immediately downstream, the benthic community of the Metolius River is described as a Cladophora–Achnanthes–Spirogyra community, with species of these 3 genera predominating on a year‐round basis. The community described for the headwaters and the sampling site immediately downstream was composed primarily of Nitzchia palea and Cymbella cistula. Of the approximately 60 species of algae which were identified, only 9 showed a definite seasonal distribution, the remaining species being found on a year‐round basis.

Metoliophilus uvaticus gen. et sp. n. (Lecithodendriidae: Metoliophilinae subf. n.) from the Dipper, Cinclus mexicanus, in Oregon

Metoliophilus uvaticus is described as a new genus and species of intestinal trematode, collected from adult and nestling dippers in Oregon. It is characterized by a covering of integumental scales; ceca of moderate length; cirrus sac mainly anterior and to the left of acetabulum, directed posteriad; genital pores separate but adjacent, submedian, near posterior margin of acetabulum; ovary deeply lobed, between intestinal fork and testes; and tubular excretory vesicle. A new subfamily is erected for this genus. Egg-producing adults were obtained in chicks 5 days after feeding metacercarial cysts from nymphs of the stonefly, Acroneuria pacifica (Banks). After 10 days adult flukes were found in the muscular layer of the bird's intestinal wall. Most nymphs of the large stonefly, Acroneuria pacifica (Banks), collected in the Metolius River near Camp Sherman, Deschutes County, on the eastern slope of the Cascade Mountains in central Oregon, were found to contain encysted metacercariae. When fed to day-old chicks of Gallus gallus domesticus, these developed in the small intestine into mature trematodes identified as a new species, genus, and subfamily of the Lecithodendriidae. One specimen of this fluke with few eggs was found in a dipper from the same locality; a second specimen without eggs was taken from a dipper collected from Nehalem, near the Oregon coast; and 14 large individuals with numerous eggs were found in one of four nestling dippers collected near the Nehalem River, Clatsop County, about 20 miles upstream from Nehalem. Dippers from streams along the Columbia River Gorge, Multnomah County, were negative for this fluke.

BIOLOGY AND DOWNSTREAM DRIFT OF SOME OREGON TRICHOPTERA

AbstractData are given on the biology of several species of Trichoptera in the Metolius River, Oregon, based on drift and benthos samples. Twenty-seven species were collected. Species of Limnephilidae, Brachycentridae, Hydroptilidae, and Lepidostomatidae were important drift components. The Metolius River is extremely productive, with a mean density of larval Trichoptera of 7400 per square meter in benthos samples and a maximum of 5000 per 24 hours in drift-trap samples. Different species varied in their tendency to drift, in the age class distribution in the drift, and in diel periodicity. Drift-trap collecting is shown to be a useful method of studying aspects of behavior such as the dispersal of larvae and the emergence of pupae.

Discussion of “Runoff from rain and snow” by Arthur M. Piper

As a basis to study the discharge characteristics of the Metolius River the John Day River was used. The Deschutes Basin of which the Metolius drainage area is a part was compared to the John Day Basin. There are several factors which must be considered when comparing the two basins. Perhaps the most important point which was not stresses is the fact that although about three‐fourths of the flow of the Deschutes River rises in the western most part of the Deschutes Basin, which part was more or less exempted by Piper in his discussion of general runoff characteristics, it is less than half of the Deschutes Watershed.

Runoff from rain and snow

The basic principles of the idealized hydrologic cycle are reviewed with emphasis on storage and movement of water in the soil. A distinction is made between ground‐water runoff and overland runoff in terms of storage and lag, expressed as accumulated deviations from uniform flow over a period of several years. These functions are presented for the period 1920 through 1945 for three rivers in central Oregon: John Day, Deschutes, and Metolius, which exemplify minimum, moderate, and maximum effects, respectively, of storage and lag. The Metolius River is shown to have extremely small fluctuations in discharge from year to year, ascribed to a great portion of its flow being derived from ground‐water runoff; and its response to fluctuations in annual precipitation lags behind that of the John Day River by about five years. Specific techniques and measures for improving seasonal water supply forecasts are suggested.