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Bonners Ferry, ID, United States

Neufeld M.D.,British Columbia Ministry of forests | Davis C.A.,British Columbia Ministry of forests | Cain K.D.,University of Idaho | Jensen N.R.,Cramer Fish science | And 2 more authors.
Journal of Applied Ichthyology

Summary: In the Kootenay River, British Columbia, Canada, burbot (Lota lota maculosa) numbers have diminished to near extirpation due to factors including physical changes to habitat and overfishing. Habitat restoration is currently underway but short-term recovery measures include the release of hatchery-reared burbot. Moyie Lake has been identified as a suitable brood source for a conservation aquaculture program but uncertainties remain regarding current population size, the feasibility of capturing broodstock and the ability to collect eggs from wild spawners. Specific objectives of our study were to: (i) develop a length at age key to provide a non-destructive means of population age structure identification, (ii) determine the location and general habitat characteristics of burbot spawning locations on Moyie Lake, (iii) provide a marked sample for future population estimation, and (iv) investigate the feasibility of collecting gametes for use in a conservation aquaculture program. A total of 181, 554, and 370 burbot were captured in 2009, 2010 and 2011, respectively. No significant relationship was established between length and age for burbot on Moyie Lake. Spawning burbot were observed over a number of different habitats, but high use areas consisted of steep banks dominated by a mix of gravel/boulder/cobble substrates. Mature burbot were reliably collected each year, and eggs from females were fertilized and transported to the hatchery. Egg survival was highly variable (range 0-98%) and resulted in an estimated 353429, 3032143, and 3970283 eggs for use in the aquaculture program in 2009, 2010 and 2011, respectively. Results of this study demonstrate that gametes can be collected from adult burbot during spawning and eggs can be successfully fertilized in the field. Further methodological refinement aimed at improving egg fertilization and subsequent survival to the hatchery will be important as recovery moves forward. © 2011 Blackwell Verlag, Berlin. Source

Minshall G.W.,Idaho State University | Shafii B.,University of Idaho | Price W.J.,University of Idaho | Holderman C.,Kootenai Tribe of Idaho | And 3 more authors.
Freshwater Science

Large impoundments remove substantial amounts of sediment and nutrients from rivers and often limit production by downstream primary producers and secondary consumers. Nutrient levels and macroinvertebrate and fish abundance in the lower Kootenai River (7th order, mean annual discharge = 454 m3/s) in Idaho and Montana declined dramatically after Libby Dam was built in 1972. A subsequent study implicated ultraoligotrophic conditions (total dissolved P [TDP] ≤ 2 μg/L TDP) as a principal causative agent and prompted an on-going experimental nutrient-addition program for the Kootenai River downstream from Libby Dam, with dosing at the Idaho-Montana border. Pre-treatment monitoring began in 2003 and liquid ammonium polyphosphate fertilizer (10-34-0) was added each year during the growing season from 2006 through 2010 with a target TDP concentration of 3 μg/L and TN:TP near 20:1. We studied benthic macroinvertebrate responses to the experimental addition and hypothesized moderate increases in invertebrate richness, abundance, and biomass with little change in assemblage structure. We used a before-after control-impact BACI design with macroinvertebrate samples collected pre-and post-treatment from July to early November 2003-2010 from fertilized and unfertilized reaches. After treatment, mean modified (Oligochaeta and Chironomidae subtaxa excluded) total abundance increased 72%, mean total abundance increased 69%, and mean biomass increased 48%. Abundance of Ephemeroptera, the principal insect order in the study area increased 66%. Filter-feeder abundance also increased, indicating increased suspended organic matter in addition to the attached forms consumed by other benthic macroinvertebrates. The first 5 y of experimental treatment resulted in increased food resources for resident native fishes with no major alteration of macroinvertebrate community structure or trophic pathways. © 2014 by The Society for Freshwater Science. Source

Benjankar R.,University of Idaho | Yager E.,University of Idaho | Tonina D.,University of Idaho | Merz N.,Kootenai Tribe of Idaho

We developed a geographic information systems (GIS)-based multi-metric assessment tool using model-simulated long-term vegetation data to assess changes in riparian ecosystems due to altered hydrologic regimes. This allowed us to estimate spatial changes in a riparian system over several decades at annual resolution, to study system trends through time, and the effect of multiple and time-distributed human activities. We applied the tool to assess human and hydrologic impacts, for two scenarios, pre-dam versus post-dam periods and pre-levee versus post-levee periods on the Kootenai River. The pre-dam versus post-dam scenario considers two distinct hydrologic regimes as a result of dam operation, whereas the pre-levee versus post-levee scenario has one single natural hydrologic regime. We compared riparian ecosystem, community composition and native woody riparian vegetation index scores within the two scenarios. Our results showed that all three time-averaged index scores (riparian ecosystem, community composition and native woody vegetation) were statistically higher for the pre-dam than the post-dam period. In contrast, differences in index scores were small and were not statistically significant between pre-levee and post-levee periods. Thus, our GIS-based assessment tool can detect the impact of human-induced changes in the natural hydrologic regime on riparian ecosystems both temporally and spatially. © 2016 John Wiley & Sons, Ltd. Source

Ashton N.K.,University of Idaho | Ireland S.C.,Kootenai Tribe of Idaho | Cain K.D.,University of Idaho
Transactions of the American Fisheries Society

A conservation program developed by regional stakeholders incorporates stock enhancement as one of several approaches to restore an imperiled Burbot Lota lota population native to Idaho and British Columbia. Tagging juvenile fish is pivotal to stock enhancement monitoring; however, limited information is currently available on marks or tags applied to Burbot. We identified six criteria to guide artificial marker selection that are specific to imperiled juvenile fish. A short-term experiment with age-0 Burbot (65-92 mm TL) tested fin clips, freeze brands, visible implant elastomer, passive integrated transponders, and an unmarked control group. At 4 weeks posttagging, no significant differences were found between marking treatments with respect to fish survival (100%), absolute growth rate (0.15 ± 0.06 mm/d), specific growth rate (0.55 ± 0.32 g·g-1·d-1), or condition factor (0.64 ± 0.05). Mean tag retention ranged from 88% to 100%, and no significant differences were detected between treatments. Recognition of dorsal freeze brands differed significantly between two independent tag assessments. Overall, we found no adverse short-term effects and high tag retention in this preliminary trial of seven artificial marks applied to hatchery-reared Burbot. Received September 4, 2012; accepted March 13, 2013. © 2013 Copyright Taylor and Francis Group, LLC. Source

Hardy R.S.,885 W. Kathleen Ave. | Stephenson S.M.,British Columbia Ministry of forests | Neufeld M.D.,British Columbia Ministry of forests | Young S.P.,Kootenai Tribe of Idaho

Burbot Lota lota maculosa numbers in Kootenay Lake and Kootenai River of British Columbia, Idaho, and Montana have diminished due to habitat changes from the construction of Libby Dam. Recent implementation of a conservation strategy included aquaculture to supplement the population using a donor stock from a self-sustaining lake population within the watershed. Evaluation of release strategies using telemetry and mark recapture through hoop netting suggests lake-origin Burbot have adapted to the Kootenai system and selected riverine over lacustrine habitat. Previous telemetry work identified good survival and dispersal of released Burbot, and vast dispersal distance and lacustrine use. However, our analysis of a broader telemetry dataset indicated that only 24% of age 1–4 Burbot were detected in the lake. Recapture hoop net data indicated that Burbot residing in the river have growth and survival rates comparable to the historical population. Spawning of hatchery origin fish was detected at historical riverine spawning locations. Other than later spawn timing, our evaluations suggest lake-origin fish are mimicking movement and habitat use of the historical riverine population. This study, in combination with others, provides evidence that Burbot progeny from lacustrine brood stock can successfully survive, grow, disperse, and spawn in a riverine environment. © 2015 Springer International Publishing Switzerland Source

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