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Taylor M.K.,Fish Ecology and Conservation Physiology Laboratory | Hasler C.T.,Fish Ecology and Conservation Physiology Laboratory | Findlay C.S.,University of Ottawa | Lewis B.,Golder Associates | And 4 more authors.
River Research and Applications

There is a growing need to develop quantitative relationships between specific components of river flow and the behavioural responses of fishes. Given this, we tested for an effect of hydrologic parameters on axial swimming muscle electromyograms of bull trout (Salvelinus confluentus) in a large hydropeaking river (river discharge ranging from 0 to 1790m3/s) while controlling for other exogenous factors such as temperature and light intensity. Hourly mean discharge had a significant positive effect (R2=0.13-0.31; depending on the distance from the dam) on swimming muscle activity. Within-hour changes in river flow from 0 to 1045m3/s did not elicit a hyperactive response in bull trout. When a subset of electromyogram transmitters were calibrated to swimming speed, we found there were periods, across a range of river discharges, when bull trout were not actively beating their tails-a behaviour documented in some bottom-dwelling species associated with moving water. Not including these periods of rest, bull trout swam at median hourly speeds of 0.53 body lengths per second. Understanding fish behaviour in the context of their physical environment may help explain population-level responses to hydrologic change. © 2013 John Wiley & Sons, Ltd. Source

Thiem J.D.,Fish Ecology and Conservation Physiology Laboratory | Binder T.R.,Fish Ecology and Conservation Physiology Laboratory | Dawson J.W.,Carleton University | Dumont P.,Ministere des Ressources Naturelles et de la Faune | And 5 more authors.
Endangered Species Research

Spawning migrations of sturgeon have been affected by the construction of dams, which create barriers to migration and have contributed to the imperilment of sturgeon. Although devices have been installed to facilitate the upstream passage of fish at barriers, they have been generally unsuccessful and not designed for sturgeon. We examined fine-scale movements of adult lake sturgeon Acipenser fulvescens during passage through a vertical slot fishway located on the Richelieu River in Quebec, Canada, to determine passage success, passage duration and inter-individual differences in fishway use. Migratory lake sturgeon (n = 107, range 939 to 1625 mm total length [TL]) were captured immediately downstream of the fishway, tagged with passive integrated transponder (PIT) tags and released into the fishway entrance basin over a period of 2 wk (water temperature 11-20°C). An array of 16 PIT antennas acted as gates to enable quantification of movements within the fishway. Volitional entry into the fishway occurred for most individuals (82.2%), 32 individuals successfully ascended the entire fishway, and overall passage efficiency was 36.4%. Sturgeon exhibited an ability to traverse the fishway quickly (minimum duration of 1.2 h upon entry into the fishway); however, the duration of successful passage events was variable (6.2-75.4 h following release). Neither passage duration nor maximum distance of ascent was correlated with TL or water temperature. Passage behaviour was variable, in some cases resulting in cumulative upstream movements 3 times in excess of fishway length. Passage durations through the 2 turning basins were disproportionately longer compared with other basins; however, the activity of individuals within these and other locations remains unknown and represents an important knowledge gap. Collectively, data from this study contribute to understanding how fishways can be used to facilitate the upstream passage of imperilled sturgeon at dams. © Inter-Research 2011. Source

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