References of "Lamouroux, Nicolas"
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See detailProbability of detection and positioning error of a hydro acoustic telemetry system in a fast-flowing river: intrinsic and environmental determinants
Bergé, Julien; Capra, Hervé; Pella, Hervé et al

in Fisheries Research (2012), 125-126

In situ fixed acoustic telemetry methods make it possible to study simultaneously the detailed movements of individual fish and their relationship to the environment, but the properties of these methods ... [more ▼]

In situ fixed acoustic telemetry methods make it possible to study simultaneously the detailed movements of individual fish and their relationship to the environment, but the properties of these methods is little known in harsh physical conditions. We examined the probability of tag detection by the system and the positioning error for detected tags of an existing telemetry system installed with 32 fixed hydrophones in a reach of the fast-flowing Rhône River in France. The reach was 1.8 km long and had heterogeneous thermal and hydraulic conditions described by a two-dimensional hydraulic model. We compared positions detected by the system with true positions estimated using a tachometer or a differential GPS, for various sets of experimental tag emissions. We analyzed how the probability of detection and the positioning error were affected by user-defined variables and three groups of environmental variables describing the configuration of the hydrophones around tag position, the physical environment at tag position and the reception quality. Tag emissions from the center channel had an average probability of detection (40-50%) higher than emissions originating from positions close to the banks, and were positioned with smaller average errors (3-5 m). The probability of detection of emissions typically varied between near 0% and 80% with configuration variables (density of surrounding hydrophones and location of tag relative to the hydrophones) and also decreased in the presence of coarse substrate. The positioning error was mainly reduced when user-defined variables of the triangulation software were set by an expert user. Configuration variables also influenced the positioning error with weaker effects than those observed for detection probability. [less ▲]

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See detailDescription of Fish Mobility and Habitat Use in a Large Regulated Fast Flowing River (the Rhône River, France) Using Fine Scale Acoustic Tracking
Bergé, Julien; Capra, Hervé; Pella, Hervé et al

Conference (2011, September)

Understanding fine scale behavioral responses of fish to changes in abiotic characteristics of streams (in term of flow and water temperature) is an interesting innovative issue to improve river ... [more ▼]

Understanding fine scale behavioral responses of fish to changes in abiotic characteristics of streams (in term of flow and water temperature) is an interesting innovative issue to improve river management of highly disturbed large rivers. Acoustic telemetry system have become an essential technology for such studies involving continuous (per second) and accurate tracking of fish movements. In the Rhône River (France), important hydrology and thermal contrasts are mainly explicated by the succession of dams and nuclear power plant from the Leman Lake (Switzerland). In this context, it is likely that fish are compelled to adapt their behaviour and their habitat selection in this changing environment. In order to test this hypothesis, a fixed acoustic telemetry survey was performed in the Rhône River during summer 2009 in front of the Bugey nuclear power plant which released warmed water within the river. A study site of 1.8 km long and 140 m wide was monitored using 32 hydrophones developed by HTI® (Hydroacoustic Technology Inc.). Sixty two fish mainly belonging to three species barbel (Barbus barbus), chub (Leuciscus cephalus) and wels catfish (Silurus glanis) were marked with acoustic tags (307 KHz; pulse rate ~ 3 sec.) and followed continuously during 89 days. Fish positions were coupled with a 2D hydraulic model to obtain main physical characteristics encountered by fish such as flow velocity, water depth, water temperature and substrate. The accuracy of the telemetry system was checked and a positional error less than 4 m was found in the channel (detection efficiency of 50 %) and less than 8 meters along the banks (detection efficiency of 20 %). Behavioral responses of fish were investigated through the individual mobility and activity during selected phases of flow (increase, decrease and stability) and water temperature changes (imposed by both warm water plumes and the rapid transition of deep cold waters from the Leman Lake discharged within the river). Mobility and activity of fish were particularly studied to determine the amount of movement associated with a change of abiotic conditions. The separate effects of each environmental factors on behavioral responses of fish were studied and interactions between factors were analyzed to highlight potential synergistic or antagonistic effects. Finally, movement rules (i.e. individual movement decisions in a particular surrounding environment) were analyzed to determine the role of perception of the environment by fish (i.e. how the fish feel the changes in physical habitat) in the use of space. [less ▲]

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