Seasonal variations of activity pattern of brown trout (Salmo trutta) in a small stream, as determined by radio-telemetry

in Hydrobiologia (2002), 470(1-3), 195-202

Nine brown trout (27.9-42.8 cm FL, 234-995 g) from the Aisne stream (Belgian Ardenne) were tagged with surgically implanted radio transmitters, and their activity patterns were studied at 10-min intervals ... [more ▼]

Nine brown trout (27.9-42.8 cm FL, 234-995 g) from the Aisne stream (Belgian Ardenne) were tagged with surgically implanted radio transmitters, and their activity patterns were studied at 10-min intervals during twenty-six 24-h cycles from October 1995 to May 1997. The duration and intensity of activity were mainly proportional to water temperature and day length but some differences appeared between individuals. The daily home range in summer was also 3.2 times longer than in winter, and was exploited 2.5 times more intensively. At all seasons, trout were most active at dusk, and seasonal variations in diel patterns consisted mainly in a progressive shift from more crepuscular activity in autumn and winter to more homogenous and intensive activity during spring and summer, but still with a predominance of activity at dusk. This relative consistency of activity rhythm throughout the year was interpreted within the context of foraging risk and efficiency, in view of the scarcity of predators in the Aisne stream, and of drifting macroinvertebrates being consistently more abundant at dusk at all times of the year. However, activity patterns varied substantially between individuals living in different microhabitats, including when fish were investigated on the same day. This suggests that activity patterns are also subordinated to local factors such as habitat structure or abundance of drifting prey. [less ▲]

Monitoring the biodiversity and population ecology of fish in the Belgian Meuse Rivier by the use of fishpasses. A 12-year study at the Visé-Lixhe dam.

Conference (2001, December)

A telemetry study on the clearing capacities of salmonids and rheophilic cyprinids facing small obstacles in Southern Belgian rivers and streams.

Conference (2001, June)

Prédation exercée par des grands cormorans sur des truites radio-marquées. Observations préliminaires dans un petit cours d’eau en Wallonie.

Poster (2001, March)

Seventy years after extinction, Atlantic Salmon (Salmo salar) comes back to the river Meuse in Belgium as a result of the Meuse Salmon 2000 restoration project.

Conference (2000, November)

Relationship between habitat structure and the mobility of brown trout in a small stream.

Conference (2000, September)

Methodological bias in home range and mobility estimates when locating radio-tagged trout, Salmo trutta, at different time intervals

in Aquatic Living Resources (2000), 13(6), 449-454

Radio tracking has been extensively used to enhance our knowledge on the movement and home range of fish in general and salmonids in particular. However, the use of various temporal sampling protocols is ... [more ▼]

Radio tracking has been extensively used to enhance our knowledge on the movement and home range of fish in general and salmonids in particular. However, the use of various temporal sampling protocols is likely to overlook fish movements, and produce experimental artefacts, the amplitude of which is unknown and may compromise comparison of fish behaviours revealed by different protocols. Starting from a day-by-day tracking study of brown treat in Belgian waters (Aisne stream, nine fish, minimum 39 daily locations per fish), we re-examined their home range and mobility, through a subsampling process, as if the fish had been located at longer time intervals (2-14 days). The estimates from subsamples were compared to the original data set in order to quantify the corresponding reduction of accuracy from observed data, and how far this could be predicted on the basis of locating frequency. The results clearly indicate that all intervals longer than one day generally generate substantial biases (reduction of accuracy from 0 to 82% for home range and from 5 to 92% for mobility) but these can be partly corrected through the use of predictive models. This analysis demonstrates that any comparison between studies relying on different locating frequencies can generate some ambiguity when interpreting biological phenomena or geographical differences. (C) 2000 Ifremer/CNRS/INRA/IRD/Cemagref/Editions scientifrques et medicales Elsevier SAS. [less ▲]

Le comportement migrateur des poissons en Wallonie. Caractérisation biologique et implication pour une gestion durable des populations.

Conference (1999, November)

A strategy for a sustainable protection and restoration of endangered-vulnerable riverine fish populations. The barbel (Barbus barbus) case study in Belgium.

Conference (1999)

Etude préliminaire des rythmes nycthéméraux d'activité chez Chrysichthys nigrodigitatus (Pisces, Siluriformes, Claroteidae): influence de l'augmentation de salinité.

in Annales des Sciences Agronomiques du Bénin (1999), 2