References of "Ovidio, Michaël"
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See detailImpact assessment and remediation of anthropogenic interventions on fish populations - (FISHGUARD)
DeBoeck, Gudrun; Blust, Ronny; Todorache, Christian et al

Report (2006)

The disruption of longitudinal river connectivity by man-made obstacles and the stocking of fish communities with non-indigenous species or genotypes threaten the fish fauna of Belgian rivers to various ... [more ▼]

The disruption of longitudinal river connectivity by man-made obstacles and the stocking of fish communities with non-indigenous species or genotypes threaten the fish fauna of Belgian rivers to various extents. Obstacles impede migrations between habitats that are vital for populations, and they may restrict the gene flow between populations, thereby reducing the effective size and genetic diversity of populations and increasing the risk of local extinction. Restocking programs often involve the introduction of non-indigenous genotypes in native populations. Moreover, although stocking programs lead to the temporal and superficial enrichment of local fish communities or gene pools, they generally result in a loss of biodiversity on a regional or international scale through the homogenisation of communities and the breakdown of genetic differentiation between populations. Thus, stocking programs cannot compensate for the loss of free migration by artificial obstructions. The impact of these changes on fish populations remains largely unknown, which complicates the priorisation of spots to preserve and spots to restore. Here, we present an integrated study on Belgian waters, both in Flanders and Wallonia, which analyses fish communities, gene flow and migration patterns in the field, as well as the swimming and leaping performances of fishes under controlled conditions. [less ▲]

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See detailMovement patterns, spatial distribution and depth preference by individual whitefish, Coregonus lavaretus in a small artificial lake
Ovidio, Michaël ULg; Neus, Yvan ULg; Rimbaud, Gilles ULg et al

in Folia Zoologica (2006), 55(4), 375-385

Using manual acoustic tracking our study quantified (1) the spatial distribution (2) the movement patterns and (3) the depth preference of adult whitefish, Coregonus lavaretus in it small artificial lake ... [more ▼]

Using manual acoustic tracking our study quantified (1) the spatial distribution (2) the movement patterns and (3) the depth preference of adult whitefish, Coregonus lavaretus in it small artificial lake of eastern Belgium were the species was introduced in 1978 for recreational fishing. From June to October 2004, n=6 C. lavaretus (LF 285-519 mm) were tracked (pingers and depth sensor transmitters) from a small boat over periods ranging from 98 to 108 days in Robertville Lake (elevation: 490 m; area: 63 ha max. depth: 47 in). Whitefish were consistently mobile but showed quite variable lake use patterns. Two individuals traveled the entire length and breadth of the lake, whereas others remained in movement in the deep zone in the middle part of the lake or near the retaining darn wall. Whitefish occupied positions in the water column ranging front 2.6 to 27.0 m (mean 12.7 +/- 5.6 m) that varied depending on individuals. This first study on individual whitefish behaviour provides a better understanding of the behavioural ecology of the species in small artificial lake. [less ▲]

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See detailMovements and depth utilisation by the whithefish Coregonus lavaretus and Coregonus peled in a small artificial lake in eastern Belgium.
Ovidio, Michaël ULg; Legrain, Fanny; Prévost, Vincent et al

Poster (2005, June)

Using manual acoustic tracking our study quantified (1) the spatial distribution (2) the movement patterns and (3) the depth preference of adult whitefish in a small artificial lake of eastern Belgium ... [more ▼]

Using manual acoustic tracking our study quantified (1) the spatial distribution (2) the movement patterns and (3) the depth preference of adult whitefish in a small artificial lake of eastern Belgium were the species was introduced in 1978 for recreational fishing. From June to October 2004, n=6 C. lavaretus (LF 285-519 mm) were tracked (pingers and depth sensor transmitters) from a small boat over periods ranging from 98 to 108 days in Robertville Lake (elevation: 490 m; area: 63 ha; max. depth: 47 m). Whitefish were consistently mobile but showed quite variable lake use patterns. Two individuals traveled the entire length and breadth of the lake, whereas others remained in movement in the deep zone in the middle part of the lake or near the retaining dam wall. Whitefish occupied positions in the water column ranging from 2.6 to 27.0 m (mean 12.7 m ± 5.6 m) that varied depending on individuals. This first study on individual whitefish behaviour provides a better understanding of the behavioural ecology of the species in small artificial lake. [less ▲]

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See detailHabitat use of juvenile Atlantic salmon (Salmo salar): the relation between physical variables and individual mobility.
Roy, Mathieu; Ovidio, Michaël ULg; Enders, Eva et al

Conference (2005, May)

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See detailA 12-year study of the upstream migration of Anguilla anguilla in a fish-pass in the river Meuse reveals a dramatic decline of the stock in Belgium.
Philippart, Jean-Claude ULg; Ovidio, Michaël ULg; Sonny, Damien

Conference (2005, April)

From 1992 to 2004 upstream migrating eels were collected in a trap (0,5 cm mesh size) installed at the top of a small pool-type fish-pass at the Visé-Lixhe dam (built in 1980 for navigation purposes and ... [more ▼]

From 1992 to 2004 upstream migrating eels were collected in a trap (0,5 cm mesh size) installed at the top of a small pool-type fish-pass at the Visé-Lixhe dam (built in 1980 for navigation purposes and hydropower generation; height : 8,2 m; not equipped with a ship-lock) on the international River Meuse near the Dutch -Belgium border (290 km from the North Sea; width: 200 m; mean annual discharge: 238 m3/s; summer water temperature 21-26°C).The trap in the fish-pass was checked continuously (three times a week) over the migration period from March to September each year, except in 1994. We caught a total number of 32157 eels (biomass 1,955 kg) with a size from 14 cm to 85 cm and a mean value of 31,6 cm corresponding to yellow eels. The study based on a constant year-to-year sampling effort revealed a regular decrease of the annual catch from a maximun of 5613 fish in 1992 to a minimum of 423 in 2004. This demographic trend is fitted by the equation: number per year = 5.614 - 299 t, where t is time in years with 1992 as year 1. According to this model, the upstream migrating yellow eelstock in the Belgian Meuse should drop to near zero within the next ten years, as an expression of a collapsing recruitment of glass eels in the estuary in the Netherlands. In the discussion of these results, we examine the possible role of two other factors on the decrease over time of the number of yellow eels caught in the fish-pass. i) the effect of environmental variables (river discharge, water temperature and dissolved oxygen content) on the timing and intensity of upstream migration waves and ii) the existence and use of alternative migration routes. [less ▲]

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See detailThe reconstruction of an Atlantic salmon population in the Belgian River Meuse basin. First success and new threats.
Philippart, Jean-Claude ULg; Ovidio, Michaël ULg; Frank, Vincent et al

Conference (2005, April)

A 'Meuse Salmon' project aiming at restoring an Atlantic salmon run in the River Meuse basin was put forward in 1983 (after the discovery of several 'sea trout' in the Meuse near Liège) and started ... [more ▼]

A 'Meuse Salmon' project aiming at restoring an Atlantic salmon run in the River Meuse basin was put forward in 1983 (after the discovery of several 'sea trout' in the Meuse near Liège) and started officially in 1987 as a contribution of Wallonia to the European Year of Environment. In the course of this programme, most dams (3-8 m in height) obstructing the canalised River Meuse in Belgium and The Netherlands have been fitted with modern fish-ways in order to restore the free circulation of diadromous fish species. A second facet of the Salmon Meuse programme consisted in restocking salmonid streams in the Belgian Ardennes with hatchery reared salmon parr and smolt (maximum 200.000 fish per year) from foreign origins (Scotland, Ireland and France). Returning adult salmon have been scientifically recorded in the Meuse in The Netherlands (estuary and lower course) since 1994 but only since the year 2002 in Belgium: 13 (61-79 cm FL) fish in 2002 and 2 (71-76 cm FL) fish in 2003 caught mostly (13 fish) in a new big fish-pass at the Visé-Lixhe dam and (2 fish) in the River Berwinne, a small tributary of the Meuse known as the last spawning place for S. salar in Belgium in the 1920's. Female and male returning salmon in 2002 were successfully artificially reproduced in order to build a captive freshwater brood stock to be used for production of parrs and smolts of the new Meuse strain next autumn. The communication briefly reports on the progress of the program as concerns the salmon culture for stocking in Wallonia, the population dynamics of stocked parrs in nursery rivers, the patterns of upstream and downstream migration of salmon in the Belgian Meuse and its tributaries and the new challenges to meet (impact on salmon of rising water temperature, development of power generation, increasing predation on smolts by piscivorous birds). [less ▲]

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See detailExperiences and results with telemetry track-ing of smolts and parrs in Belgium
Ovidio, Michaël ULg

Scientific conference (2005, February)

Abstract 1. History of the Meuse salmon project in Walloon Region A 'Meuse Salmon' project aiming at restoring an Atlantic salmon run in the River Meuse basin was put forward in 1983 (after the discovery ... [more ▼]

Abstract 1. History of the Meuse salmon project in Walloon Region A 'Meuse Salmon' project aiming at restoring an Atlantic salmon run in the River Meuse basin was put forward in 1983 (after the discovery of several 'sea trout' in the Meuse near Liège) and started officially in 1987 as a contribution of Wallonia to the European Year of Environment. In the course of this programme, most dams (3-8 m in height) obstructing the canalised River Meuse in Belgium and The Netherlands have been fitted with modern fish-ways in order to restore the free circulation of diadromous fish species. A second facet of the Salmon Meuse programme consisted in restocking salmonid streams in the Belgian Ardennes with hatchery reared salmon parr and smolt (maximum 200.000 fish per year) from foreign origins (Scotland, Ireland and France). Returning adult salmon have been scientifically recorded in the Meuse in The Netherlands (estuary and lower course) since 1994 but only since the year 2002 in Belgium: 13 (61-79 cm FL) fish in 2002 and 2 (71-76 cm FL) fish in 2003 caught mostly (13 fish) in a new big fish-pass at the Visé-Lixhe dam and (2 fish) in the River Berwinne, a small tributary of the Meuse known as the last spawning place for S. salar in Belgium in the 1920's. In 2004 returning adult salmon were not recorded in Belgian waters. Female and male returning salmon in 2002 were successfully artificially reproduced in order to build a captive freshwater brood stock to be used for production of parrs and smolts of the new Meuse strain. In 2006 a new salmon farming center will be inaugurated in Erezée (River Aisne) and will produce 200.000 juvenile Atlantic Salmon per year. 2. Monitoring of the downstream migration of smolts As the return of adult A. salmon in spawning tributaries will be permitted by the building of efficient fish passes, the success of the Meuse salmon project will mainly be influenced by the potentiality of smolts to migrate downstream. Hydroelectric power plants are frequent in the River Meuse and in its tributaries and new installations are scheduled in the next years. In wallonia, the dynamic of the downstream migration of A. salmon smolts was essentially studied in a small downstream fish trap located in the river Samson, a small tributary of the R. Meuse. Precious informations on the timing of migration and on the characteristics of the migrants were annually collected since the late eighties. In 2000, a downstream migration trap was experimented in the Visé-Lixhe dam in the main course of the river Meuse. Results bring additional information on the potential cumulate mortality between the River Samson and the Lixhe dam using mark-recapture techniques. Currently our objective is to study the entire dynamic of the downstream migrations of the smolts from the tributaries, to the Belgian border using biotelemetry techniques. A first successful experiment was carried out on 2004 on a single sea trout smolt individual that was continuously radio-tracked from Liège to Lixhe from a small boat. This spring, a similar experiment on a greater scale (up to 20 tracked individuals) will be carried out in the river Meuse and its tributaries. The communication briefly presents the different results of the monitoring of the downstream migration of smolts in Wallonia and give informations on the techniques and methodologies employed as well as new challenges for the future. An additional part of the communication reports on results of a parallel research axis as concerns the behavioural ecology of A. salmon parrs using radio telemetry. [less ▲]

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See detailLong range seasonal movements of northern pike (Esox lucius L.) in the barbel zone of the River Ourthe (River Meuse basin, Belgium).
Ovidio, Michaël ULg

in Aquatic telemetry: advances and applications (2005)

In order to study the annual activity cycle and reproductive ecology of northern pike (Esox lucius L.) in the River Ourthe (Belgian Ardenne), 6 fish (579-742mm FL, 1605-4090g, 2 females and 4 males) were ... [more ▼]

In order to study the annual activity cycle and reproductive ecology of northern pike (Esox lucius L.) in the River Ourthe (Belgian Ardenne), 6 fish (579-742mm FL, 1605-4090g, 2 females and 4 males) were captured by electric fishing in November 2000 and January 2001. They were surgically implanted with a radio-transmitter and tracked for 149 to 349 days in a 30-km river stretch. During the pre-spawning period in winter, most movements were between distinct holding areas spaced from 40 to 550 m. All the pike began the upstream spawning migration between 8 February and 30 March 2001, when the mean water temperature varied from 6.7°C to 8.7 °C and the water flow from 52 to 199 m3s-1. The six pike travelled upstream, over distances ranging from 0.75 km to 15.7 km to reach their potential spawning sites. Pike arrived on their potential spawning sites between the 13 February and the 02 April 2001 and remained there from 5 to 25 days when the daily mean water temperature ranged from 2.9 to 10.0 °C. The six pike moved downstream after spawning and showed similar behaviour to those observed prior to spawning, but the distances between holding areas were more extended than during the winter pre-spawning period. When considering the entire tracking period, the longitudinal extension of the activity domains ranged 1 421 to 24 798 m (mean 12,050 m). This exploratory study provided original observations on northern pike movements in a barbel zone of the River Meuse basin. Results contrasted with the widely established view of pike being a sedentary predator and provides data on its behaviour throughout the annual cycle. [less ▲]

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See detailTurbulence et patron d’utilisation de l’habitat du saumon atlantique juvénile.
Roy, Mathieu; Ovidio, Michaël ULg; Enders, Eva et al

Conference (2004, May)

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See detailUtilisation de l’habitat par la truite commune. Apport de la biotélémétrie.
Ovidio, Michaël ULg

Conference (2004, January)

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See detailTurbulence et patron d’utilisation de l’habitat du saumon atlantique juvénile
Roy, M. L.; Ovidio, Michaël ULg; Hallot, Eric ULg et al

Scientific conference (2004)

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See detailEffects of a micro hydroelectric power plant upon population abundance, mobility and reproduction behaviour of European grayling T. thymallus and brown trout S. trutta in a salmonid river
Ovidio, Michaël ULg; Paquer, Frédéric ULg; Capra, Hervé et al

in Garcia de Jalon, Diego; Vizcaino Martinez, Pilar (Eds.) International Symposium on Ecohydraulics. Aquatic habitat: Analysis & Restoration (2004)

This study examines the potential effects of a new micro hydroelectric power plant (MHPP) on the behaviour (habitat use, movements) and population abundance of European grayling (T. thymallus) and brown ... [more ▼]

This study examines the potential effects of a new micro hydroelectric power plant (MHPP) on the behaviour (habitat use, movements) and population abundance of European grayling (T. thymallus) and brown trout (S. trutta) in the Lhomme (Belgian Ardennes). Thirteen grayling and five brown trout were captured before their spawning period and were manually radio-tracked up to 6 times a week. Population density and biomass were estimated into two different sampling sectors with electric fishing, before and after the MHPP started up. The mobility patterns of grayling and trout in the reach of the river Lhomme influenced by the MHPP strongly contrasted with results obtained in an undisturbed river of the same type in the Belgian Ardennes. Movements were mostly restricted and rarely increased during the spawning period. Spawning took place, but was disturbed by hydropeakings. The population biomass of grayling and trout decreased by 61 % and 23 % respectively, five months after the start-up of the MHPP exploitation. [less ▲]

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See detailSpawning movements of European grayling Thymallus thymallus in the River Aisne (Belgium)
Ovidio, Michaël ULg; Parkinson, Denis; Sonny, Damien et al

in Folia Zoologica (2004), 53(1), 87-98

In three consecutive years (1998 to 2000), 20 adult grayling Thymallus thymallus (L.) (FL +/- SD: 326 +/- 43 mm) were radio-tracked during circum reproduction period (February to May) in the River Aisne ... [more ▼]

In three consecutive years (1998 to 2000), 20 adult grayling Thymallus thymallus (L.) (FL +/- SD: 326 +/- 43 mm) were radio-tracked during circum reproduction period (February to May) in the River Aisne, Belgium. Before the spawning period, grayling remained consistently in the pool-riffle sequence in which they had been captured. Pre-spawning migration time extended from 7 to 29 March. Distances travelled during the spawning migration ranged from 70 to 4980 in (mean +/- S.E.: 1234 +/- 328 m). Spawning migrations stalled under conditions of decreasing water level and increasing water temperature in a thermal range (daily mean Tdegrees) from 5 to 8 degreesC. Spawners remained from 1 to 31 days (mean +/- S.D.: 10.4 +/- 9.8 days) at the spawning grounds and performed a post-spawning homing from 28 March to 18 April in decreasing water flow and in a thermal range (daily mean Tdegrees) from 7 to 11 degreesC. This study demonstrates that migration patterns of grayling are similar between years, but with a timing adjusted as a response to annual variations of the hydroclimatic conditions. [less ▲]

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See detailLong range seasonal movements of northern pike (Esox lucius L.) in the barbel zone of the River Ourthe (River Meuse basin, Belgium).
Ovidio, Michaël ULg; Philippart, Jean-Claude ULg

Conference (2003, June)

In order to study the annual activity cycle and reproductive ecology of northern pike (Esox lucius L.) in the River Ourthe (Belgian Ardenne), 6 fish (579-742mm FL, 1605-4090g, 2 females and 4 males) were ... [more ▼]

In order to study the annual activity cycle and reproductive ecology of northern pike (Esox lucius L.) in the River Ourthe (Belgian Ardenne), 6 fish (579-742mm FL, 1605-4090g, 2 females and 4 males) were captured by electric fishing in November 2000 and January 2001. They were surgically implanted with a radio-transmitter and tracked for 149 to 349 days in a 30-km river stretch. During the pre-spawning period in winter, most movements were between distinct holding areas spaced from 40 to 550 m. All the pike began the upstream spawning migration between 8 February and 30 March 2001, when the mean water temperature varied from 6.7°C to 8.7 °C and the water flow from 52 to 199 m3s-1. The six pike travelled upstream, over distances ranging from 0.75 km to 15.7 km to reach their potential spawning sites. Pike arrived on their potential spawning sites between the 13 February and the 02 April 2001 and remained there from 5 to 25 days when the daily mean water temperature ranged from 2.9 to 10.0 °C. The six pike moved downstream after spawning and showed similar behaviour to those observed prior to spawning, but the distances between holding areas were more extended than during the winter pre-spawning period. When considering the entire tracking period, the longitudinal extension of the activity domains ranged 1 421 to 24 798 m (mean 12,050 m). This exploratory study provided original observations on northern pike movements in a barbel zone of the River Meuse basin. Results contrasted with the widely established view of pike being a sedentary predator and provides data on its behaviour throughout the annual cycle. [less ▲]

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See detailCaractérisation et utilisation du micro-habitat du saumon atlantique (Salmo salar) selon la stucture turbulente del'écoulement.
Brown, Julie; Boyer, Claudine; Enders, Eva et al

Conference (2003, May)

Detailed reference viewed: 16 (5 ULg)