References of "Coeck, Johan"
     in
Bookmark and Share    
Peer Reviewed
See detailEuropean silver eel (Anguilla anguilla L.) migration behaviour in a highly regulated shipping canal
Verhelst, Pieterjan; Baeyens, Raf; Buysse, David et al

Conference (2017, June)

Over the last 40 years, Anguilla species in the northern hemisphere have shown a strong decline in recruitment. Due to a 98% recruitment decline, the European eel is now classified as critically ... [more ▼]

Over the last 40 years, Anguilla species in the northern hemisphere have shown a strong decline in recruitment. Due to a 98% recruitment decline, the European eel is now classified as critically endangered according to the IUCN Red List. To aid conservation and recovery of European eel populations, the European Union recently adopted a Council Regulation which imposes a management system that ensures 40% escapement of the spawning stock biomass, defined as the best estimate of the theoretical escapement rate if the stock were completely free of anthropogenic influences. Various causes likely contribute to the eel decline (e.g. pollution, human-introduced parasites, changes in ocean climate, habitat deterioration…), but habitat fragmentation by migration barriers that prevent the movement of silver eels between freshwater and the sea is probably one of the most important bottlenecks. During the last decades, a substantial number of canals has been developed, creating new habitat for eels. However, eel migration and potential obstacles in these systems are still underexplored. In this study, we tracked 131 European eels (Anguilla anguilla L.) from October 2014 till March 2017 in the Belgian Albert Canal with acoustic telemetry. The 130-km long canal is on average 86 m wide, 5 m deep and functions as a shipping route between the rivers Schelde and Meuse. The canal has a highly regulated water flow and six shipping locks to overcome the 56-m fall, which may have a negative impact on silver eel escapement. Indeed, we found significant delays (i.e. periods with a significantly prolonged residence time) and a ca 50% lower swimming speed near shipping locks compared to riverine conditions. Depending on nothing but their accumulated fat for migration to their spawning grounds, delays can seriously impact eels by wasting precious energy resources needed for a successful trans-Atlantic migration. [less ▲]

Detailed reference viewed: 27 (3 ULiège)
Full Text
Peer Reviewed
See detailMobility of individual roach Rutilus rutilus (L.) in three weir-fragmented Belgian rivers
Geeraerts, Caroline; Ovidio, Michaël ULiege; Verbiest, Hilde et al

in Hydrobiologia (2007), 582

Adult roach Rutilus rutilus (L.) (N = 24; 19.9-36.1 cm FL) from three highly fragmented Belgian rivers were tagged with surgically implanted radio transmitters. Their seasonal movements were observed from ... [more ▼]

Adult roach Rutilus rutilus (L.) (N = 24; 19.9-36.1 cm FL) from three highly fragmented Belgian rivers were tagged with surgically implanted radio transmitters. Their seasonal movements were observed from March to August 2004 (circum reproduction period) in river stretches delimited by two physical barriers. In the three rivers, roach displayed similar patterns of movements which were mainly influenced by the date of observation (movements increased in late April-May) and water temperature (travel distances were more important when water temperature ranged between 10 degrees C and 14 degrees C). Roach sometimes cleared physical obstacles. The mean distances travelled in each river were relatively short (max. 2.5 km) and mainly influenced by the length of the study reach, which was delimited by physical barriers. [less ▲]

Detailed reference viewed: 87 (13 ULiège)
Peer Reviewed
See detailMobility and spawning migration of roach in three fragmented rivers in Belgium
Geeraerts, Caroline; Verbiest, Hilde; Buysse, David et al

Conference (2006, June)

Detailed reference viewed: 30 (3 ULiège)
Full Text
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 ▲]

Detailed reference viewed: 81 (15 ULiège)