Migration behaviour of Atlantic salmon smolts (Salmo salar L.) in a short and highly fragmented gravel-bed river stretch
Renardy, S.; Colson, D.; Benitez, J.-P.; Dierckx, A.; Goffaux, D.; Sabbe, J.; Rabouan, A.; Detrait, O.; Matondo, B.N.; Sonny, D.; Ovidio, M. (2022). Migration behaviour of Atlantic salmon smolts (Salmo salar L.) in a short and highly fragmented gravel-bed river stretch. Ecol. Freshw. Fish. 31(3): 499-514. https://dx.doi.org/10.1111/eff.12646
In: Ecology of freshwater fish. John Wiley & Sons ltd.: Copenhagen. ISSN 0906-6691; e-ISSN 1600-0633, more
|  |
| Keyword |
Salmo salar Linnaeus, 1758 [WoRMS]
|
| Author keywords |
Archimedes screw; behavioural tactic; hydraulics; hydroelectricity; migration barrier; mortality |
| Authors | | Top |
|
- Goffaux, D., more
- Sabbe, J., more
- Rabouan, A., more
- Detrait, O.
|
|
| Abstract |
The succession of migration barriers and different turbine types during downstream migration impede Atlantic salmon (Salmo salar L.) smolts from reaching the sea in time but is poorly studied. We investigated the isolated and cumulative impacts of 14 consecutive migration barriers (MBs) on downstream migration of 200 radio-tagged smolts over an 18.9 km stretch of gravel-bed river, by equipping five MBs with automated radio listening stations. At the level of isolated barriers, median research times (i.e. time between the first and the last detection upstream of a MB) varied between 0.1 and 0.7 h. The median crossing delays (i.e. time between the first detection upstream and the first detection downstream of a MB) varied between 1 and 2.9 h. Considering successive MBs, median cumulative crossing delays varied between 2.6 and 32.1 h and increased with the number of MBs. We observed a global mortality rate between 33% and 76%, increasing with the distance travelled and the associated number of MBs. Only 48% of the migrating smolts reached the end of the studied river stretch. Results suggest that the dynamics of the smolt downstream migration over this short highly fragmented stretch had a significant effect in terms of delays, mortalities and seaward escapement rate. |
|
