Area use and movement patterns of wild and escaped farmed Atlantic salmon before and during spawning in a large Norwegian river
| Autor: | Eva B. Thorstad, Tomas Sandnes, Thrond O. Haugen, Karina Moe, Eva Marita Ulvan, Tonje Aronsen, Tor F. Næsje |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0106 biological sciences
spawning period SH1-691 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920::Akvakultur: 922 Management Monitoring Policy and Law Aquatic Science Biology 010603 evolutionary biology 01 natural sciences River Namsen Pre spawning introgression risk Aquaculture. Fisheries. Angling Salmo QH540-549.5 Water Science and Technology VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Aquaculture: 922 Ecology 010604 marine biology & hydrobiology farmed escapees within-river movements biology.organism_classification Fishery pre-spawning Fish radio telemetry |
| Zdroj: | Aquaculture Environment Interactions Aquaculture Environment Interactions, Vol 8, Pp 77-88 (2016) |
| Popis: | We compared the within-river movements and distribution of wild and escaped farmed Atlantic salmon Salmo salar before and during spawning in the Namsen river system of Central Norway. A total of 74 wild and 43 escaped farmed salmon were captured at sea, tagged with radio transmitters and released. Based on our examinations, most, if not all salmon (farmed and wild) entering the River Namsen were sexually mature. Farmed salmon entering the river sys- tem had a higher probability than wild individuals of reaching the migration barrier in the upper part of the river, 70 km from the sea. During the pre-spawning and spawning periods, farmed salmon were located mainly in the upper parts (50 to 70 km from the sea), whereas wild salmon were evenly distributed along the entire river during both periods. Consequently, the probability of farmed × wild inter-breeding varied among river sections. Our finding that the distribution of escaped farmed salmon may differ from that of wild salmon and among river sections in the pre- spawning and spawning periods—and that it may also vary over time—must be taken into consid- eration when (1) designing monitoring programs aimed at estimating the proportion of escaped farmed salmon in rivers and (2) when interpreting monitoring results. Furthermore, targeted fish- ing in the river aimed at reducing the number of farmed salmon prior to spawning may be more effective in upper rivers sections, and below major migration barriers. |
| Databáze: | OpenAIRE |
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