Störs laxens lekvandring i en kraftverkspåverkad älvsträcka?
The upstream spawning migration of Atlantic salmon (Salmo salar) at the confluence area between the power-station outlet and the bypass-channel in river Umeälven (flow 430 m3s-1) was compared in 2004 and 2005, two years with different experimental flow-regimes. In 2004 the water flow in the bypas...
| Autor principal: | |
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| Formato: | Otro |
| Lenguaje: | sueco sueco |
| Publicado: |
2006
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| Materias: | |
| Acceso en línea: | https://stud.epsilon.slu.se/12406/ |
| _version_ | 1855572057451921408 |
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| author | Lundgren, Johan |
| author_browse | Lundgren, Johan |
| author_facet | Lundgren, Johan |
| author_sort | Lundgren, Johan |
| collection | Epsilon Archive for Student Projects |
| description | The upstream spawning migration of Atlantic salmon (Salmo salar) at the confluence
area between the power-station outlet and the bypass-channel in river Umeälven (flow 430
m3s-1) was compared in 2004 and 2005, two years with different experimental flow-regimes.
In 2004 the water flow in the bypass-channel was altered during the day with increased
flows during the nights while the water flow in 2005 mainly was altered between the
weekdays and weekends. Salmon showed altered migratory behaviour in this confluence
area, assessed with telemetry (n=116) and echo-sounding, with up- or downstream responses
depending on flow-changes in both the bypass and the power station outlet. Increased
turbine flow through the power-station generally attracted salmon into the tunnel outlet area
while increased spill-flows facilitated salmon to enter the bypass. Echo-sounding in the
confluence area showed an increased swimming activity up- and downstream due to time in
the day and flow-rates through the tunnel outlet. No changes in activity could be detected
due to increasing or decreasing flow through the hydro-power facility. About 70 % of the
registrated movements originated from salmon swimming downstream and fish were found
across the whole outlet channel and down to 40 m depth. In 2004 the spill-flows were
regulated on daily basis and caused elevated movements of salmon and a prolonged stay of
salmon at the confluence area compared to year 2005 with weekly spill-flow patterns. In
addition, the migration success of salmon to the fish-ladder 32 km upstream the river mouth
was lower (21 % vs. 44 %) and travel-time higher (42,6 day vs. 35,7 day) in 2004 than 2005,
respectively. The overall results demonstrate the negative effects of rapidly changing flows
on salmon upstream migration success. |
| format | Otro |
| id | RepoSLU12406 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish swe |
| publishDate | 2006 |
| publishDateSort | 2006 |
| record_format | eprints |
| spelling | RepoSLU124062017-10-30T12:34:08Z https://stud.epsilon.slu.se/12406/ Störs laxens lekvandring i en kraftverkspåverkad älvsträcka? Lundgren, Johan Fisheries and aquaculture - General aspects The upstream spawning migration of Atlantic salmon (Salmo salar) at the confluence area between the power-station outlet and the bypass-channel in river Umeälven (flow 430 m3s-1) was compared in 2004 and 2005, two years with different experimental flow-regimes. In 2004 the water flow in the bypass-channel was altered during the day with increased flows during the nights while the water flow in 2005 mainly was altered between the weekdays and weekends. Salmon showed altered migratory behaviour in this confluence area, assessed with telemetry (n=116) and echo-sounding, with up- or downstream responses depending on flow-changes in both the bypass and the power station outlet. Increased turbine flow through the power-station generally attracted salmon into the tunnel outlet area while increased spill-flows facilitated salmon to enter the bypass. Echo-sounding in the confluence area showed an increased swimming activity up- and downstream due to time in the day and flow-rates through the tunnel outlet. No changes in activity could be detected due to increasing or decreasing flow through the hydro-power facility. About 70 % of the registrated movements originated from salmon swimming downstream and fish were found across the whole outlet channel and down to 40 m depth. In 2004 the spill-flows were regulated on daily basis and caused elevated movements of salmon and a prolonged stay of salmon at the confluence area compared to year 2005 with weekly spill-flow patterns. In addition, the migration success of salmon to the fish-ladder 32 km upstream the river mouth was lower (21 % vs. 44 %) and travel-time higher (42,6 day vs. 35,7 day) in 2004 than 2005, respectively. The overall results demonstrate the negative effects of rapidly changing flows on salmon upstream migration success. Beteendet hos lekvandrande lax (Salmo salar) i sammanflödesområdet i Umeälvens nedre del (medelflöde 430 m3s-1), mellan turbinutlopp och den flödesreglerade ”gamla älvfåran”, jämfördes för åren 2004 och 2005. Flödet i torrfåran har under 2004 varierat över dygnet, med högre flöden under natten och lägre på dagen medan det under 2005 i huvudsak varierade mellan veckodagar och helger. Radiomärkta lekvandrande lax (n=116 märkta fiskar) och ekolodning i tunnelutloppsområdet visade att laxen vandrade både uppoch nedströms i relation till flödesändringar i både gamla älvfåran och kraftverket. Generellt sökte sig laxen mot högsta vattenflödet från turbinutloppet medan en ökning av spillflödet i gamla älvfåran lockade laxen i denna riktning som efter c. 8 km leder till fisktrappan i Norrfors damm. Efter registrering i fisktrappan släpps de vidare för vandring till lekområden i Vindelälven. Ekolodning i sammanflödesområdet påvisades en högre simaktivitet hos lax beroende på tid på dygnet samt flöde genom kraftverket, däremot inte efter förändrade kraftverksflöden. Omkring 70 % av de registrerade förflyttningarna var efter lax som vandrade nedströms och dessa har registrerats över hela utloppskanalens bredd och ner till 40 m djup. 2004 reglerades flödet i torrfåran på dygnsbasis, vilket orsakade fler förflyttningar, s.k ”jojo” simningar och en ökning av den tid som laxen tillbringade i sammanflödesområdet jämfört med 2005 då flödet reglerades på veckobasis. Samtidigt som vandringstiden för laxen till laxtrappan 32 km uppströms älvmynningen var längre år 2004 (42,6 dagar vs. 35,7 dagar) så var också vandringsframgången lägre jämfört med 2005 (21 % vs. 44 %). Resultaten visar på en negativ effekt på laxens lekvandring till följd av låga vattenflöden och snabba flödesändringar i torrfåran 2006-09-19 Other NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/12406/1/lundgren_j_171030.pdf Lundgren, Johan, 2006. Störs laxens lekvandring i en kraftverkspåverkad älvsträcka?. UNSPECIFIED, Umeå. Umeå: (NL, NJ) > Dept. Of Aquatic Resources <https://stud.epsilon.slu.se/view/divisions/OID-135.html> urn:nbn:se:slu:epsilon-s-8422 swe |
| spellingShingle | Fisheries and aquaculture - General aspects Lundgren, Johan Störs laxens lekvandring i en kraftverkspåverkad älvsträcka? |
| title | Störs laxens lekvandring i en kraftverkspåverkad älvsträcka? |
| title_full | Störs laxens lekvandring i en kraftverkspåverkad älvsträcka? |
| title_fullStr | Störs laxens lekvandring i en kraftverkspåverkad älvsträcka? |
| title_full_unstemmed | Störs laxens lekvandring i en kraftverkspåverkad älvsträcka? |
| title_short | Störs laxens lekvandring i en kraftverkspåverkad älvsträcka? |
| title_sort | störs laxens lekvandring i en kraftverkspåverkad älvsträcka? |
| topic | Fisheries and aquaculture - General aspects |
| url | https://stud.epsilon.slu.se/12406/ https://stud.epsilon.slu.se/12406/ |