Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Upstream fishway performance by Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) spawners at complex hydropower dams –is prior experience a success criterion?
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).ORCID iD: 0000-0002-9683-8080
Norsk institutt for naturforskning NINA.
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).ORCID iD: 0000-0002-3191-7140
Multiconsult.
Show others and affiliations
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Passage of hydropower plants by upstream-migrating salmonid spawners is associated with increased mortality, delays, injuries and reduced migration success, and consequently the need for a more comprehensive understanding of fish behavior downstream of dams is widely recognized. Studies of passage typically involve tagging fish, and in many cases, the fish used in these studies are caught in the fishways, and hence have prior experience negotiating them. In this study, we studied fishway passage of tagged landlocked Atlantic salmon (Salmo salar) in the River Klarälven, Sweden and brown trout (Salmo trutta) in the River Gudbrandslågen, Norway, and the influence of prior experience on passage success in 2012 and 2013. In the River Klarälven, fishway efficacy varied from 18 (2012) to 88% (2013). Most salmon (81%) entered the fishway trap on days without spill, and salmon moved from the turbine area to the spill zone when there was spill, with small individuals showing a stronger reaction than large fish. Analysis of fish with and without prior trap experience showed that a higher percentage of the “naïve” fish (70% of salmon and 43% of the trout) entered the fishway traps than the “experienced” ones (25% of the salmon and 15 % of the trout). Delays for fish that entered the trap ranged from 3-70 days for salmon and 2-47 days for trout, and there was no difference in median delay between naïve and experienced fish for each species. Manual positioning of radio-tagged salmon revealed that 11% of the naïve fish and 50% of the experienced fish ceased migration after tagging and release. In addition, a greater percentage of the salmon that were captured, marked and released in the lake attempted to enter the fishway (70%) than lake-caught salmon that were also transported 10km to the stream before release (33%). The data based on manual positioning and lake caught salmon indicate that differences in behavior of naïve and experienced individuals are likely stress-related. Moreover, our results suggest that estimates of fishway efficacy using fish with prior fishway experience may be biased, and based on our study, efficacy is underestimated.

Keywords [en]
Atlantic salmon, brown trout, migration, spawners, spawning, fishways, fish passage solutions, delay, hydropower
National Category
Biological Sciences
Research subject
Biology
Identifiers
URN: urn:nbn:se:kau:diva-71325OAI: oai:DiVA.org:kau-71325DiVA, id: diva2:1291154
Available from: 2019-02-22 Created: 2019-02-22 Last updated: 2019-04-25Bibliographically approved
In thesis
1. Conservation of landlocked Atlantic salmon in a regulated river: Behaviour of migratory spawners and juveniles
Open this publication in new window or tab >>Conservation of landlocked Atlantic salmon in a regulated river: Behaviour of migratory spawners and juveniles
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Hydropower dams represent one of the major threats to river ecosystems today. The dams block migratory routes in many rivers, which is problematic for migratory fish species. Trap-and-transport may be an alternative to fish passage solutions, as a strategy to compensate for lost river connectivity. Stocking of hatchery fish is another mitigating measure often used to compensate for reduced yields in fisheries, but also as supportive breeders in declining populations.

 

In this thesis, I report the results from radio-telemetry studies where the behavior of migrating Atlantic salmon spawners has been investigated in a regulated river. I also studied the function and success of using hatchery fish as supportive breeders and if there are any effects of migratory timing on migratory success. Further, I evaluated upstream passage performance by Atlantic salmon and brown trout at fishways in rivers Klarälven, Sweden and Gudbrandslågen, Norway. The goal was to determine if prior fishway experience had an effect on passage success. I identified three problems associated with the current river management, namely the high incidence of fallbacks among the early migrating salmon, the negative effects of high river flow and prior experience on fishway efficacy and that the use of hatchery-reared fish as supportive breeders have little, if any, positive effect on reproduction. Finally, I examined the competitive interactions that may occur when reintroducing Atlantic salmon to areas with native grayling and brown trout. I found no evidence of Atlantic salmon affecting grayling or brown trout. Instead, Atlantic salmon were dominated by the other two species, which indicates that reintroduction of salmon may not be successful, especially if habitat diversity is constrained.

 

Conservation and management of migratory salmonids requires an understanding of their ecology and life-histories. In the regulated river Klarälven, populations of landlocked Atlantic salmon and migratory brown trout have declined due to river exploitation. The results presented in this thesis originate from concerns regarding salmonid conservation in regulated rivers, with a focus on the difficulties migratory spawners may face in these altered environments.

Abstract [en]

In this thesis, I report the results from radio-telemetry studies where the behavior and success of migrating Atlantic salmon (Salmo salar) spawners has been investigated in a regulated river. I have also studied the function of using hatchery fish as supportive breeders and evaluated the upstream passage performance by Atlantic salmon and brown trout (Salmo trutta) at fishways in the River Klarälven, Sweden and Gudbrandslågen, Norway.

I identified three problems associated with management in a regulated river, namely the high incidence of fallbacks among the early migrating salmon, the negative effects of high river flow and prior experience on fishway efficacy and that the use of hatchery-reared fish as supportive breeders have little, if any, positive effect on reproduction.

Finally, I examined the competitive interactions that may occur when reintroducing Atlantic salmon to areas with native grayling (Thymallus thymallus) and brown trout.

Conservation and management of migratory salmonids requires an understanding of ecology and life-histories. The results presented in this thesis originate from concerns regarding salmonid conservation in regulated rivers, with a focus on the difficulties migratory spawners may face in these altered environments. The results of my research can be applied to other regulated systems, particularly those with trap and transport solutions.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2019. p. 51
Series
Karlstad University Studies, ISSN 1403-8099 ; 2019:7
Keywords
Atlantic salmon, conservation, migration, spawning, hydropower, competition, juveniles, brown trout, hatchery reared, fallback, delay
National Category
Biological Sciences
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-71333 (URN)978-91-7867-002-4 (ISBN)978-91-7867-007-9 (ISBN)
Public defence
2019-04-12, Sjöströmssalen 1B309, Karlstad Universitet, Karlstad, 10:15 (English)
Opponent
Supervisors
Available from: 2019-03-22 Created: 2019-02-22 Last updated: 2019-05-08Bibliographically approved

Open Access in DiVA

No full text in DiVA

Authority records BETA

Hagelin, AnnaGreenberg, LarryCalles, OlleBergman, Eva

Search in DiVA

By author/editor
Hagelin, AnnaGreenberg, LarryCalles, OlleBergman, Eva
By organisation
Department of Environmental and Life Sciences (from 2013)
Biological Sciences

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 21 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf