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Publications (10 of 165) Show all publications
Motyka, R., Calles, O., Lind, L. & Watz, J. (2023). Growth and behaviour of juvenile European eel (Anguilla anguilla) in sandy and stony bottom substrates. Ecology of Freshwater Fish, 32(3), 640-647
Open this publication in new window or tab >>Growth and behaviour of juvenile European eel (Anguilla anguilla) in sandy and stony bottom substrates
2023 (English)In: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633, Vol. 32, no 3, p. 640-647Article in journal (Refereed) Published
Abstract [en]

Understanding how the physical habitat influences growth and behaviour is essential for developing effective habitat restoration programmes of threatened and endangered fish species. In our study, we compared the growth and behaviour of juvenile European eel during 13 weeks in aquaria with either sand (0.8-2 mm) or pebbles (25-40 mm) as bottom substrate. In aquaria with the pebble substrate, eel grew significantly faster than in aquaria with sand (specific growth rate 0.15 vs. 0.11% day(-1)). Moreover, growth rates varied more for individuals inhabiting aquaria with sand than in those with pebbles (coefficient of variation 1.26 vs. 0.67). Habitat-dependent growth rates may partly be explained by the observed differences in behavioural patterns. In aquaria with sand, eel left the substrate more often and moved close to the bottom or freely in water column. In aquaria with pebbles, eel remained hidden in the substrate to a high degree, also during feeding. These results may be important for prioritising connectivity- and habitat-restoring measures and for optimization of restocking programmes.

Place, publisher, year, edition, pages
John Wiley & Sons, 2023
Keywords
conservation, elver, foraging, habitat, SGR
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-94372 (URN)10.1111/eff.12716 (DOI)000958628400001 ()2-s2.0-85151976844 (Scopus ID)
Funder
Karlstad University
Available from: 2023-04-20 Created: 2023-04-20 Last updated: 2023-12-11Bibliographically approved
Kjærås, H., Baktoft, H., Silva, A. T., Gjelland, K. Ø., Økland, F., Forseth, T., . . . Calles, O. (2023). Three-dimensional migratory behaviour of European silver eels (Anguilla anguilla) approaching a hydropower plant. Journal of Fish Biology, 102(2), 465-478
Open this publication in new window or tab >>Three-dimensional migratory behaviour of European silver eels (Anguilla anguilla) approaching a hydropower plant
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2023 (English)In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 102, no 2, p. 465-478Article in journal (Refereed) Published
Abstract [en]

The global population of European eel (Anguilla anguilla) is rapidly declining, and migration barriers in rivers are believed to be one of several key causes. While progress has been made in the development of bypass solutions, they are often constructed based on a limited knowledge of swimming behaviour. A bypass close to the stream bed is often recommended at fish passage facilities to accommodate downstream eel migration. The results of this recommendation are poorly studied, and the few studies that exist show varying bypass efficiencies. The current study used acoustic telemetry with depth sensors to explore the three-dimensional migratory behaviour of downstream-migrating silver eels. The eels were tracked as they approached a hydropower plant with a state-of-the-art angled bar rack and full-depth bypass. Downstream and upstream swimming differed in preferred vertical and lateral positions. During periods of local downstream movement, the density of observations was largest in the upper middle section, away from the river boundaries and in higher velocities. Conversely, when moving upstream, eels tended to avoid the upper layers of the middle part of the river, swimming closer to the riverbed and using the bank areas to a greater extent. Downstream-moving fish swam higher in the water column during night and in turbid conditions (high discharge). When approaching the impassable bar rack and the full-depth bypass, the eels searched most intensely but not exclusively along the bottom third of the rack, often exploring at new depths after changing direction. The impediment passage efficiency was 100% when both bypass solutions were considered. The study provides knowledge of the swimming behaviour of silver eels, which is relevant for the design of bypass solutions for eels at migration barriers. 

Place, publisher, year, edition, pages
John Wiley & Sons, 2023
Keywords
acoustic telemetry, Anguilla anguilla, bypass solutions, downstream, migration, swimming depth
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-92827 (URN)10.1111/jfb.15278 (DOI)000895888600001 ()36433764 (PubMedID)2-s2.0-85144133119 (Scopus ID)
Funder
The Research Council of Norway, 244022, 257588
Available from: 2023-01-02 Created: 2023-01-02 Last updated: 2023-04-13Bibliographically approved
Watz, J., Aldvén, D., Andreasson, P., Aziz, K., Blixt, M., Calles, O., . . . Piccolo, J. (2022). Atlantic salmon in regulated rivers: Understanding river management through the ecosystem services lens. Fish and Fisheries, 23(2), 478-491
Open this publication in new window or tab >>Atlantic salmon in regulated rivers: Understanding river management through the ecosystem services lens
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2022 (English)In: Fish and Fisheries, ISSN 1467-2960, E-ISSN 1467-2979, Vol. 23, no 2, p. 478-491Article in journal (Refereed) Published
Abstract [en]

Known as the “king of fishes”, the Atlantic salmon (Salmo salar, Salmonidae) is an iconic freshwater species whose contribution to human wellbeing has long been recognized, as have widespread declines in its abundance, partly due to river regulation. To understand how salmon conservation has been addressed within the ecosystem services (ES) framework, we synthesized the peer-reviewed literature on ES provided by salmon in regulated rivers. We developed a search string to capture allusions to provisioning, regulating, supporting and cultural ES and assessed the results to identify knowledge gaps. The effects of hydropower on fisheries catches and on modelled populations were shown is several publications. Overall, few studies focused explicitly on ES from salmon and hydropower; this is surprising given the considerable body of literature on salmon in regulated rivers. Wild salmon as a food source and other provisioning services are less important today than historically. Because predators such as salmon are important for facilitating biodiversity by cycling nutrients and controlling food webs, there is a scope of work for future assessments of these regulating and supporting services. Few papers explicitly addressed cultural ES, despite the salmon’s longstanding iconic status; this is a knowledge gap for future ES assessments in relation to hydropower. The influence of ES assessments for policy makers is growing through the Intergovernmental Panel for Biodiversity and Ecosystem Services (IPBES) and the post-2020 biodiversity strategy. Explicitly addressing ES poses an opportunity for river managers to raise awareness of aquatic conservation efforts and well-informed decision-making for sustaining ES.

Place, publisher, year, edition, pages
John Wiley & Sons, 2022
Keywords
Management, Monitoring, Policy and Law, Aquatic Science, Ecology, Evolution, Behavior and Systematics, Oceanography
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-87195 (URN)10.1111/faf.12628 (DOI)000716334500001 ()2-s2.0-85118708794 (Scopus ID)
Funder
European Commission, LIFE18 NAT/SE/000742Knowledge Foundation, 20170129
Available from: 2021-11-16 Created: 2021-11-16 Last updated: 2022-10-31Bibliographically approved
Harbicht, A., Watz, J., Nyqvist, D., Virmaja, T., Carlsson, N., Aldven, D., . . . Calles, O. (2022). Guiding migrating salmonid smolts: Experimentally assessing the performance of angled and inclined screens with varying gap widths. Ecological Engineering: The Journal of Ecotechnology, 174, 1-8, Article ID 106438.
Open this publication in new window or tab >>Guiding migrating salmonid smolts: Experimentally assessing the performance of angled and inclined screens with varying gap widths
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2022 (English)In: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 174, p. 1-8, article id 106438Article in journal (Refereed) Published
Abstract [en]

The loss of longitudinal connectivity in regulated rivers, both up- and downstream, has been detrimental for biodiversity worldwide. While progress has been made regarding upstream fish passage solutions, many questions remain unanswered regarding downstream passage alternatives. To address these knowledge gaps, we used Atlantic salmon (S. salar) smolts to experimentally assess the guidance efficiency and passage rates produced by several common screen-and-bypass fish guidance systems. Vertical screens with horizontally oriented bars extending across a turbine intake channel at a shallow angle (angled guidance screens), combined with a single, full-depth bypass entrance at their downstream end, were on average 20% more effective and produced passage rates that were 10 times higher than screens which extended perpendicularly across a turbine intake channel with vertically oriented bars that rose gradually towards the surface (inclined guidance screens) and with a bypass at the surface, on either side of the screen. Among inclined screens, gap width was negatively associated with guidance efficiencies and the smallest gap width (15 mm) exhibited a 41% greater guidance efficiency than the largest (30 mm). Among angled screens, performance was more closely linked to construction material as metal racks produced passage rates over three times faster than flexible Kevlar netting. Overall, passage through the guidance screens, and therefore into a tentative turbine intake area, was positively associated with gap width and was twice as prevalent among the inclined relative to angled guidance screens. Ultimately, an angled guidance screen with a 30 mm gap width produced the highest guidance efficiency and passage rates (a 30% improvement over the next best screen), while an inclined screen with a 30 mm gap width produced the lowest guidance efficiencies and passage rates. These results have implications for the suitability and performance of downstream fish passage solutions at both large- and small-scale hydropower plants where passage solutions are currently lacking or inadequate.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Angled rack, Inclined rack, Fish guidance, Fish passage, Bypass, Downstream migration, S, salar
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-87281 (URN)10.1016/j.ecoleng.2021.106438 (DOI)000704477900003 ()2-s2.0-85116023628 (Scopus ID)
Available from: 2021-11-22 Created: 2021-11-22 Last updated: 2022-01-24Bibliographically approved
Watz, J., Hajiesmaeili, M., Addo, L., Calles, O., Nordblom, O., Tielman, J. & Piccolo, J. (2022). Hur mycket vatten behöver havsöringen? En jämförelse av en korrelativ och en individbaserad modell för att förutsäga effekter av flöden på strömlevande fiskar: How much water do sea trout need? A comparison between a correlative and an individual-based model to predict effects of flow on stream fish populations. Vatten, 78(2), 107-114
Open this publication in new window or tab >>Hur mycket vatten behöver havsöringen? En jämförelse av en korrelativ och en individbaserad modell för att förutsäga effekter av flöden på strömlevande fiskar: How much water do sea trout need? A comparison between a correlative and an individual-based model to predict effects of flow on stream fish populations
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2022 (Swedish)In: Vatten, ISSN 0042-2886, Vol. 78, no 2, p. 107-114Article in journal (Other academic) Published
Abstract [sv]

Modeller för att simulera effekter av flöde på strömlevande fiskpopulationer är kraftfulla verktyg för att avväga miljönytta och kostnad i samband med åtgärder för att minimera vattenkraftens miljöpåverkan. Vi jämförde en korrelativ och en individbaserad fiskhabitatmodell med avseende på vilka flöden respektive modell bedömde var gynnsammast för en potentiell havsöringspopulation i naturfåran vid Blankaströms kraftverk i Emån. Den korrelativa modellen förutspådde att ett optimalt flöde för att maximera arean med högkvalitativt öringhabitat låg mellan 2 och 3 m3/s. Den individbaserade modellen fann att flöde spelade mindre roll för överlevnad hos den yngsta årsklassen (0+), samt att tillväxten hos dessa var som högst vid 3 m3/s. Högre flöden krävdes dock för lyckad reproduktion och att överlevnaden och tillväxten hos äldre juveniler (1+) gynnades av flöden mellan 5 och 8 m3/s. Korrelativa modeller kan vara användbara, då de är enkla att använda, men det är möjligt att de framförallt förutsäger habitatförekomst för 0+-öringar och sämre speglar de miljöförhållanden som krävs för 1+-öringars uppväxt samt lekfiskars reproduktionsframgång. Individbaserade modeller, å andra sidan, är något mer komplicerade, men genererar mångfacetterad data för olika livsstadier, ger mekanistiska förklaringar till observerade fenomen och kan anpassas till dynamiska flöden.

Place, publisher, year, edition, pages
Lund: Föreningen Vatten, 2022
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-91786 (URN)
Funder
Knowledge Foundation, 20170129
Available from: 2022-09-05 Created: 2022-09-05 Last updated: 2022-10-07Bibliographically approved
Nyqvist, D., Calles, O., Forneris, G. & Comoglio, C. (2022). Movement and Activity Patterns of Non-Native Wels Catfish (Silurus glanis Linnaeus, 1758) at the Confluence of a Large River and Its Colder Tributary. Fishes, 7(6), Article ID 325.
Open this publication in new window or tab >>Movement and Activity Patterns of Non-Native Wels Catfish (Silurus glanis Linnaeus, 1758) at the Confluence of a Large River and Its Colder Tributary
2022 (English)In: Fishes, E-ISSN 2410-3888, Vol. 7, no 6, article id 325Article in journal (Refereed) Published
Abstract [en]

The establishment and proliferation of non-native fish species can have a range of effects within the local ecosystem, including alteration of food webs, nutrient cycling, pathogen dynamics and predation, sometimes also resulting in changed behavior and distribution of native fish species. Knowledge about movements and activity patterns is important to understand the dynamics of non-native animals in their new environment. The Wels catfish (Silurus glanis Linnaeus, 1758) is considered an invasive species in many places in Western Europe, and regional control programs are in place. Here, using radiotelemetry, we study the movements and activity patterns of invasive Wels catfish at an invasion front within the Po River (Italy); namely, at the confluence between the main river, where the species is abundant, and a colder tributary, the Dora Baltea River, where it is absent. In addition, we also investigate potential spatiotemporal overlap between Wels catfish and native and endangered marble trout (Salmo marmoratus Cuvier, 1829) in the area. A total of nine Wels catfish and eight marble trout were tagged. The Wels catfish showed a very high degree of residency within the study area in the Po River, close to the mouth the colder tributary. Despite this, only one catfish entered the lower reaches of the tributary and did so only occasionally during August. No catfish moved further upstream in the tributary. It is likely that lower temperatures in combination with more challenging hydrodynamic conditions made the tributary unattractive to the catfish. The catfish were active during all times of the day but substantially more so during evenings and at nights. Some, but not all, tagged catfish moved to areas in the main stem upstream of the confluence with the tributary. A large proportion of the tagged marble trout made occasional or longer visits to the Po River, with several individuals becoming resident, but without apparent mortality, in the tagged catfish home range. The high residency of the Wels catfish suggests that removal efforts may do well to initially focus on areas close to the habitats of species under conservation concern.

Place, publisher, year, edition, pages
MDPI, 2022
Keywords
invasive species, Wels catfish, marble trout, invasion front, radio telemetry, daily activity, temperature
National Category
Ecology Fish and Aquacultural Science
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-92892 (URN)10.3390/fishes7060325 (DOI)000901052300001 ()2-s2.0-85144677598 (Scopus ID)
Available from: 2023-01-09 Created: 2023-01-09 Last updated: 2023-01-23Bibliographically approved
Calles, O., Elghagen, J., Nyqvist, D., Harbicht, A. & Nilsson, P. A. (2021). Efficient and timely downstream passage solutions for European silver eels at hydropower dams. Ecological Engineering: The Journal of Ecotechnology, 170, Article ID 106350.
Open this publication in new window or tab >>Efficient and timely downstream passage solutions for European silver eels at hydropower dams
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2021 (English)In: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 170, article id 106350Article in journal (Refereed) Published
Abstract [en]

The European eel population is critically endangered due to a multitude of human-induced factors such as habitat fragmentation, parasites, fishing, and climate change. In freshwater, downstream migrating silver eels encountering hydroelectric plants often suffer substantial delays and increased mortality from trash-rack impingement and turbine-induced mortality. Downstream passage problems can be ameliorated by implementing different types of downstream passage solutions that show variable but promising results for salmonids, but their performance for silver eels remains largely unknown. To address these knowledge gaps, radio telemetry was used to monitor the downstream migration of silver eels during 2 years past a hydroelectric plant recently equipped with two new fish passage solutions, consisting of an angled bar rack with a full-depth bypass, and a nature-like fishway. No tagged eels passed through the turbines, but bypassed the dam evenly between the two passage solutions, resulting in a 95% impediment passage efficiency and a median passage time of 1 h. Movement patterns and route selection were associated with variation in discharge and most individuals approached both passage solutions before passing, resulting in route-specific efficiencies of 69% for the angled rack and bypass, and 46% for the nature-like fishway. We conclude that the combination of a new bypass, paired with an angled rack, and a large nature-like fishway provided downstream migrating silver eels with a highly effective combination of passage solutions, with high impediment passage success and relatively low passage times.

Place, publisher, year, edition, pages
Elsevier, 2021
Keywords
Angled rack, Nature-like fishway, Migration barriers, Passage time, Passage efficiency, Anguilla anguilla, Fish migration
National Category
Ecology
Research subject
Environmental Science
Identifiers
urn:nbn:se:kau:diva-85856 (URN)10.1016/j.ecoleng.2021.106350 (DOI)000687624200007 ()2-s2.0-85110508889 (Scopus ID)
Available from: 2021-09-07 Created: 2021-09-07 Last updated: 2022-05-23Bibliographically approved
Harbicht, A., Nilsson, P. A., Österling, M. & Calles, O. (2021). Environmental and anthropogenic correlates of migratory speeds among Atlantic salmon smolts. Rivers Research and Applications: an international journal devoted to river research and management, 37(3), 358-372
Open this publication in new window or tab >>Environmental and anthropogenic correlates of migratory speeds among Atlantic salmon smolts
2021 (English)In: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467, Vol. 37, no 3, p. 358-372Article in journal (Refereed) Published
Abstract [en]

Dams, weirs, and hydropower facilities are often cited as migratory barriers which impart significant reductions in fitness among migratory fish species. Even where upstream and downstream passage options are available, barrier passage can still often result in energetic or physical costs which compound delays or cause mortality. Past studies have identified variables associated with such fitness reductions, though few examine their effects in the context of the whole river scale. To this end, we assessed the migratory rates and downstream passage of radio-tagged Atlantic salmon (Salmo salar) smolts through nine river sections (including two reservoir sections and one dammed section) along a 20 km stretch of river. Migration stoppages were not found to be elevated in reservoir or dammed sections, while migration rates were best described by physical river properties (width), biological traits (smolt total length), and seasonal variables (diel period) rather than anthropogenic factors. These results suggest the negative effect of reservoirs may primarily be due to their influence on river width and may be negligible when width is largely unaffected by an impoundment. Similarly, spilling water during fish migrations as a mitigative measure appears to make delays negligible. These conditions and actions may not completely marginalize the effect of dams, however, as a negative trend was still observed resulting from passage effects at the dam.

Keywords
anthropogenic delay, migration barriers, Salmo salar, smolt, time&#8208, to&#8208, event analysis
National Category
Biological Sciences
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-82500 (URN)10.1002/rra.3760 (DOI)000601923900001 ()2-s2.0-85098069592 (Scopus ID)
Available from: 2021-01-21 Created: 2021-01-21 Last updated: 2022-05-11Bibliographically approved
Lund Bjørnås, K., Railsback, S. F., Calles, O. & Piccolo, J. (2021). Modeling Atlantic salmon (Salmo salar) and brown trout (S. trutta) population responses and interactions under increased minimum flow in a regulated river. Ecological Engineering: The Journal of Ecotechnology, 162, Article ID 106182.
Open this publication in new window or tab >>Modeling Atlantic salmon (Salmo salar) and brown trout (S. trutta) population responses and interactions under increased minimum flow in a regulated river
2021 (English)In: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 162, article id 106182Article in journal (Refereed) Published
Abstract [en]

Describing and understanding the relationship between streamflow and ecological processes is a classic problem in stream ecology and river management. We applied the individual-based model inSTREAM to describe the relationship between the dynamic river habitat and emergent population responses in sympatric landlocked Atlantic salmon (Salmo salar) and lake-migrating brown trout (Salmo trutta). This application explicitly describes the environmental conditions in the Gullspang Rapids, a residual flow stretch in the hydropower-regulated Gullspang River, Sweden (Svenskt elfiskeregister - SERS, 2019) etween September 2008 and September 2018. We simulated three static minimum flow scenarios and three variable natural flow regimes, contrasting highly artificial conditions with more natural dynamics. Our main response variable was the number of large (>= 12 cm) out-migrants of salmon and trout, a proxy for successful population recruitment. The baseline model predicted an average production of 455 salmon and 532 trout out-migrants per year during 2008-2018 in this 11,700 m(2) spawning and rearing area. The only alternative scenario producing more out-migrants was when the minimum flow was raised by a factor of three, as this led to a modest increase in trout out-migrants. Interestingly, none of the flow alternatives produced more salmon out-migrants than the baseline model, suggesting a competitive disadvantage originating from spawning later than trout. Density-dependent population regulation, a well-known phenomenon in salmonids, was reproduced by the model. Both intra- and interspecific competition was evident. While the number of out-migrants varied with flow regime, sensitivity analyses showed that other model input, specifically velocity shelter availability and stream temperature, were just as important. Increased availability of velocity shelters (in-stream structures that reduces the swimming speed of drift-feeding fish) was the only environmental factor that increased production of both salmon and trout in silico. We conclude that in this system, flow restoration based on simplistic flow scenarios will have limited effect, unless complemented by an increase of instream structural complexity.

Place, publisher, year, edition, pages
Elsevier, 2021
Keywords
Ecohydraulic; Hydropower; Individual-based modeling; Environmental flow; Natural flow regime; River restoration
National Category
Biological Sciences
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-76558 (URN)10.1016/j.ecoleng.2021.106182 (DOI)000632443700007 ()2-s2.0-85101647286 (Scopus ID)
Funder
Knowledge Foundation, 20170129
Note

Additional funder: Fortum AB

The article was published as manuscript in Lund Bjørnås licentiate thesis (2020): Modeling Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) responses to river habitat alteration

Available from: 2020-01-28 Created: 2020-01-28 Last updated: 2022-05-11Bibliographically approved
Hagelin, A., Museth, J., Greenberg, L., Kraabol, M., Calles, O. & Bergman, E. (2021). Upstream fishway performance by Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) spawners at complex hydropower dams – is prior experience a success criterion?. Canadian Journal of Fisheries and Aquatic Sciences, 78(2), 124-134
Open this publication in new window or tab >>Upstream fishway performance by Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) spawners at complex hydropower dams – is prior experience a success criterion?
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2021 (English)In: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533, Vol. 78, no 2, p. 124-134Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
CANADIAN SCIENCE PUBLISHING, 2021
Keywords
Atlantic salmon, brown trout, migration, spawners, spawning, fishways, fish passage solutions, delay, hydropower
National Category
Biological Sciences
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-71325 (URN)10.1139/cjfas-2019-0271 (DOI)000618063000003 ()2-s2.0-85100598161 (Scopus ID)
Funder
European Regional Development Fund (ERDF)The Research Council of Norway, 221454 244022European Commission
Note

Artikeln med som manuskript i Hagelins (2019) doktorsavhandling: Conservation of landlocked Atlantic salmon in a regulated river: Behaviour of migratory spawners and juveniles.

Available from: 2019-02-22 Created: 2019-02-22 Last updated: 2021-04-19Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-8738-8815

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