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Gordon, T. A., Harding, H. R., Clever, F. K., Davidson, I. K., Davison, W., Montgomery, D. W., . . . Santos, E. M. (2018). Fishes in a changing world: learning from the past to promote sustainability of fish populations. Paper presented at 50th Anniversary Annual Symposium of the Fisheries-Society-of-the-British-Isles (FSBI) - Understanding Fish Populations, JUL 03-07, 2017, Univ Exeter, Exeter, ENGLAND. Journal of Fish Biology, 92(3), 804-827
Open this publication in new window or tab >>Fishes in a changing world: learning from the past to promote sustainability of fish populations
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2018 (English)In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 92, no 3, p. 804-827Article in journal (Refereed) Published
Abstract [en]

Populations of fishes provide valuable services for billions of people, but face diverse and interacting threats that jeopardize their sustainability. Human population growth and intensifying resource use for food, water, energy and goods are compromising fish populations through a variety of mechanisms, including overfishing, habitat degradation and declines in water quality. The important challenges raised by these issues have been recognized and have led to considerable advances over past decades in managing and mitigating threats to fishes worldwide. In this review, we identify the major threats faced by fish populations alongside recent advances that are helping to address these issues. There are very significant efforts worldwide directed towards ensuring a sustainable future for the world's fishes and fisheries and those who rely on them. Although considerable challenges remain, by drawing attention to successful mitigation of threats to fish and fisheries we hope to provide the encouragement and direction that will allow these challenges to be overcome in the future.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Biological Sciences Other Social Sciences
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-66874 (URN)10.1111/jfb.13546 (DOI)000427477600016 ()29537086 (PubMedID)
Conference
50th Anniversary Annual Symposium of the Fisheries-Society-of-the-British-Isles (FSBI) - Understanding Fish Populations, JUL 03-07, 2017, Univ Exeter, Exeter, ENGLAND
Available from: 2018-03-29 Created: 2018-03-29 Last updated: 2018-04-04Bibliographically approved
Nyqvist, D., McCormick, S. D., Greenberg, L., Ardren, W. R., Bergman, E., Calles, O. & Castro-Santos, T. (2017). Downstream migration and multiple dam passage by Atlantic salmon smolts. North American Journal of Fisheries Management, 4(37), 816-828
Open this publication in new window or tab >>Downstream migration and multiple dam passage by Atlantic salmon smolts
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2017 (English)In: North American Journal of Fisheries Management, ISSN 0275-5947, E-ISSN 1548-8675, Vol. 4, no 37, p. 816-828Article in journal (Refereed) Published
Abstract [en]

The purpose of this study was to investigate behavior and survival of radio-tagged wild and hatchery-reared landlocked Atlantic Salmon Salmo salar smolts as they migrated past three hydropower dams equipped with fish bypass solutions in the Winooski River, Vermont. Among hatchery-reared smolts, those released early were more likely to initiate migration and did so after less delay than those released late. Once migration was initiated, however, the late-released hatchery smolts migrated at greater speeds. Throughout the river system, hatchery-reared fish performed similarly to wild fish. Dam passage rates varied between the three dams and was highest at the dam where unusually high spill levels occurred throughout the study period. Of the 50 fish that did migrate downstream, only 10% managed to reach the lake. Migration success was low despite the presence of bypass solutions, underscoring the need for evaluations of remedial measures; simply constructing a fishway is not synonymous with providing fish passage.

Place, publisher, year, edition, pages
Taylor & Francis, 2017
Keywords
SALAR SMOLTS; CHINOOK SALMON; FISH PASSAGE; JUVENILE SALMONIDS; DELAYED MORTALITY; COLUMBIA RIVER; SNAKE RIVER; HYDROPOWER SYSTEM; TRUTTA SMOLTS; K+ ATPASE
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-46900 (URN)10.1080/02755947.2017.1327900 (DOI)000407192600012 ()
Available from: 2016-10-19 Created: 2016-10-19 Last updated: 2018-09-10Bibliographically approved
Nyqvist, D., Bergman, E., Calles, O. & Greenberg, L. (2017). Intake Approach and Dam Passage by Downstream-migrating Atlantic Salmon Kelts. Rivers Research and Applications: an international journal devoted to river research and management, 33(5), 697-706
Open this publication in new window or tab >>Intake Approach and Dam Passage by Downstream-migrating Atlantic Salmon Kelts
2017 (English)In: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467, Vol. 33, no 5, p. 697-706Article in journal (Refereed) Published
Abstract [en]

Studying fish behaviour at hydropower dams is needed to facilitate the design and improvement of fish passage solutions, but few studies have focused on Atlantic salmon kelts. Here, we used radio telemetry (n = 40, size range = 50–81 cm) and acoustic sonar to study kelt movements in the forebay as well as their dam passage survival and subsequent migration success past multiple dams. We also compare radio telemetry and acoustic sonar observations of fish behaviour and used acoustic sonar to measure the depth distribution of fish approaching the turbine intake zone. Passage success at the dam was 41%, and mortality was largely associated with turbine passage (62%). The two fish that passed via the spill gates survived and continued their downstream migration. At the dam, all but one radio-tagged kelt approached the intake zone shortly after arrival to the forebay, and sonar data showed that approaching fish were predominantly surface oriented (72%, 88% and 96% of the observations were less than 1, 2 and 3 m deep, respectively). Turbine passage rate from the intake zone was higher at night than at day, indicating that the lack of visual cues may reduce the barrier effect of the 70-mm conventional trash rack. Turbine passage rate also increased with increasing hydropower generation. The percentage of observed upstream movements away from the intake zone compared with the total number of observations was considerably greater in the radio telemetry data (41%) than in the sonar data (4%). Only one fish survived passage of all eight hydropower dams to reach the lake. This low-passage survival underscores the need for remedial measures to increase the survival of migrating kelts, and the fish's surface orientation as well as their rapid approach to the intake rack should be taken into account when designing such measures.

Place, publisher, year, edition, pages
John Wiley & Sons, 2017
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-46902 (URN)10.1002/rra.3133 (DOI)000402840900006 ()
Note

Was published as manuscript in D. Nyquists thesis and had then the title "Intake approach and dam passage by landlocked Atlantic salmon kelts at a hydropower dam"

Available from: 2016-10-19 Created: 2016-10-19 Last updated: 2018-09-10Bibliographically approved
Nyqvist, D., Greenberg, L., Calles, O., Goerig, E., Bergman, E., Ardren, W. & Castro-Santos, T. (2017). Migratory delay leads to reduced passage success of Atlantic salmon smolts at a hydroelectric dam. Ecology of Freshwater Fish, 26(4), 707-718
Open this publication in new window or tab >>Migratory delay leads to reduced passage success of Atlantic salmon smolts at a hydroelectric dam
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2017 (English)In: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633, Vol. 26, no 4, p. 707-718Article in journal (Refereed) Published
Abstract [en]

Passage of fish through hydropower dams is associated with mortality, delay, increased energy expenditure and migratory failure for migrating fish and the need for remedial measures for both upstream and downstream migration is widely recognised. A functional fish passage must ensure safe and timely passage routes that a substantial portion of migrating fish will use. Passage solutions must address not only the number or percentage of fish that successfully pass a barrier, but also the time it takes to pass. Here, we used radiotelemetry to study the functionality of a fish bypass for downstream-migrating wild-caught and hatchery-released Atlantic salmon smolts. We used time-to-event analysis to model the influence of fish characteristics and environmental variables on the rates of a series of events associated with dam passage. Among the modelled events were approach rate to the bypass entry zone, retention rates in both the forebay and the entry zone and passage rates. Despite repeated attempts, only 65% of the tagged fish present in the forebay passed the dam. Fish passed via the bypass (33%), via spill (18%) and via turbines (15%). Discharge was positively related to approach, passage and retention rates. We did not detect any differences between wild and hatchery fish. Even though individual fish visited the forebay and the entry zone on multiple occasions, most fish passed during the first exposures to these zones. This study underscores the importance of timeliness to passage success and the usefulness of time-to-event analysis for understanding factors governing passage performance.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2017
Keywords
downstream passage, fish passage, landlocked salmon, Salmo salar, smolt migration, nedströmspassage, fiskpassage, smolt, lax
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-46897 (URN)10.1111/eff.12318 (DOI)000409505000019 ()
Available from: 2016-10-19 Created: 2016-10-19 Last updated: 2018-09-10Bibliographically approved
Enefalk, Å. & Bergman, E. (2016). Effect of fine wood on juvenile brown trout behaviour in experimental stream channels. Ecology of Freshwater Fish, 25(4), 664-673
Open this publication in new window or tab >>Effect of fine wood on juvenile brown trout behaviour in experimental stream channels
2016 (English)In: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633, Vol. 25, no 4, p. 664-673Article in journal (Refereed) Published
Abstract [en]

In-stream wood can increase shelter availability and prey abundance for stream-living fish such as brown trout, Salmo trutta, but the input of wood to streams has decreased in recent years due to harvesting of riparian vegetation. During the last decades, fine wood (FW) has been increasingly used for biofuel, and the input of FW to streams may therefore decrease. Although effects of in-stream FW have not been studied as extensively as those of large wood (LW), it is probably important as shelter for small-sized trout. In a laboratory stream experiment, we tested the behavioural response of young-of-the-year wild brown trout to three densities of FW, with trout tested alone and in groups of four. Video recordings were used to measure the proportion of time allocated to sheltering, cruising and foraging, as well as the number of aggressive interactions and prey attacks. Cruising activity increased with decreasing FW density and was higher in the four-fish groups than when fish were alone. Foraging decreased and time spent sheltering in FW increased with increasing FW density. Our study shows that juvenile trout activity is higher in higher fish densities and that trout response to FW is related to FW density and differs from the response to LW as reported by others. © 2015 John Wiley & Sons A/S.

Place, publisher, year, edition, pages
John Wiley & Sons, 2016
Keywords
salmonid; YOY; streams; wood; small woody debris
National Category
Ecology Biological Sciences
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-42488 (URN)10.1111/eff.12244 (DOI)000388307300015 ()2-s2.0-84938718603 (Scopus ID)
Available from: 2016-05-27 Created: 2016-05-23 Last updated: 2017-12-06Bibliographically approved
Enefalk, Å. & Bergman, E. (2016). Effects of fine wood on macroinvertebrate drift in four boreal forest streams. Hydrobiologia, 765(1), 317-327
Open this publication in new window or tab >>Effects of fine wood on macroinvertebrate drift in four boreal forest streams
2016 (English)In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 765, no 1, p. 317-327Article in journal (Refereed) Published
Abstract [en]

Most studies of stream wood have focused on pieces a parts per thousand yen0.1 m diameter. However, this approach may overlook an important feature of small streams, where wood < 0.1 m can constitute the majority of wood pieces. We examined the effect of fine wood (FW) on local drift of stream macroinvertebrates. The study was carried out at seven sites in four boreal forest streams, from early June to mid-August 2011. This was done by anchoring bundles of FW at each site and measuring drift upstream and downstream of each bundle. We hypothesized that FW would increase drift density, biomass and diversity of aquatic invertebrates. Ten weeks after FW addition, aquatic drift density was higher downstream than upstream of FW bundles, while drift biomass and drift diversity did not differ significantly downstream and upstream of FW.

Keywords
Invertebrates, Colonization, FWD, In-stream wood, Small woody debris
National Category
Biological Sciences
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-40971 (URN)10.1007/s10750-015-2423-x (DOI)000366641200022 ()
Available from: 2016-03-03 Created: 2016-03-03 Last updated: 2017-12-06Bibliographically approved
Watz, J., Bergman, E., Piccolo, J. & Greenberg, L. (2016). Ice cover affects the growth of a stream-dwelling fish. Oecologia, 181(1), 299-311
Open this publication in new window or tab >>Ice cover affects the growth of a stream-dwelling fish
2016 (English)In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 181, no 1, p. 299-311Article in journal (Refereed) Published
Abstract [en]

Protection provided by shelter is important for survival and affects the time and energy budgets of animals. It has been suggested that in fresh waters at high latitudes and altitudes, surface ice during winter functions as overhead cover for fish, reducing the predation risk from terrestrial piscivores. We simulated ice cover by suspending plastic sheeting over five 30-m-long stream sections in a boreal forest stream and examined its effects on the growth and habitat use of brown trout (Salmo trutta) during winter. Trout that spent the winter under the artificial ice cover grew more than those in the control (uncovered) sections. Moreover, tracking of trout tagged with passive integrated transponders showed that in the absence of the artificial ice cover, habitat use during the day was restricted to the stream edges, often under undercut banks, whereas under the simulated ice cover condition, trout used the entire width of the stream. These results indicate that the presence of surface ice cover may improve the energetic status and broaden habitat use of stream fish during winter. It is therefore likely that reductions in the duration and extent of ice cover due to climate change will alter time and energy budgets, with potentially negative effects on fish production.

Place, publisher, year, edition, pages
Berlin Heidelberg: Springer Berlin/Heidelberg, 2016
Keywords
Climate change, Energy budget, Global warming, Salmonid, Winter
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-39125 (URN)10.1007/s00442-016-3555-z (DOI)000374564000026 ()26787075 (PubMedID)
Available from: 2016-01-25 Created: 2016-01-25 Last updated: 2017-12-06Bibliographically approved
Nyqvist, D., Calles, O., Bergman, E., Hagelin, A. & Greenberg, L. (2016). Post-Spawning Survival and Downstream Passage of Landlocked Atlantic Salmon (Salmo salar) in a Regulated River: Is There Potential for Repeat Spawning?. Rivers Research and Applications: an international journal devoted to river research and management, 32(5), 1008-1017
Open this publication in new window or tab >>Post-Spawning Survival and Downstream Passage of Landlocked Atlantic Salmon (Salmo salar) in a Regulated River: Is There Potential for Repeat Spawning?
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2016 (English)In: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467, Vol. 32, no 5, p. 1008-1017Article in journal (Refereed) Published
Abstract [en]

Repeat salmonid spawners may make large contributions to total recruitment and long term population stability. Despite their potential importance, relatively little is known about this phase of the life history for anadromous populations, and nothing has been reported for landlocked populations. Here, we studied post-spawning behaviour and survival of landlocked Atlantic salmon in relation to downstream dam passage in the River KlarÀlven, Sweden. Eight hydropower stations separate the feeding grounds in Lake VÀnern from the spawning grounds in the River KlarÀlven, and no measures to facilitate downstream migration are present in the river. Forty-nine percent of the salmon survived spawning and initiated downstream migration. Females and small fish had higher post-spawning survival than males and large fish. The post-spawners migrated downstream in autumn and spring and remained relatively inactive in the river during winter. Downstream migration speed in the free flowing part of the river was highly variable with a median of 9.30km/day. Most fish passed the first hydropower station via upward-opening spill gates after a median residence time in the forebay of 25min. However, no tagged fish survived passage of all eight hydropower stations to reach Lake VÀnern. This result underscores the need for remedial measures to increase the survival of downstream migrating kelts.

Place, publisher, year, edition, pages
John Wiley & Sons, 2016
Keywords
migration; kelt; multiple dam passage; telemetry; hydropower; gender difference
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-42458 (URN)10.1002/rra.2926 (DOI)000378715500018 ()2-s2.0-84931843504 (Scopus ID)
Available from: 2016-05-23 Created: 2016-05-23 Last updated: 2017-11-02Bibliographically approved
Hagelin, A., Calles, O., Greenberg, L., Piccolo, J. J. & Bergman, E. (2016). Spawning migration of wild and supplementary stocked landlocked atlantic salmon (Salmo Salar). Rivers Research and Applications: an international journal devoted to river research and management, 32(3), 383-389
Open this publication in new window or tab >>Spawning migration of wild and supplementary stocked landlocked atlantic salmon (Salmo Salar)
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2016 (English)In: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467, Vol. 32, no 3, p. 383-389Article in journal (Refereed) Published
Abstract [en]

Upstream migration by adult salmonids is impeded by dams in many regulated rivers, as is the case for landlocked Atlantic salmon, Salmo salar, in the River Klarälven, Sweden. There, the salmon cannot reach the spawning grounds due to the presence of eight dams. Hence, hatchery-reared smolts are released downstream of the dams, and upstream migrating spawners are caught in a trap at the lowermost dam before transported by truck to the spawning grounds past the dams. To identify the spawning grounds and compare the behavior of wild and hatchery-reared Atlantic salmon during upstream migration and spawning, 34 wild and 28 hatchery-reared, radio-tagged Atlantic salmon were followed during their spawning migration from August to October 2011. Half (50%) of the hatchery fish, but only 11,8% of the wild fish ended up as fallbacks, i.e. they migrated past the first downstream power station, and did not spawn. A significantly higher proportion (21.4%) of hatchery- reared salmon moved in an erratic way, with several up and down stream movements, when compared to the wild salmon (5.9%). When looking at the salmon that stayed in the river (exc. fallbacks), wild individuals exhibited a holding behavior (little or no movements before presumed spawning) more often (86.7%) than the reared ones (50%). The wild salmon also held position (and presumably spawned) for longer time (25.4 days) than the reared salmon (16.1 days). Reared salmon held position, on average, 10 km further upstream than wild salmon, passing the presumed best-quality spawning habitat. The migration speed (average 17.4 km/day) between two logger stations did not differ between wild and reared fish or between sexes. Our results suggest that the reproductive success of hatchery-reared Atlantic salmon is relatively low and their capacity as supplementary spawners to the wild population in the Klarälven, is probably small.

Place, publisher, year, edition, pages
John Wiley & Sons, 2016
Keywords
Salmo salar, supplementary stocking, spawning, migratory behaviour, landlocked, telemetry
National Category
Biological Sciences
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-35930 (URN)10.1002/rra.2870 (DOI)000372354700014 ()
Available from: 2015-04-29 Created: 2015-04-29 Last updated: 2017-12-06Bibliographically approved
Hagelin, A., Calles, O., Greenberg, L., Nyqvist, D. & Bergman, E. (2016). The Migratory Behaviour and Fallback Rate of Landlocked Atlantic Salmon (Salmo salar) in a Regulated River: does Timing Matter?. Rivers Research and Applications: an international journal devoted to river research and management, 32(6), 1402-1409
Open this publication in new window or tab >>The Migratory Behaviour and Fallback Rate of Landlocked Atlantic Salmon (Salmo salar) in a Regulated River: does Timing Matter?
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2016 (English)In: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467, Vol. 32, no 6, p. 1402-1409Article in journal (Refereed) Published
Abstract [en]

The behavior of early (June-July) and late (August-September) migrating, adult Atlantic salmon, in The River Klaralven, Sweden, was analyzed using radio telemetry. River Klaralven is a regulated river without functioning fishways, instead upstream migrating salmon are trapped and trucked past eight hydropower plants before released back to the river. We distinguished two parts of the spawning migration, that is, one part being the migration from the place where the fish was released to the spawning grounds. The other part was a holding phase on the spawning grounds with little or no movements before spawning. The late salmon spent less of their total time on holding, 36.2%, and more on migration, 63.8%, compared with early migrating salmon, which distributed their time rather evenly between migration, 47.5%, and holding, 52.5%. In total, early salmon used 30% more time migrating and 156% more time holding than late salmon. Some Atlantic salmon (Salmo salar) fell back over the hydropower plant after release and got excluded from spawning. The fallback rates of transported, tagged spawners were higher in the early than in the late group in both years. The fallback rate in 2012 was 42.8% of the early group and 15.1% in the late. In 2013, there were 51.7 % fallbacks in the early group and 3.4% in the late. The salmon fell back on average 9days after being released in 2012 and 16days in 2013. A high mean daily discharge on the day of release increased the probability of becoming a fallback. Copyright (c) 2016 John Wiley & Sons, Ltd.

Place, publisher, year, edition, pages
John Wiley & Sons, 2016
Keywords
Atlantic Salmon, upstream migration, fallback, spawning, behaviour, timing
National Category
Biological Sciences
Research subject
Biology
Identifiers
urn:nbn:se:kau:diva-44678 (URN)10.1002/rra.3007 (DOI)000379952900023 ()
Available from: 2016-08-12 Created: 2016-08-12 Last updated: 2018-09-10Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-2220-1615

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