| 1. |
- Dekker, Willem, et al.
(författare)
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Assessment of the eel stock in Sweden, spring 2012 : First post-evaluation of the Swedish Eel Management Plan
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The population of the European eel Anguilla anguilla (L.) is in severe decline. In 2007, the European Union decided on a Regulation establishing measures for the recovery of the stock of European eel, obliging its Member States to implement a national Eel Management Plan by 2009. According to this Regulation, Member States will report to the Commission by July 2012, on the implementation of their Eel Management Plans and the progress achieved in protection and restoration. The current report provides an assessment of the eel stock in Sweden as of spring 2012, intending to feed into the coming Swedish post-evaluation reporting. In this report, the impacts on the stock are assessed - of fishing, restocking and of the mortality related to hydropower generation. Focus is on the quantification of the biomass of silver eel escaping (actual, potential and pristine) and the mortality endured by those eels during their lifetime. The assessment is broken down on a regional basis, with different impacts dominating in different areas. For the yellow eel fishery on the West Coast, the assessment presented in the Eel Management Plan is extrapolated to most recent years. Since 2009, the fishery has been restricted severely, and as of spring 2012, it has been closed. In the coming years, this reduction in fishing mortality will lead to a recovery of the West Coast stock to the best possible status given the depleted state of the whole international stock. For the stock in inland waters, a new assessment is presented, in which the dominant contribution from past restocking is put central. Recent changes (increased quantities, shift to west-ward flowing rivers) will have a delayed effect over the coming 10-20 years. The escapement biomass is expected to decrease until 2020 and then to restore to its current (low) value. Assuming that current conditions (2011) are continued, the impact of the fishery will slowly decline, while the impact of hydropower generation will stabilise/increase, at least until 2030. For the East Coast fishery on silver eel, a new assessment indicates a low mortality on a very large stock of silver eel derived from all over the Baltic. Recent restrictions have reduced the East Coast fishery. Protective actions in the whole Baltic (and their delayed effects) will determine the future trend in the East Coast fishery. Comparing the overall status of the national Swedish eel stock to the management targets, it is concluded that 1. Criteria of the Swedish Eel Management Plan have been fulfilled almost exactly; 2. Biomass escaping is about one-fourth of pristine escapement, below the minimum target of 40% set in the EU Regulation; and 3. The 2011 anthropogenic impacts are about half the allowable maximum (according to the ICES/WGEEL post-evaluation framework, at one-fourth of pristine escapement). Following the current closure of the West Coast fishery, the impacts will reduce to one-quarter of that allowable maximum.
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| 2. |
- Andersson, Jan, et al.
(författare)
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Status of the eel stock in Sweden in 2011
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report presents an overview of the eel stock in Sweden, as of spring 2011. The objective is to provide a comprehensive overview, avoiding scientific jargon as much as possible. Historical data series and recent distribution maps are shown, amongst others on recruitment, restocking, habitats and their productivity, fisheries, and the impact of hydropower generation. Indicators are derived for the state of the stock and for the impact of fishing and hydropower generation, before and after the implementation of the Eel Management Plan 2009. This report is also available in Swedish (Aqua reports 2011:1).; -- Föreliggande rapport ger en översikt av ålens beståndssituation som den ser ut våren 2011. Syftet med rapporten är att presentera en utförlig men lättläst översikt. Vi har försökt att, i görligaste mån, undvika vetenskaplig jargong och fackuttryck. Historiska dataserier över rekrytering, utsättning, uppväxtarealer och deras produktivitet presenteras samt givetvis fiskets omfattning och effekter. Effekten av vattenkraftsproduktion redovisas också. Med hjälp av dessa bakgrundsdata har olika beståndsindikatorer tagits fram och som beskriver beståndsstatus och effekten av fisket samt vattenkraftsproduktionen, såväl före som efter implementeringen av 2009-års Ålförvaltningsplan. Den här rapporten finns även på svenska (Aqua reports 2011:1)
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| 3. |
- Bergek, Sara, et al.
(författare)
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Fiskfångster och utsättningar av fisk
- 2012
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Ingår i: Vänern: årsskrift 2012. ; :73, s. 68-73
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Totalfångsten i yrkesfisket i Vänern ökade under 2011 med drygt 8 procent jämfört med 2010. Den viktigaste arten för yrkesfisket gösen, stod för cirka 32 procent av totala fångstens värde. Fångsten av siklöja och signalkräfta ökade medan fångsten av abborre, gädda, gös, öring, sik och ål minskade. De registrerade fritidsfiskarna fångade under 2011 totalt 70 ton, en minskning med 14 ton jämfört med 2010. Något fler lax- och öringsmolt sattes ut jämfört med föregående år. Även utsättningen av ål ökade, hela 605 000 stycken försträckta alternativt karantäniserade ålyngel sattes ut under 2011.
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| 4. |
- Dekker, Willem, et al.
(författare)
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Assessment of the fishing impact on the silver eel stock in the Baltic using survival analysis
- 2013
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Ingår i: Canadian Journal of Fisheries and Aquatic Sciences. - : Canadian Science Publishing. - 0706-652X .- 1205-7533. ; 70:12, s. 1673-1684
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Tidskriftsartikel (refereegranskat)abstract
- Restoration of the depleted stock of the European eel (Anguilla anguilla (L.)) requires anthropogenic impacts to bequantified, reduced, and controlled. In this article, we assess the impact of the silver eel fishery on the Baltic Coast in Sweden, applying survival analysis to 60 years of mark–recapture experiments, involving 8000 recaptures out of 18 000 releases. Thehazard of being recaptured (overall 46%) varies along the coast and declined substantially over the decades. But, most notably,the hazard for the individual diminishes strongly after the first kilometres en route. This individualized hazard disqualifies themore traditional mark–recapture methodology, which assumes random recaptures. We advocate the general use of survivalanalysis for conventional mark–recapture data. The result of our analysis indicates that the impact of the fishery just prior the2009 fishing restrictions was in the order of 10%—in itself well within sustainability limits, though only but one of the factors contributing to the mortality in the Baltic Sea.
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| 5. |
- Dekker, Willem
(författare)
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The 2003 Quebec Declaration of Concern About Eel Declines-11 Years Later: Are Eels Climbing Back up the Slippery Slope?
- 2014
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Ingår i: Fisheries. - : Wiley. - 0363-2415 .- 1548-8446. ; 39, s. 613-614
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In 2003, scientists gathered at the American Fisheries Society meeting in Québec and raised an urgent alarm in a Declaration of Concern about the state of eel stocks around the world, with less than 1% of juvenile resources remaining (as documented for northern temperate stocks). In the years since, precautionary protective measures have been implemented, monitoring and research have increased, and sustainable management methods have been developed. Recently, several juvenile resources have increased slightly. Reassembled in Québec in 2014, we reflect on what has been achieved since 2003 and what remains to be done.
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| 6. |
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| 7. |
- Knoop, Jesper, et al.
(författare)
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Association of lower muscle strength with self-reported knee instability in osteoarthritis of the knee: Results from the Amsterdam Osteoarthritis Cohort
- 2012
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Ingår i: Arthritis Care and Research. - : Wiley. - 2151-4658 .- 2151-464X. ; 64:1, s. 38-45
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Tidskriftsartikel (refereegranskat)abstract
- Objective To determine whether muscle strength, proprioceptive accuracy, and laxity are associated with self-reported knee instability in a large cohort of knee osteoarthritis (OA) patients, and to investigate whether muscle strength may compensate for impairment in proprioceptive accuracy or laxity, in order to maintain knee stability. Methods. Data from 283 knee OA patients from the Amsterdam Osteoarthritis cohort were used. Univariable and multivariable logistic regression analyses were performed to assess the association between muscle strength, proprioceptive accuracy (motion sense), frontal plane varus-valgus laxity, and self-reported knee instability. Additionally, effect modification between muscle strength and proprioceptive accuracy and between muscle strength and laxity was determined. Results. Self-reported knee instability was present in 67% of the knee OA patients and mainly occurred during walking. Lower muscle strength was significantly associated with the presence of self-reported knee instability, even after adjusting for relevant confounding. Impaired proprioceptive accuracy and high laxity were not associated with self-reported knee instability. No effect modification between muscle strength and proprioceptive accuracy or laxity was found. Conclusion. Lower muscle strength is strongly associated with self-reported knee instability in knee OA patients, while impairments in proprioceptive accuracy and laxity are not. A compensatory role of muscle strength for impaired proprioceptive accuracy or high laxity, in order to stabilize the knee, could not be demonstrated.
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| 8. |
- Knoop, Jesper, et al.
(författare)
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Identification of Phenotypes With Different Clinical Outcomes in Knee Osteoarthritis: Data From the Osteoarthritis Initiative
- 2011
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Ingår i: Arthritis Care and Research. - : Wiley. - 2151-4658 .- 2151-464X. ; 63:11, s. 1535-1542
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To identify subgroups or phenotypes of knee osteoarthritis (OA) patients based on similarities of clinically relevant patient characteristics, and to compare clinical outcomes of these phenotypes. Methods. Data from 842 knee OA patients of the Osteoarthritis Initiative were used. A cluster analysis method was performed, in which clusters were formed based on similarities in 4 clinically relevant, easily available variables: severity of radiographic OA, lower extremity muscle strength, body mass index, and depression. Univariable and multivariable regression analyses were used to compare phenotypes on clinical outcomes (pain and activity limitations), taking into account possible confounders. Results. Five phenotypes of knee OA patients were identified: "minimal joint disease phenotype," "strong muscle phenotype," "nonobese and weak muscle phenotype," "obese and weak muscle phenotype," and "depressive phenotype." The "depressive phenotype" and "obese and weak muscle phenotype" showed higher pain levels and more severe activity limitations than the other 3 phenotypes. Conclusion. Five phenotypes based on clinically relevant patient characteristics can be identified in the heterogeneous population of knee OA patients. These phenotypes showed different clinical outcomes. Interventions may need to be tailored to these clinical phenotypes.
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| 9. |
- Ragnarsson Stabo, Henrik, et al.
(författare)
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Fiskfångster och utsättning av fisk
- 2011
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Ingår i: Vänern - Årsskrift 2011. ; :66, s. 61-66
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Sandström, Alfred, et al.
(författare)
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Fiskfångster och utsättningar av fisk
- 2014
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Ingår i: Årsskrift 2014. ; :84, s. 77-83
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Totalfångsten i yrkesfisket i Vänern var oförändrad jämfört med 2012. Den viktigaste arten för yrkesfisket var gös, vilken stod för cirka 38 % av totala fångstens värde. Den näst viktigaste arten är siklöja (35 % av värdet). Fångsten av övriga viktiga arter som gädda, gös, lax, signalkräfta, öring och ål var på samma nivå som 2012. Fångsten av abborre minskade från 41 till 33 ton. De registrerade fritidsfiskarna fångade under 2013 totalt 69 ton, vilket är ungefär på samma nivå som 2012 men en minskning sett över längre tid. Totalt 267 276 smolt sattes ut vilket är över medelvärdet för den föregående femårsperioden. Även utsättningen av ål har ökat på senare år, 600 000 försträckta alternativt karantäniserade ålyngel sattes ut under både 2013 och 2014.
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