| 1. |
- Johnsson, Anna-Ida, et al.
(författare)
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Specific SCAR markers and multiplex real-time PCR for quantification of two Trichoderma biocontrol strains in environmental samples
- 2011
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Ingår i: BioControl. - : Springer Science and Business Media LLC. - 1386-6141 .- 1573-8248. ; 56, s. 903-913
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Tidskriftsartikel (refereegranskat)abstract
- Several strains from the genus Trichoderma (Ascomycetes, Hypocreales) are commercially used as biocontrol agents, e.g. in formulations containing the two Trichoderma strains IMI206039 (Hypocrea parapilulifera B.S. Lu, Druzhinina & Samuels) and IMI206040 (T. atroviride P. Karst). To quantify the presence of the two isolates after application, we developed primers for SCAR markers (Sequence-Characterised Amplified Region). In order to quantify both fungal strains simultaneously, we also designed fluorophore-labelled probes distinguishing the two strains, to be used in combination with the SCAR primers. In incubations of two different soils, artificially inoculated and maintained under controlled conditions, the quantification through amplification with the SCAR markers in qPCR and through colony-forming units from plate counting correlated well. Further tests of the markers on samples taken from a golf green treated with a product containing both strains indicated that the two biocontrol strains did not establish, either on the golf green or in the surrounding area.
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| 2. |
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| 3. |
- Von Rosen, Dietrich
(författare)
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Non-negative estimation of variance components in heteroscedastic one-way random-effects ANOVA models
- 2010
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Ingår i: Statistics. - : Informa UK Limited. - 0233-1888 .- 1029-4910. ; 44, s. 557-569
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Tidskriftsartikel (refereegranskat)abstract
- There is a considerable amount of literature dealing with inference about the parameters in a heteroscedastic one-way random-effects ANOVA model. In this paper, we primarily address the problem of improved quadratic estimation of the random-effect variance component. It turns out that such estimators with a smaller mean squared error compared with some standard unbiased quadratic estimators exist under quite general conditions. Improved estimators of the error variance components are also established.
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| 8. |
- Benavent-Celma, Clara, et al.
(författare)
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Current practices and emerging possibilities for reducing the spread of oomycete pathogens in terrestrial and aquatic production systems in the European Union
- 2022
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Ingår i: Fungal Biology Reviews. - : Elsevier. - 1749-4613 .- 1878-0253. ; 40, s. 19-36
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Tidskriftsartikel (refereegranskat)abstract
- Diseases caused by oomycete pathogens are a global threat to forestry, agriculture and aquaculture. Because of their complex life cycles, characterised by dormant resting structures that enable their survival for years under hostile environmental conditions, reducing the spread of oomycetes is a challenging task. In this review, we present an overview of this challenge, starting from the need to understand the natural and anthropogenic dispersal pathways of these pathogens. Focusing on the European Union, we explore current legislation that forms a backbone for biosecurity protocols against the spread of oomycetes through trade and transport. We discuss the options for prevention, containment and long-term management of oomycetes in different production settings, emphasising the importance of prevention as the most cost-efficient strategy to reduce the spread of these pathogens. Finally, we highlight some of the new and emerging technologies and strategies as potential tools in the integrated pest management of animal and plant diseases caused by oomycetes. We emphasise the urgency of actions to halt the global spread of these pathogens.
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| 9. |
- Ritter, Camila, et al.
(författare)
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Biodiversity assessments in the 21st century: The potential of insect traps to complement environmental samples for estimating eukaryotic and prokaryotic diversity using high-throughput DNA metabarcoding.
- 2019
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Ingår i: Genome. - : Canadian Science Publishing. - 1480-3321 .- 0831-2796. ; 62:3, s. 147-159
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Tidskriftsartikel (refereegranskat)abstract
- The rapid loss of biodiversity, coupled with difficulties in species identification, call for innovative approaches to assess biodiversity. Insects make up a substantial proportion of extant diversity and play fundamental roles in any given ecosystem. To complement morphological species identification, new techniques such as metabarcoding make it possible to quantify insect diversity and insect-ecosystem interactions through DNA sequencing. Here we examine the potential of bulk insect samples (i.e., containing many non-sorted specimens) to assess prokaryote and eukaryote biodiversity and to complement the taxonomic coverage of soil samples. We sampled 25 sites on three continents and in various ecosystems, collecting insects with Slam-traps (Brazil) and Malaise-traps (South Africa and Sweden). We then compared our diversity estimates with the results obtained with biodiversity data from soil samples from the same localities. We found a largely different taxonomic composition between the soil and insect samples, testifying to the potential of bulk insect samples to complement soil samples. Finally, we found that non-destructive DNA extraction protocols, which preserve insect specimens for morphological studies, constitute a promising choice for cost-effective biodiversity assessments. We propose that the sampling and sequencing of insect samples should become a standard complement for biodiversity studies based on environmental DNA.
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| 10. |
- Messing, Ingmar, et al.
(författare)
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Methods to estimate lettuce evapotranspiration in greenhouse conditions in the central zone of Chile
- 2009
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Ingår i: Chilean Journal of Agricultural Research. - 0718-5820. ; 69, s. 60-70
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluates five methods to estimate crop evapotranspiration in greenhouse conditions. It compares their performance in relation to the evapotranspiration directly determined from water balance measurements (ET(lys)) in an irrigated lettuce (Lactuca sativa L.) crop during 9 weeks. Daily values of the reference evapotranspiration (ETo) from Class A pan (CAP), Piche atmometers (ATM), Andersson evaporimeters (ANE), FAO-Radiation (FRE) and FAO-Penman-Monteith (PME) equations were compared. The methods showed similar temporal variations but at different ranges as follows: ANE < CAP < FRE < PME < ATM. Furthemore, ETo had a clear correlation with solar radiation. Crop coefficients (Kc = ET(lys)/ETo) varied somewhat amongst the methods, but trends were identified for two periods: in the first week, the overall mean Kc was 0.3 (+/- 0.1) and in weeks 2 to 9 on average 0.6 (+/- 0.3). The greenhouse values of Kc were lower than those generally adopted for lettuce in field conditions. In terms of irrigation design, crop evapotranspiration can be estimated by the methods in this study, on the condition that the appropriate crop coefficients are applied. The fact that ANE showed values closest to those of ETlys, along with cost and management convenience, makes it an advantageous alternative as compared to the other methods.
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| 11. |
- Granhall, Ulf, et al.
(författare)
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Bacterial community diversity in paper mills processing recycled paper
- 2010
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Ingår i: Journal of Industrial Microbiology & Biotechnology. - : Oxford University Press (OUP). - 1367-5435 .- 1476-5535. ; 37:10, s. 1061-1069
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Tidskriftsartikel (refereegranskat)abstract
- Paper mills processing recycled paper suffer from biofouling causing roblems both in the mill and final product. The total bacterial ommunity composition and identification of specific taxa in the process ater and biofilms at the stock preparation and paper machine areas in a ill with recycled paper pulp was described by using a DNA-based pproach. Process water in a similar mill was also analyzed to nvestigate if general trends can be found between mills and over time. acterial community profiles, analyzed by terminal-restriction fragment ength polymorphism (T-RFLP), in process water showed that the dominant eaks in the profiles were similar between the two mills, although the verall composition was unique for each mill. When comparing process ater and biofilm at different locations within one of the mills, we bserved a separation according to location and sample type, with the iofilm from the paper machine being most different. 16S rRNA gene clone ibraries were generated and 404 clones were screened by RFLP analysis. rouping of RFLP patterns confirmed that the biofilm from the paper achine was most different. A total of 99 clones representing all RFLP atterns were analyzed, resulting in sequences recovered from nine acterial phyla, including two candidate phyla. Bacteroidetes epresented 45% and Actinobacteria 23% of all the clones. Sequences with imilarity to organisms implicated in biofouling, like Chryseobacterium pp. and Brevundimonas spp., were recovered from all samples even though he mill had no process problems during sampling, suggesting that they re part of the natural paper mill community. Moreover, many sequences howed little homology to as yet uncultivated bacteria implying that aper mills are interesting for isolation of new organisms, as well as or bioprospecting.
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| 12. |
- Mulokozi, Deogratias Pius, et al.
(författare)
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Rural aquaculture : Assessment of its contribution to household income and farmers' perception in selected districts, Tanzania
- 2020
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Ingår i: Aquaculture Economics & Management. - : Informa UK Limited. - 1365-7305 .- 1551-8663 .- 1365-7313. ; 24:4, s. 387-405
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Tidskriftsartikel (refereegranskat)abstract
- Rural fish farming is being promoted as a good source of protein and income diversification to fight poverty and inequality. However, its actual contribution to these rural households and local community at large is little known. Through interviews with 89 farmers' and 6 key informants, we examined the contribution of rural fish farming to local farmers' household income and investigate farmers' perceptions, opportunities, and constraints towards fish farming in six districts of Tanzania. Results indicated that fish farming contributed on average 13% to household incomes and that it explained 5% of the variation of the household income while 84% of the variation was due to non-fish sources. The majority (79%) of the farmers wanted to continue with fish farming, 9% planned to quit, and 12% had not decided whether to continue or not. Conclusively, much higher aquaculture contribution towards rural development could be obtained if appropriate measures are taken.
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| 13. |
- Boman, Mattias, et al.
(författare)
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Kitesurfing
- 2011
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Ingår i: Friluftssport och Äventyrsidrott: Utmaningar för lärare, ledare och miljö i en föränderlig värld. - 9789144069135 ; , s. 194-199
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 14. |
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| 15. |
- Ekelöf, Joakim, et al.
(författare)
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Utvärdering av markfuktsensorer och prognosmodeller för styrning av bevattning i potatis
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Irrigation is often necessary to obtain a good economy on the farm. It can be hard to optimize irrigation even when the farmer has sufficient knowledge about the irrigation need and has the capacity to meet the need, due to uncertainty in weather forecasts and variability in selling prices for the crop. There are several technical tools to facilitate the decision-making regarding irrigation, such as forecasting models and soil moisture sensors. The evaluation assessed seven different models and sensors. The Danish irrigation forecasting model and the Watermark sensor showed the best result and are recommended for decision making in irrigation of quality potato in order to increase profitability. It is not profitable to use the soil moisture sensors in starch potato for facilitating decision making in irrigation due to low price and low demands on quality of the tubers
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| 16. |
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| 17. |
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| 18. |
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| 19. |
- Kahlert, Maria
(författare)
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Framtagande av gemensamt delprogram ”Kiselalger i vattendrag” : underlag för utformning av övervakningsprogram och verifiering av kiselalgsindex
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Även om det länge varit känt att kiselalger är användbara som indikatorer på miljöpåverkan är användandet av kiselalger i nationell och regional övervakning något av en ny företeelse. Att kiselalgerna är lätta och billiga att provta, att de kan provtas från fler olika typer av substrat/habitat än många andra biologiska indikatorer samt att de är mycket pålitliga indikatorer på vattenkemiska förhållanden har lett till att användandet av dem i miljöövervakningen nu ökar snabbt runt om i landet. En viktig första uppgift för utvecklingen av delprogrammet har därför varit att sammanställa information om metoder och tillförlitlighet och om vilken övervakning som sker för att skapa en bild av representativiteten hos de vattendrag som idag ingår i den nationella och regionala övervakningen av kiselalger. I samband med detta har vi även samlat in befintlig data, för att bygga upp det nationella datavärdskapet. Denna rapport sammanfattar dessa första steg i projektet och utgör ett viktigt underlag för delprogrammets slutliga utformning. Uppdraget har utförts med stöd av Naturvårdsverket från anslag 34:2 (Miljöövervakning m.m.), SLU:s råd för fortlöpande miljöanalys (FOMAR) ” Sveriges kiselalger” samt Institutionen för Vatten & Miljö, SLU
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| 20. |
- Kahlert, Maria
(författare)
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Jämförande test av kiselalgers och bottenfaunas lämplighet som indikatorer för närsaltshalt och surhet inom miljömålsuppföljningen
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Data från 321 enskilda vattendrag med information om vattenkemi, kiselalger och bottenfauna sammanställdes och analyserades för att jämföra kiselalgers och bottenfaunas lämplighet som indikatorer på närsaltshalt och surhet inom miljömålsuppföljningen. Vad gäller surhet gav kiselalgsindexet en mer precis och pålitlig överrensstämmelse med uppmätta pH-halter (både årsmedel och lägsta pH under året) än bottenfaunaindexen. Kiselalgsindexet hade även en lägre mellanårsvariation som var starkare kopplad till variationen i pH. Vi fann inga regionala skillnader i bedömningen av surhet med något av indexen. Vad gäller bedömningen av närsalter var skillnaderna mellan de jämförda indexen mindre men kiselalgerna svarade i allmänhet något bättre mot de uppmätta halterna av närsalter än bottenfaunaindexen. Vid en jämförelse av bedömning av ekologisk status för vattendrag som klassats med båda bedömningsgrunderna ger bottenfaunan i genomsnitt en högre status än kiselalgerna, särskilt i södra Sverige. Kiselalgernas bedömning av ekologisk status korrelerade bättre än bottenfaunan med statusklassning av näringsämnen (totalfosfor) i vattendrag . Vi konstaterar att skillnaderna i bedömning av ekologisk status med avseende på näring behöver undersökas vidare men att för miljömålsuppföljningens syfte att hitta en väl fungerande och kostnadseffektiv biologisk indikator på vattenkemiska variabler som surhet och närsaltshalt så verkar kiselalger bättre lämpade än bottenfauna.
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| 21. |
- Kahlert, Maria
(författare)
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Kiselalger i Västernorrland 2009/2010 : Undersökning av kiselalger inom den regionala miljöövervakningen
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Sammanfattningsvis så visar kiselalgsfloran i de undersökta vattendragen i Västernorrlands län att närsaltshalten i dessa vatten är lågt och den ekologiska statusklassen överlag är hög, inga förändringar i dessa avseenden fanns mellan 2009 och 2010. Angående surhet så visar kiselalgsmetoden att Viksbäcken har mycket surt vatten båda åren och är troligtvis antropogen försurat. Kiselalgsfloran i Kläppsjöbäcken och Kniptjärnsbäcken visar en tendens till surare vatten 2010 än 2009 vilket innebär att de under 2010 uppvisar en liten risk för försurning. Malmån uppvisar denna risk bara under 2009. Viksbäcken, som har undersökts tidigare, verkar ha blivit surare än 2006. De vanligaste kiselalgstaxa räknat till antal räknade skal var Achnanthidium minutissimum grupp II (medelbredd 2,2-2,8μm), Fragilaria gracilis Østrup och Eunotia exigua (Brebisson ex Kützing) Rabenhorst. F. gracilis hörde också, tillsammans med Tabellaria flocculosa (Roth) Kützing och Gomphonema exilissimum (Grun.) Lange-Bertalot & Reichardt, till de mest frekventa kiselalgstaxa som förekom i nästan alla prover förutom en. Alla dessa taxa indikerar närsaltsfattiga vatten, E. exigua och T. flocculosa även sura förhållanden. Alla tillhör också de vanliga taxa för hela Sverige
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| 22. |
- Kahlert, Maria
(författare)
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Kiselalgsundersökning i Blekinge län 2010
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Sammanfattningsvis så visar kiselalgsfloran i de undersökta vattendragen i Blekinge län att närsaltshalten i dessa vatten är något högre än i oligotrofa vattendrag, men den ekologiska statusklassen ligger fortfarande mellan hög och god status förutom i Mörrumsån Johannesfors, där den ligger mellan god och måttlig status. Angående surhet så visar kiselalgsmetoden att alla lokaler har nära neutrala eller alkaliska förhållanden förutom Lyckebyån Kättilsmåla nedströms Lillåns tillflöde och Ronnebyån nedströms Kallinge som har något surare förhållanden mellan måttligt surt och nära neutralt. De vanligaste kiselalgstaxa räknat till antal räknade skal var Achnanthidium minutissimum grupp II (medelbredd 2,2-2,8μm), Achnanthidium minutissimum grupp III (medelbredd > 2,8μm), Aulacoseira ambigua (Grunow) Simonsen och Karayevia oblongella M. Aboal. Om man istället definierar en vanlig kiselalgstaxon som en som förekommer i alla undersökta prover så var de tre andra taxa som kom först: Fragilaria gracilis Østrup, Psammothidium abundans Bukhtiyarova och Aulacoseira pseudodistans Lange-Bertalot 'manuskriptnamen', men de förkom inte med så hög dominans som de förut nämnda. Några av de vanliga taxa indikerar närsaltsfattiga vatten, andra något högre närsaltshalter. Några av de vanliga taxa föredrar neutrala förhållanden, andra mera sura. Alla tillhör också vanliga taxa för hela Sverige
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| 23. |
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| 24. |
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| 25. |
- Lode, Elve
(författare)
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Introduction
- 2011
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Ingår i: Forest management and the Water Cycle. An Ecosystem-Based Approach. ; :212, s. 333-334
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 26. |
- Lode, Elve
(författare)
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Typological Up-Scaling of Wooded Peatlands
- 2011
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Ingår i: Forest Managemnt and the Water Cycle. An Ecosystem-Based Approach. - 9789048198337 ; :212, s. 471-496
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 27. |
- Lundh, Torbjörn, et al.
(författare)
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In search for protein sources: Evaluating an alternative to the traditional fish feed for Arctic charr (Salvelinus alpinus L.)
- 2018
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 486, s. 253-260
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Tidskriftsartikel (refereegranskat)abstract
- Traditional sources of protein in fish feed for salmonids, such as fishmeal, face sustainability problems. Therefore, ingredients not attractive for human consumption are increasingly being considered for the development of future feeds. However, it is uncertain how this alternative range of ingredients will affect fish growth, quality and consumer opinion. In this experimental study, we tested a new fish feed on Arctic charr, containing a protein mixture from the Baltic Sea and yeast, all ingredients unattractive for human consumption. This feed comprised of sprat (Sprattus sprattus) and herring (Clupea harengus), blue mussels (Mytilus edulis) and baker's yeast (Saccharomyces cerevisiae), in a ratio of three parts to the whole. Fish fed with this feed grew 11.5% less than the control group. The digestibility and microscopy analysis of the faeces suggested a lower digestibility of the test feed, presumably caused by the fish's inability to utilize the nutrients from the yeast cells. Consumers' perceptions of the final product were evaluated through a sensory evaluation, indicating no differences in scores of fillet quality between the two treatments. Potential implications of these results are discussed in context of feed composition, quality and other factors including species biology and season, which are relevant topics in the discussions on feed sustainability. Statement of relevance: Evaluating a feed mix unattractive for human consumption.
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| 28. |
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| 29. |
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| 30. |
- Alsanius, Beatrix, et al.
(författare)
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EHEC's öde på frilandsodlade grönsaker
- 2010
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Ingår i: LTJ-fakultetens faktablad.
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Annan publikation (populärvet., debatt m.m.)abstract
- Sjukdomsutbrott orsakade av tarmsmittor (t.ex. Salmonella, Campylobacter, E. coli, Shigella, Norovirus) har tidigare främst förknippats med animaliska produkter. Under de senaste åren har dock utbrott relaterade till frukt och grönt ökat; 49 frukt- och grönt relaterade utbrott med ca 2500 sjukdomsfall registrerades under tiden 1997-2009. Mörkertalet är dock stort och kan beroende på sjukdomsalstraren vara 4-10 gånger högre. Fram till 2004 klassades hotet från frukt och grönt som ringa. Det svenska utbrottet av EHEC, en aggressiv form av E. coli, i samband med produktion av isbergssallad under hösten 2005, satte problemet med fekal förorening i frukt och grönt på den svenska agendan. Smittorna kan överföras i hela kedjan från jord till bord och problemet är mest påtagligt för frukt och grönt som konsumeras rå eller med minimal tillredning. Organisk gödsel och bevattningsvatten har identifierats som huvudsakliga smittkällor vid odling av frilandskulturer, men det finns även andra smittkällor, t.ex. vilda djur, husdjur och människor. För att förhindra dessa utbrott är det viktigt att bryta smittcykeln. Vi har studerat om E. coli, i synnerhet EHEC, överlever på grönt, när smittan överförts med bevattningsvatten. Vi använde oss av en EHEC-stam som inte kan framkalla sjukdom, men som i övrigt har de för EHEC unika miljömässiga egenskaperna (biokemisk EHEC). Enligt våra resultat minskar förekomsten av biokemisk EHEC med ökande tidsintervall mellan bevattnings- och skördetillfälle. Minskningen beror på halten av biokemisk EHEC i bevattningsvattnet. Val av E. coli-stam för provokation och analyssätt är väsentliga. För att undvika sjukdomsutbrott i samband med odling av persilja, ska ett intervall av 72 timmar mellan bevattning med smittat bevattningsvatten och skörd inte underskridas
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| 31. |
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| 32. |
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| 33. |
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| 34. |
- Casimir, Justin, et al.
(författare)
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Småskalighet som ett medel för att bana väg för framtidens livsmedel?
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The food value chain system in Sweden is well established making it hard for small companies to develop new products and even harder to create new food supply systems Obstacles could lay at the beginning of the chain (food production or processing), at the end (marketing, consumer) or could even be related to the legislative regulation framing the food supply chain. Smaller actors often lack resources and networks to develop their sector. However, their degree of creativity, innovativeness, and engagement is high, and their energy is needed in the development of new sustainable food value chains.The aim of this project was to develop and apply a methodology for evaluating food value chains, focusing on profitable small-scale production systems in Sweden that show potential for fast development of new products that quickly reach the market. The work also included identifying Swedish raw food materials with growth potential and to identify how they could come into greater demand. Ten food value chains with high development potential in Sweden and for export were mapped and the main bottlenecks briefly described. Three food chains where selected based on a potential-difficulty-benefit matrix. The three selected food value chains were: (i) Hops, (ii) Swedish forest berries, and (iii) Land-based fish farming. These three food value chains where further studied looking at the whole value chain, from production to end consumer. Through literature review and contacts with relevant stakeholders (telephone interview, face-to-face interview, or workshop) the bottlenecks were clarified and potential solutions for increased demand where identified.Swedish hops production is carried out by passionate and engaged smaller actors, mostly on a hobby level, and the hops is used as an ingredient for beer. Germany and the USA produce about 75% of the worldwide production These hops varieties are not adapted to the Swedish climate and therefore result in a low volume and poor quality. However, domestic varieties have been grown in the past giving better yield under Swedish climate conditions. More work is needed to characterize the quality of Swedish hops. At the present time, knowledge about the characteristics of Swedish hops is low, explaining the lack of interest from brewers. In Sweden most hops are harvested by hand, making it nearly impossible to be profitable on the market. The mechanization of the harvesting step is necessary to move Swedish hops from a hobby to a commercial activity. No solutions are available on the Swedish market, RISE together with SLU is looking to develop a hops harvester fulfilling Swedish and EU regulations and adapted to small scale cultivation. At the end of the value chain, innovative products could increase the need for Swedish hops, for example by developing beers brewed with fresh hops. Moreover, hops have antiseptic characteristics and could potentially be used in other food products than beer.Only about four percent of the berries that are produced by the Swedish forests every year are picked. The largest volumes picked are for bilberry (Swedish: blåbär), lingonberry, and cloudberry and most of them are washed and frozen in Sweden. Processing of berries, however, has to a large extent moved out of the country while the products produced for the Swedish market are quite traditional, low-processed foods such as jams, juices and dessert soups. The majority of the Swedish berries mainly bilberries due to their nutritional content are exported and are further processed into value added powders or extracts in Asia and Europe. In Sweden this kind of value chain is under developed largely due to knowledge barriers and to the currently very traditional market. However, there is a great consumer interest in berries and they have a perceived healthiness also in Sweden. Consumers are also increasingly aware of the origin of berries used as ingredients in products such as jams, purees and juice, as well as in health food products. To fill this gap between consumer interest/demand and raw materials available new businesses can be developed. To facilitate such development there is a need for knowledge generation and transfer along the whole value chain (picking, processing, product development and consumer studies), which can be generated by starting up new innovation and research projects. It is also of importance to facilitate networking, for example in the ‘berry network’ (coordinated by RISE), as the creation of a new value chain will require different businesses to cooperate. Also, product development projects will need support for testing, pilot production, and possibly in finding investment funding for new equipment.Land-based fish farming is small in comparison to traditional fish farming in Sweden, but several actors see a great potential in this system which has a lower impact on the environment compared to conventional fish farms. For instance, the Swedish farmer federation (LRF) has invested in a land-based fish farm recently. As in other EU-countries, the number of active farms in Sweden is decreasing and some see the potential to recycle unused animal stables into fish farms. A major bottleneck for land-based fish farming is current legislation as it is based on conventional fish farming and therefore does not consider the environmental benefits of land-based systems. Knowledge should be spread to relevant authorities and policy makers to open a dialog and facilitate the development of a relevant regulatory framework. Regarding the production phase, access to sustainably produced feed and technical competence are lacking. Moreover, as the technology is costly learning through trial and error would not be recommended. A testbed dedicated to land-based fish farming could support companies who wish to try modifications to their system. Furthermore, smaller producers have difficulties in finding processing solutions for their products; e.g. slaughterhouses and conditioning. Two potential solutions would be to develop a land-based fish farm cooperative and/or mobile systems that could take care of smaller productions. Finally, the competition on the market is tough as land-based fishes are competing with large-scale conventional fish farms from Norway and Asia. To overcome this bottleneck, the sector could develop its own certification as well as increasing the consumers awareness and knowledge.Some conclusions could be applied to all the studied food chains. For instance, each value chain can be seen as a puzzle with many pieces. In order to develop new food value chains many separate pieces need to fall into place. Therefore, it is necessary to increase collaboration between stakeholders but also to have a stakeholder driven coordination of this collaboration. The stakeholders within the developing value chains often do not have all the resources to carry out this task, especially if they are small businesses. The development of cooperatives also seems to be a solution to overcome bottlenecks in the studied food chains. Likewise, logistics in the developing value chains have a great margin for improvement. Furthermore, this project focused on value chains where food commodities are the end product but investigating the potential for non-food uses would also be of interest.The method used in this project can be replicated to other value chains with potential of development. It would help the users to get a holistic view of the current bottlenecks and facilitate contact between stakeholders. The list of bottlenecks can be followed up and used as an indicator to evaluate if the value chain in moving forward.
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| 35. |
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| 36. |
- Kreuger, Jenny, et al.
(författare)
-
Bekämpningsmedel i vattendrag från områden med odling av trädgårdsgrödor under 2008
- 2009
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Den nuvarande miljöövervakningen av bekämpningsmedel (växtskyddsmedel) är främst inriktad mot att undersöka eventuellt läckage av växtskyddsmedel som används inom jordbruket. Däremot saknar vi kunskap om hur dessa medel uppträder i miljön vid användning inom trädgårdsodlingen. I vissa delar av södra Sverige finns betydande områden med frilandsodling av bär, frukt och grönsaker, samt växthusanläggningar. Växthus har i vissa sammanhang betraktats som ’slutna miljöer’. Detta har gjort att man inte alltid haft samma höga krav när man bedömt risken för skadliga effekter i omgivande vatten av växtskyddsmedel som används i just växthus jämfört med användning på våra åkrar.Syftet med undersökningen var att utveckla kunskapen om eventuellt läckage av växtskyddsmedel som används inom frilandsodling av trädgårdsgrödor och i växthus till vatten. Undersökningen, som genomfördes under 2008, är den hitintills mest omfattande när det gäller antalet undersökta växtskyddsmedel i svenska vattendrag. Analyserna omfattade 126 enskilda substanser, varav 39 inte undersökts tidigare inom den nationella miljöövervakningen.I undersökningen ingick provtagning i vattendrag från sex områden med betydande odling av trädgårdsgrödor. Frilandsodling av bär förekom i avrinningsområdet i SÖ Småland, grönsaker i NÖ Skåne och frukt i SÖ Skåne. Växthusodling förekom i avrinningsområdet i V Skåne och NV Skåne. I dessa områden togs ett tiotal prover per område under perioden maj-oktober 2008. Därutöver analyserades ett tjugotal vattenprover från ett av de områden som ingår i den ordinarie miljöövervakningen (område N 34 i Halland). Ett fåtal prover togs också på överskottsvatten från växthus.Totalt påträffades 78 av de 126 substanser som ingick i undersökningen, med en spridning på mellan 24 och 44 substanser i vatten från de enskilda områdena. Flest substanser och högre halter påträffades i området med intensiv grönsaksodling i NÖ Skåne, från området i Halland och från de två områdena med växthusodling. Lägre halter och färre substanser återfanns i vatten från området i SÖ Småland med odling av jordgubbar och från området i SÖ Skåne med äppelodlingar.Riktvärdet överskreds i flertalet prov som samlades in från området i NÖ Skåne och i samtliga prov från de två växthusområdena (V Skåne och NV Skåne), med högst överskridanden i de två sistnämnda områdena. Insektsmedlet imidakloprid var den substans som oftast återfanns över riktvärdet i denna undersökning. Vissa av de substanser som påträffades i förhöjda halter i vatten från områden med växthusodling återfanns också i de prover som togs på överskottsvatten från växthus. Även substanser med en betydande användning i prydnadsväxtodling i växthus påträffades i vattendraget i V Skåne. Resultaten visar att det finns läckage av växtskyddsmedel från svenska växthus. Arbete med att identifiera möjliga riskmoment i samband med växtskyddsarbete i växthus, i syfte att minska förlusterna av växtskyddsmedel till omgivande vatten, bör därför vidareutvecklas.
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| 37. |
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| 38. |
- Bauer, Barbara, et al.
(författare)
-
Reducing eutrophication increases spatial extent of communities supporting commercial fisheries : a model case study
- 2018
-
Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 75:4, s. 1306-1317
-
Tidskriftsartikel (refereegranskat)abstract
- In this study we investigate if eutrophication management has the potential to substantially affect which areas are going to be most suitable for commercial fishing in the future. We use a spatial ecosystem model, forced by a coupled physical-biogeochemical model, to simulate the spatial distribution of functional groups within a marine ecosystem, which depends on their respective tolerances to abiotic factors, trophic interactions, and fishing. We simulate the future long-term spatial developments of the community composition and their potential implications for fisheries under three different nutrient management scenarios and changing climate. The three nutrient management scenarios result in contrasting developments of bottom oxygen concentrations and phytoplankton abundance, with substantial effects on fish production. Nutrient load reduction increases the spatial extent of the areas suitable for the commercially most valuable demersal fish predator and all types of fisheries. This suggests that strategic planning of fishery management strategies could benefit from considering future changes in species distributions due to changes in eutrophication. We show that combining approaches from climate research, physical oceanography, biogeochemistry, biogeography, and trophic ecology with economical information provides a strong foundation to produce scientific knowledge that can support a multisectoral management of ecosystems.
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| 39. |
- Borthwick, Louisa, et al.
(författare)
-
Svensk konsumtion av sjömat
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Den här rapporten visar att det är möjligt att få fram tillförlitlig statistik över svensk sjömatskonsumtion för alla arter utom sill och skarpsill på en detaljgrad som tidigare saknats, trots de dataluckor som finns.Sjömatskonsumtionen i Sverige beräknas ligga på 25 kg per capita hel sjömat, vilket motsvarar 12,5 kg ätlig sjömat eller knappt två portioner i veckan. Vi äter mindre sjömat än för fem år sedan.Upp mot 80 olika sjömatsarter finns på den svenska marknaden, men de tio vanligaste står för 80 procent av konsumtionen. Mest äter svenskar av lax, sill, torsk och räkor.Knappt 30 procent av det som äts kommer från den inhemska produktionen av sjömat från yrkes- och fritidsfiske, samt odling. Den inhemska produktionen kan ses som Sveriges teoretiska självförsörjningsgrad av sjömat. Drygt 70 procent importeras alltså och då främst med Norge, Danmark och Kina som avsändarland. Från den svenska produktionen är det främst sill, skarpsill, regnbåge och den fisk som rapporteras under koden ”Fryst fisk i.a.n.” i tulltaxan, som exporteras. Figuren nedan visar fördelningen mellan import och inhemsk produktion.Siffran på sillkonsumtion är mycket osäker på grund av att den officiella statistiken håller låg kvalitet. Sill är den volymmässigt och ekonomiskt viktigaste arten i svenskt fiske och den är viktig för svensk konsumtion. Det är därmed anmärkningsvärt att data kring fisket och handeln är så bristfällig.Det är genomförbart att ta fram statistiken på årlig basis för att följa trenden för sjömatskonsumtion över tid, både totalt och utvecklingen av enskilda arter. Metoden som utvecklats här förenklar detta avsevärt, men det krävs fortfarande en del manuell justering och bearbetning av befintliga dataset, samt kunskap om branschen.
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| 40. |
- Charisiadou, S., et al.
(författare)
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Coastal aquaculture in Zanzibar, Tanzania
- 2022
-
Ingår i: Aquaculture. - : Elsevier. - 0044-8486 .- 1873-5622. ; 546
-
Tidskriftsartikel (refereegranskat)abstract
- This study provides an overview of the multi-sectoral coastal aquaculture development in Zanzibar (Tanzania) over the last thirty years based on empirical evidence from interviews, field observations, policy reports and literature reviews. Despite the immense potential of aquaculture for food and livelihoods, only seaweed farming has so far established into commercial-scale production. This activity is dominated by women and became widespread in the early 1990s as a small but regular source of income. However, seaweed farming constraints such as frequent seaweed die-offs, as well as economic and institutional constraints inhibit its development. Other types of aquaculture activities such as fish farming, mud crab fattening, half-pearl farming, sea cucumber farming and sponge and coral cultures are under development with limited production or in experimental stages. Common constraints among these activities are economic limitations, lack of technical infrastructure and skills, small and irregular production, and limited trade and market availabilities. At the same time, there is a lack of sufficient management and monitoring systems, while there are no formal regulations or clear strategies to boost aquaculture at the national level. In addition, new aquaculture initiatives are often dominated by donor-driven projects instead of local entrepreneurships. This situation does not encourage engagement in aquaculture and thus such activities are outcompeted by other already established sectors (e.g. agriculture and fisheries). We conclude that aquaculture has great potential to evolve due to high environmental capacity. Nevertheless, achieving profitable production and a stronger commitment within local communities, as well as developing effective mariculture governance through support mechanisms and clear strategies to boost the sector at the national level, are essential for sustainable mariculture development in Zanzibar.
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| 41. |
- Eero, Margit, et al.
(författare)
-
Food for Thought Eastern Baltic cod in distress : biological changes and challenges for stock assessment
- 2015
-
Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 72:8, s. 2180-2186
-
Tidskriftsartikel (refereegranskat)abstract
- The eastern Baltic (EB) cod (Gadus morhua) stock was depleted and overexploited for decades until the mid-2000s, when fishing mortality rapidly declined and biomass started to increase, as shown by stock assessments. These positive developments were partly assigned to effective management measures, and the EB cod was considered one of the most successful stock recoveries in recent times. In contrast to this optimistic view, the analytical stock assessment failed in 2014, leaving the present stock status unclear. Deteriorated quality of some basic input data for stock assessment in combination with changes in environmental and ecological conditions has led to an unusual situation for cod in the Baltic Sea, which poses new challenges for stock assessment and management advice. A number of adverse developments such as low nutritional condition and disappearance of larger individuals indicate that the stock is in distress. In this study, we (i) summarize the knowledge of recent changes in cod biology and ecosystem conditions, (ii) describe the subsequent challenges for stock assessment, and (iii) highlight the key questions where answers are urgently needed to understand the present stock status and provide scientifically solid support for cod management in the Baltic Sea.
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| 42. |
- Eklöf, Johan S., 1978-, et al.
(författare)
-
Effects of seasonal spawning closures on pike (Esox lucius L.) and perch (Perca fluviatilis L.) catches and coastal food webs in the western Baltic Sea
- 2023
-
Ingår i: Fisheries Research. - : Elsevier BV. - 0165-7836 .- 1872-6763. ; 263
-
Tidskriftsartikel (refereegranskat)abstract
- Marine protected areas have become one of the main tools in the battle to curb marine biodiversity loss and habitat degradation. Yet, implementation of permanent fishery closures has often generated resource user conflicts that ultimately undermine conservation goals. Here we assessed the influence of an alternative and often more accepted measure – seasonal fish spawning closures – on large predatory fish and coastal food webs in the western Baltic Sea (Sweden). In spring 2017, we conducted a multivariable field survey in 11 seasonal closures and 11 paired references areas open to fishing. In each area, pike was sampled through angling, and perch and mesopredators through gillnet surveys. To assess trophic cascades, we measured zooplankton abundance and loss of tethered gammarids from predation. Catches per unit effort of northern pike (Esox lucius) – the main target species in recreational fisheries – were ca. 2.5 times higher per unit effort in closures than reference areas; an effect that may be caused by higher abundance and/or higher catchability of pike in the absence of fishing. Catch and weight per unit effort of the more common predator European perch (Perca fluviatilus), and the mesopredators roach (Rutilus rutilus) and three-spined stickleback (Gasterosteus aculeatus) in survey nets were, however, unaffected by closures. Moreover, a previously hypothesized trophic cascade from perch to zooplankton via three-spined stickleback was supported by the analyses, but appeared independent of closures. Yet, predation risk for tethered gammarid amphipods (a prey of stickleback and an important grazer on macroalgae) was three times higher in fished areas than in closures; a cascading closure effect that may potentially be caused by small predatory fish being less active in protected areas to avoid pike predation. Overall, our results suggest that spawning closures impact pike abundance and/or behavior and could help limit the effects of fishing, but that more research is needed to disentangle i) what mechanism(s) that underlie the protection effect on pike catches, ii) the apparently weaker closure impacts on other fish species, as well as iii) the potential for cascading effects on lower trophic levels. Therefore, new seasonal spawning closures should be implemented in addition to (and not instead of) much-needed permanent closures, which have well-known effects on the wider ecosystem.
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| 43. |
- Fulton, Christopher J., et al.
(författare)
-
Macroalgal meadow habitats support fish and fisheries in diverse tropical seascapes
- 2020
-
Ingår i: Fish and Fisheries. - : Wiley. - 1467-2960 .- 1467-2979. ; 21:4, s. 700-717
-
Tidskriftsartikel (refereegranskat)abstract
- Canopy-forming macroalgae can construct extensive meadow habitats in tropical seascapes occupied by fishes that span a diversity of taxa, life-history stages and ecological roles. Our synthesis assessed whether these tropical macroalgal habitats have unique fish assemblages, provide fish nurseries and support local fisheries. We also applied a meta-analysis of independent surveys across 23 tropical reef locations in 11 countries to examine how macroalgal canopy condition is related to the abundance of macroalgal-associated fishes. Over 627 fish species were documented in tropical macroalgal meadows, with 218 of these taxa exhibiting higher local abundance within this habitat (cf. nearby coral reef) during at least one life-history stage. Major overlap (40%-43%) in local fish species richness among macroalgal and seagrass or coral reef habitats suggest macroalgal meadows may provide an important habitat refuge. Moreover, the prominence of juvenile fishes suggests macroalgal meadows facilitate the triphasic life cycle of many fishes occupying diverse tropical seascapes. Correlations between macroalgal canopy structure and juvenile abundance suggests macroalgal habitat condition can influence levels of replenishment in tropical fish populations, including the majority of macroalgal-associated fishes that are targeted by commercial, subsistence or recreational fisheries. While many macroalgal-associated fishery species are of minor commercial value, their local importance for food and livelihood security can be substantial (e.g. up to 60% of landings in Kenyan reef fisheries). Given that macroalgal canopy condition can vary substantially with sea temperature, there is a high likelihood that climate change will impact macroalgal-associated fish and fisheries.
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| 44. |
- Hansson, Sture, et al.
(författare)
-
Competition for the fish - fish extraction from the Baltic Sea by humans, aquatic mammals, and birds
- 2018
-
Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 75:3, s. 999-1008
-
Tidskriftsartikel (refereegranskat)abstract
- Seals and fish-eating birds have increased in the Baltic Sea and there is concern that they compete with fisheries. Using data from around year 2010, we compare consumption of different fish species by seals and birds to the catch in the commercial and recreational fishery. When applicable this is done at the geographical resolution of ICES subdivisions. Predation by birds and mammals likely has limited impact on the populations of the commercially most important species (herring, sprat, and cod). In the central and southern Baltic, seals and birds consume about as much flatfish as is caught by the fishery and competition is possible. Birds and seals consume 2-3 times as much coastal fish as is caught in the fishery. Many of these species are important to the fishery (e. g. perch and whitefish) and competition between wildlife and the fishery is likely, at least locally. Estimated wildlife consumption of pike, sea trout and pikeperch varies among ICES subdivisions and the degree of competition for these species may differ among areas. Competition between wildlife and fisheries need to be addressed in basic ecosystem research, management and conservation. This requires improved quantitative data on wildlife diets, abundances and fish production.
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| 45. |
- Hekim, Zeynep, et al.
(författare)
-
The role of climate and fisheries on the temporal changes in the Bothnian Bay foodweb
- 2016
-
Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 73:7, s. 1739-1749
-
Tidskriftsartikel (refereegranskat)abstract
- Climate change, eutrophication, and fishing are main pressures associated with changes in the abiotic and biotic environment in several sub-basins of the Baltic Sea. Identifying the nature of such changes is of relative importance for fisheries and environmental management. The Bothnian Bay is the northernmost sub-basin in the Baltic Sea and the responses of the foodweb to long-term changes in combined pressures have not been investigated. In this study, we explore long-term changes in the Bothnian Bay foodweb, represented by key species across all trophic levels over the past 34 years, and identify potential environmental and anthropogenic drivers. The results indicate that salinity is the most important driver to explain changes in the composition of the offshore biota in the Bothnian Bay. These changes are probably driven by indirect effects of salinity rather than bottom-up effects. A decline in the herring spawning-stock biomass was most plausibly attributed to an increased competition for food due to a parallel increase in vendace, which uses the same food resources (zooplankton and zoobenthos) and may benefit from declining salinity due to its limnic origin. A strong increase in the abundance of grey seal and ringed seal populations was seen in the late 2000s but was not related to any of the pressure variables analysed. Temperature and nutrients were not identified as important drivers of changes in the overall biota. Our study explores correlative relationships between variables and identifies potential interactions in the foodweb to generate hypotheses for further studies.
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| 46. |
- Hernroth, Bodil, 1951-, et al.
(författare)
-
Impact of ocean acidification on antimicrobial activity in gills of the blue mussel (Mytilus edulis)
- 2016
-
Ingår i: Fish and Shellfish Immunology. - : Elsevier. - 1050-4648 .- 1095-9947. ; 55, s. 452-459
-
Tidskriftsartikel (refereegranskat)abstract
- Here, we aimed to investigate potential effects of ocean acidification on antimicrobial peptide (AMP) activity in the gills of Mytilus edulis, as gills are directly facing seawater and the changing pH (predicted to be reduced from ∼8.1 to ∼7.7 by 2100). The AMP activity of gill and haemocyte extracts was compared at pH 6.0, 7.7 and 8.1, with a radial diffusion assay against Escherichia coli. The activity of the gill extracts was not affected by pH, while it was significantly reduced with increasing pH in the haemocyte extracts. Gill extracts were also tested against different species of Vibrio (V. parahaemolyticus, V. tubiashii, V. splendidus, V. alginolyticus) at pH 7.7 and 8.1. The metabolic activity of the bacteria decreased by ∼65–90%, depending on species of bacteria, but was, as in the radial diffusion assay, not affected by pH. The results indicated that AMPs from gills are efficient in a broad pH-range. However, when mussels were pre-exposed for pH 7.7 for four month the gill extracts presented significantly lower inhibit of bacterial growth. A full in-depth proteome investigation of gill extracts, using LC-Orbitrap MS/MS technique, showed that among previously described AMPs from haemocytes of Mytilus, myticin A was found up-regulated in response to lipopolysaccharide, 3 h post injection. Sporadic occurrence of other immune related peptides/proteins also pointed to a rapid response (0.5–3 h p.i.). Altogether, our results indicate that the gills of blue mussels constitute an important first line defence adapted to act at the pH of seawater. The antimicrobial activity of the gills is however modulated when mussels are under the pressure of ocean acidification, which may give future advantages for invading pathogens.
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| 47. |
- Hornborg, Sara, et al.
(författare)
-
Frisk med fisk utan risk? : Betydelsen av svensk konsumtion av sjömat för hälsa och miljö
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Seafood is a diverse food commodity, comprising of over 2 500 species from capture fisheries and over 600 species from farming, with vast differences between production methods. Dietary advice often includes recommendations to increase consumption of seafood, based on health benefits and that seafood may be produced with less environmental impacts and resources use compared to many other animal-based foods. However, at the same time, there are frequent media alarms related to potential health risks (some species have diet restrictions) and destructive production practices from both fisheries and aquaculture. As a result, there is often confusion on which seafood to eat or not to eat.The aim of this report is primarily to collate available information on health risks and benefits of Swedish seafood consumption, and to combine this with environmental aspects (focus on carbon footprint).Around 40 seafood products consumed in Sweden were included in the analysis. Potential health risks could only be included qualitatively, since the collected data is risk-based and thus not all products are sampled. It was found that the nutritional content and carbon footprint vastly differ between species. There were also several data gaps identified, such as the need for more detailed data on performance from different production systems. The combined assessment of nutritional value and carbon footprint categorised some species as win-win in terms of nutritional content and environmental pressures (such as small pelagic fish), while others could be more categorised as having less nutritional value and with high environmental costs (such as Northern prawn) respectively.The report provides decision support for further data collection needed to enable combined assessment of nutritional risks, benefits and environmental sustainability of seafood products. Results may be used to discuss suitable level of details of dietary advice.
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| 48. |
- Kininmonth, Stuart, et al.
(författare)
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Is Diversity the Missing Link in Coastal Fisheries Management?
- 2022
-
Ingår i: Diversity. - : MDPI AG. - 1424-2818. ; 14:2
-
Tidskriftsartikel (refereegranskat)abstract
- Fisheries management has historically focused on the population elasticity of target fish based primarily on demographic modeling, with the key assumptions of stability in environmental conditions and static trophic relationships. The predictive capacity of this fisheries framework is poor, especially in closed systems where the benthic diversity and boundary effects are important and the stock levels are low. Here, we present a probabilistic model that couples key fish populations with a complex suite of trophic, environmental, and geomorphological factors. Using 41 years of observations we model the changes in eastern Baltic cod (Gadus morhua), herring (Clupea harengus), and Baltic sprat (Sprattus sprattus balticus) for the Baltic Sea within a Bayesian network. The model predictions are spatially explicit and show the changes of the central Baltic Sea from cod- to sprat-dominated ecology over the 41 years. This also highlights how the years 2004 to 2014 deviate in terms of the typical cod–environment relationship, with environmental factors such as salinity being less influential on cod population abundance than in previous periods. The role of macrozoobenthos abundance, biotopic rugosity, and flatfish biomass showed an increased influence in predicting cod biomass in the last decade of the study. Fisheries management that is able to accommodate shifting ecological and environmental conditions relevant to biotopic information will be more effective and realistic. Non-stationary modelling for all of the homogeneous biotope regions, while acknowledging that each has a specific ecology relevant to understanding the fish population dynamics, is essential for fisheries science and sustainable management of fish stocks.
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| 49. |
- Kulatska, Nataliia, et al.
(författare)
-
Size-selective competition between cod and pelagic fisheries for prey
- 2021
-
Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 78:5, s. 1900-1908
-
Tidskriftsartikel (refereegranskat)abstract
- Predators often predate on a limited size range of prey, which may or may not overlap with size ranges of same prey targeted by fisheries. When they do overlap, the effect of competition over that prey is immediate, as the predator removes prey, which are at the same time suitable for the fishery. However, if the predator consumes the same prey species as the fishery, but targets smaller prey sizes, this predation on smaller sizes may result in a potential loss of future, rather than current, fishing opportunities. Comparative analyses of predator size preference and fisheries selectivity are scarce, despite their relevance in the context of integrated management of fish populations. We evaluated how size-selective cod predation influences the dynamics of sprat and herring in the Baltic Sea, as well as the competition with pelagic fisheries through immediate and delayed effects. We found a large overlap (30-60%) between prey lengths targeted by cod and fisheries, which was largest in the 1970s-1980s, when cod had higher abundance and was larger in size. Cod generally consumes herring and sprat, which are smaller than those caught by the fisheries, causing both immediate and delayed effects on prey biomass available for the fisheries.
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| 50. |
- Larsson, Stefan, et al.
(författare)
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Characteristics of anadromous whitefish (Coregonus lavaretus (L.)) rivers in the Gulf of Bothnia
- 2013
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Ingår i: BIOLOGY AND MANAGEMENT OF COREGONID FISHES - 2011. - 9783510470662 ; 64, s. 189-201
-
Konferensbidrag (refereegranskat)abstract
- In order to study anadromous whitefish spawning river requirements, we sampled 41 rivers in the Gulf of Bothnia for newly hatched whitefish larvae for one to three consecutive years. Chemical and morphological data (e.g. flow rate, topography, pH, estuary fetch and distance to coastal sandy areas) were collected for each river. Newly-hatched whitefish were caught in 19 rivers whereas whitefish were not confirmed present in 22 rivers. By applying partial least squares discriminant analysis (PLS-DA), data for rivers confirmed to support whitefish were contrasted with data for rivers in which whitefish were not found. The single most important factor was annual average water flow rate. Whitefish larvae were observed in 93% of the rivers with annual mean flow rate > 5 m(3) s(-1) (N = 14). In contrast, newly-hatched whitefish were only found in 22% of the smaller rivers (N = 27).
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