| 1. |
- Adill, Anders, et al.
(author)
-
Effekthöjningsprogrammet vid Forsmarks kärnkraftverk : Sammanfattande rapport från de tre första årens undersökningar
- 2014
-
Reports (other academic/artistic)abstract
- Miljödomstolens deldom 2008-08-21 i målen M 1666-07/M 5786-07 lämnade Forsmark Kraftgrupp AB (FKA) tillstånd att enligt miljöbalken höja den termiska effekten vid kärnkraftverket från 9156 MW till 10281 MW. När effekthöjningen är slutförd beräknas kylvattenflödet ha ökat med cirka 20 procent till 170 kubikmeter per sekund för samtliga tre anläggningar och utsläppstemperaturen i Biotestsjön förväntas ha höjts från 10,3°C till 11,0°C. I samband med effekthöjningarna i kärnkraftverket förväntas den fysiska vattenmiljön och dess organismer påverkas främst genom ökat kylvattenflöde och därmed ytterligare höjda vattentemperaturer i närrecipienten. Enligt prövotidsförordnanden i domen ska det avgöras vilken betydelse den ökade vattenbortledningen av kylvatten och den ökade värmetillförseln till havet kan få för det allmänna fiskeintresset. FKA ska i samråd med Fiskeriverket (numera SLU, institutionen för akvatiska resurser), som är tillförordnad sakkunnig i utredningen, undersöka påverkan på fisket av den ökade vattenbortledningen och den ökade värmetillförseln enligt program (effekthöjningsprogrammet) som Fiskeriverket och FKA kom överens om. Resultatet av utförda undersökningar och utredningar med förslag till slutligt avgörande av frågorna ska redovisas till miljödomstolen senast fem år från det att effekthöjningarna tagits i drift. Denna rapport redovisar resultaten och kunskapsunderlaget från undersökningarna inom den första delen av effekthöjningsprogrammet under åren 2009-2014 samt ger en generell beskrivning av utvecklingen för delar av fisksamhället i Forsmarksområdet. Delmoment inom effekthöjningspro-grammet som avser effekter av ökat vattenflöde består av studier för fiskrekrytering av varmvattenarter i intagsområdet för kylvatten, fiskförluster i silstationerna på kraftverket samt effekter på uttransport av yngel från Biotestsjön. Moment som avser effekterna av ökad vattentemperatur i recipienten är ålders- och tillväxtstudier hos abborre, förekomst och överlevnad av sikyngel i plymområdet, samt anlockning av strömming och romöverlevnad i utsläppsområdet. Den första delen av undersökningarna genomförs innan det ökade energiuttaget inletts på kraftverket. När kärnkraftverket färdigställt utbyggnaden och produktionen uppnått den nya effektnivån ska undersökningarna inom effekthöjningsprogrammet upprepas under tre år. I slutrapporteringen av effekthöjningsprogrammet ska resultaten av utförda undersökningar och utredningar presenteras till miljödomstolen med slutligt utlåtande om effekterna för det allmänna fiskeintresset av den ökade vattenbortledningen av kylvatten och ökade värmetillförseln till havet. Resultaten från första delen av effekthöjningsprogrammet visar att tätheterna av abborre, gädda och mört är mycket låga i intagsområdet i Asphällafjärden. Förlusterna av fisk i silstationerna i kärnkraftverket är omfattande. De största mängderna fastnar under vårarna och senhöstarna, vilket sammanfaller med när den ordinarie provtagningen inom baskontrollprogrammet äger rum. Storspigg i provtagningarna utgör nästan 80 procent av rensmassorna till antalet. Tillväxten hos abborre under första levnadsåret är snabb för individer i Biotestsjön jämfört med abborrar i Forsmarks skärgård och Finbofjärden. I Forsmarksområdet har tillväxten hos årsyngel av abborre ökat sedan mitten av 1990-talet och har uppnått likadana tillväxthastigheter som hos abborrar från Biotestsjön. Denna utveckling finns inte hos abborrar i referensområdet Finbofjärden på Åland. I utsläppsområdet från Biotestsjön finns det en påvisad anlockning av strömming under vårperioden i samband med lek. Lekaktiviteten hos strömming är större inom effektområdet med uppvärmt vatten än på platser som inte påverkas av en temperaturökning. Förekomsten av sikyngel i utsläppsområdet är extremt låg, vilket sannolikt är en följd av den generella utvecklingen för arten i Bottenhavet. För att slutrapporteringen till miljödomstolen med slutligt avgörande i frågorna ska vara av erforderlig kvalité är det nödvändigt att kompletterande studier genomförs för att få tillräckligt med underlag. För att utröna den geografiska omfattningen av effekter av kylvattenutsläppet på strömming är det nödvändigt att utöver de redan planerade ekointegreringarna i kylvattenplymen komplettera med undersökningar i hela Öregrundsgrepen. Larv- och yngelundersökningar borde genomföras vid kylvattenintagen till kraftverket för att uppskatta förlusterna av fisk i dessa livsstadier. Dessutom bör det undersökas hur omfattande lekaktiviteten är för abborre och gädda i Asphällafjärden.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Bergenius, Mikaela, et al.
(author)
-
Fishing or the environment - what regulates recruitment of an exploited marginal vendace (Coregonus albula (L.)) population?
- 2013
-
In: Advances in Limnology. - 1612-166X. ; 64, s. 57-70
-
Conference paper (peer-reviewed)abstract
- Fish populations inhabiting marginal areas are generally highly susceptible to environmental variation and therefore show large fluctuations in recruitment. The commercially important, and usually freshwater, vendace (Coregonus albula (L.)) occupying the brackish waters of the Bothnian Bay forms one such marginal population and shows large annual variation in recruitment. Here, we investigate the relative importance of fishing (trawling time), hydro-climatic factors and species interactions in explaining the variability in vendace recruitment using three sets of models. A comparison of the best models in the hydro-climatic model set and the fishing model revealed that the hydro-climatic variables were overall superior to the anthropogenic model in describing recruitment variability. Trawling time and water temperature in winter combined with salinity explained 33 and 63.7% of the variation in recruitment, respectively. The importance of water temperature and salinity, in combination with the effects of trawling time, calls for catch levels to be set with caution in this vendace fishery.
|
|
| 5. |
- Bergenius, Mikaela, et al.
(author)
-
Report of the Baltic Fisheries Assessment Working Group (WGBFAS) : 14-21 April 2015, ICES HQ, Copenhagen, Denmark
- 2015
-
Reports (other academic/artistic)abstract
- The ICES Baltic Fisheries Assessment Working Group (WGBFAS) met 14-21 April 2015 (Chair: Mare Storr-Paulsen, Denmark), with 28 participants and 9 countries represented. The objective of WGBFAS was to assess the status of the following stocks:1 ) Sole in Division IIIa, SDs 20-222 ) Cod in Kattegat, Cod in SD 22-24, Cod in SD 25-323 ) Herring in SD 25-27, 28.2, 29 and 32, Herring in SD 28.1 (Gulf of Riga), Herring in SD 30, Herring SD 31.4 ) Sprat in SD 22-325 ) Plaice 21-23, Plaice 24256 ) Flounder 22-23; 24-25; 26+28 and 27+29-32, Brill 2232, Dab 2232, and Turbot 2232 (survey trends)WGBFAS also identified the data needed, for next year’s data call with some suggestions for improvements in the data call as well as in InterCatch. The report contains an introduction with the summary of other WGs relevant for the WGBFAS, country specific fishery description, the methods used, and ecosystem considerations. The results of the analytical stock assessment or survey trends for the species listed above are then presented with all the stocks with the same species in the same sections. The report ends with references, list of Working Documents, recommendations and Stock Annexes. In first quarter 2015 the Baltic cod stocks and the plaice stocks were benchmarked. As a result the Baltic cod stocks now have to apply a splitting key in SD 24 were both stocks are present. This has changed the assessment from being an area based assessment to now being a stock based assessments and has implications for the advice. The principle analytical models used for the stock assessments were XSA and SAM. For most flatfishes, CPUE trends from bottom trawl surveys were presented (except plaice 2425 and her31 using relative SSB from SAM and XSA, respectively). Ecosystem changes have been analytically considered in the following stock assessments: Herring in SD 25-27, 28.2, 29 and 32, and Sprat in SD 22-32, in form of cod predation mortality. Last year a very large retrospective pattern in the Eastern Baltic cod stock caused that the WG rejected the analytic assessment. Several uncertainties in the data lead to this conclusion i.a age reading problems with large inconsistency between and within nations as well as a change in growth and natural mortality. However, even though a data compilation workshop and a benchmark have been conducted in the intermediate time it was not possible to solve the main issue on growth. The lack of knowledge on growth caused to that even the length based data required in the data call was very uncertain for the models and in the end the WG was not able to produce a better model than was presented last year which is based on survey trends. The Her-30 (Herring in the Botnian Sea) was by the working group down scaled from a category 1 stock to a category 3 stock due to the commercial tuning fleet used in the assessment having very uncertain estimates in the last couples of years. However, during the Baltic ADG an alternative assessment was suggested were the stock is still considered a category 1 stock but the last 8 years of the commercial tuning fleet was terminated. This assessment was conducted after the working group but has been included in the report.
|
|
| 6. |
|
|
| 7. |
- Bryhn, Andreas, et al.
(author)
-
Fisk- och skaldjursbestånd i hav och sötvatten 2020 : Resursöversikt
- 2021
-
Reports (other academic/artistic)abstract
- I rapporten kan du ta del av bedömningen som görs av situationen för bestånd som regleras inom ramen för EU:s gemensamma fiskeripolitik (GFP). Bedömningarna baseras på det forskningssamarbete och den rådgivning som sker inom det Internationella Havsforskningsrådet (ICES). Totalt redovisas underlag och råd för 48 fisk- och skaldjursarter.De bestånd som förvaltas nationellt baseras på de biologiska underlagen, och rådgivningen i huvudsak på den forskning och övervakning samt analys som bedrivs av Institutionen för akvatiska resurser vid Sveriges lantbruksuniversitet (SLU Aqua) samt yrkesfiskets rapportering.
|
|
| 8. |
|
|
| 9. |
- Cardinale, Massimiliano, et al.
(author)
-
Benchmark workshop on herring (Clupea harengus) in the Gulf of Bothnia (WKCLuB 2021)
- 2021
-
Reports (other academic/artistic)abstract
- The assessment for the Gulf of Bothnia herring (SD 3031) in 2019 was not accepted by the Advice Drafting Group and was changed from category 1 to 3. The assessment was not accepted based on the poor retrospective diagnostics where the Mohn’s rho values were above 20% for SSB, F and recruitment. The aim for the Benchmark was to evaluate a new model, Stock Synthesis (SS3) as a candidate for the assessment of Gulf of Bothnia Herring SD30–31 in order to minimize the retrospective pattern previously observed. Following the path of the Benchmark data related issues were revealed. This led to a situation that the benchmark was prolonged one year in order to correct the data related issues. Apart from a misspecification in the model about how the trapnet index was used (abundance index vs. biomass index), the data problem had been related to the acoustic survey. The acoustic survey index used in the assessment was thoroughly examined by the Baltic international fish survey working group (WGBIFS) in a meeting in December 2020. A number of model runs (six prior to meeting, and an additional 16 during the benchmark) were conducted for evaluation at this benchmark. The analysis presented extensive diagnostic tests including the standard ICES criterion related to retrospective patterns. This was considered an enhancement over using one method for accepting or rejecting an assessment. It was noted that the final retrospective pattern had low and acceptable values of Mohn’s rho. In general, the benchmark using the stock synthesis platform with the settings specified during the benchmark are considered acceptable for assessment and advice and have features that should ensure stability as new data are added (e.g. selectivity is assumed to be constant over time).
|
|
| 10. |
- Carlos, Diaz-Gil, et al.
(author)
-
Spatio-temporal composition and dynamics of zooplankton in the Kalmar Sound (western Baltic Sea) in 2009-2010
- 2014
-
In: Boreal Environment Research. - 1239-6095 .- 1797-2469. ; 19:4, s. 323-335
-
Journal article (peer-reviewed)abstract
- In pelagic food webs, zooplankton is the link between lower and higher trophic levels. It is thus essential to know how the zooplankton community structure varies with its environment. We investigated the seasonal and spatial variation in the zooplankton diversity and community structure during two consecutive years in the Kalmar Sound, along the Swedish east coast, an area with a strong bathymetric gradient and of high ecological importance for e.g. commercial fish species. Two zooplankton communities were identified in the area: a coastal/estuarine community in the south and an open-water community in the north. They were separated mainly by differing salinity and temperature conditions. Biodiversity increased from spring to autumn and was higher in the open waters.
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
|
|
| 16. |
|
|
| 17. |
|
|
| 18. |
|
|
| 19. |
- Kaljuste, Olavi
(author)
-
Management of the Gulf of Riga herring (Baltic Sea): Lessons learned and challenges ahead
- 2023
-
Conference paper (peer-reviewed)abstract
- Maximum sustainable yields and maintaining the intraspecific biodiversity are the aim in fish stock management. Here populations-based management would be the preferred practice. Yet available stock discrimination methods result in establishing the conventional assessment/management units as a compromise. The Baltic herring (Clupea harengus membras L.) exhibits remarkable geographical variabil-ity, forming up to12 local populations. Due to reasons mentioned above, only two distinct local populations (Gulf of Riga, (GoR) herring and Gulf of Bothnia herring), are treated as separate assessment and manage¬ment units. The paper describes the annual workflow of the management process, collection of the biological information from commercial catches and from the research surveys. Management history of GoR herring has revealed a number of challenges. Acoustic estimates are the only fisheries-independent data applied in GoR herring stock assessment. The study highlights the need for methodological changes what are expected to allow enhancing the quality of stock estimates, serving as the basis for the management decisions. We show that while before climate-driven regime shift (prior-1990s) recruitment was determined by the winter tem¬perature, affecting survival of Young of the year, a new major productivity bottleneck is in increasing spring-summer water temperatures during hatching and larval first-feeding stage.
|
|
| 20. |
- Kaljuste, Olavi
(author)
-
Managing the spatial and temporal pattern of Baltic herring trawl fishery: A potential tool for sustainable resource management?
- 2014
-
Conference paper (peer-reviewed)abstract
- Herring, Clupea harengus is traditionally one of the main targets of the Baltic Sea commercial fishery. The bulk of catches (100,000 to 230,000 t in the last two decades), is taken from the Central Baltic Herring stock (CBH), showing a decreasing trend throughout the most of its management history. The CBH fishery is internationally managed on the basis of annual Total Allowable Catch (TAC) and a few technical measures. The excessive fisheries mortality, exceeding F-MSY, however, has been the major obstacle in management, not allowing reversing the declining stock trend and bringing it back to the safe biological limits. The CBH includes a number of local populations with different morphometric characteristics and growth rate. This paper is focusing on spatial aspects of herring fishery (effort allocation) in the North-eastern Baltic Sea where 40-60% of total CBH catch is taken. The results allow concluding that due to the spatial diversity in size/weight structure of herring, the fishing mortality in local stocks can significantly differ from values estimated for the combined stock. Consequently, consideration of spatial heterogeneity of stocks in fisheries management process can be an efficient tool for control of fishing mortality and stock protection.
|
|
| 21. |
- Kaljuste, Olavi
(author)
-
Reducing uncertainties in Baltic herring and sprat abundance estimates: Alternative approach to acoustic analyses
- 2021
-
In: Proceedings in Marine Technology and Ocean Engineering. - London : CRC Press. - 2638-647X. ; 6, s. 721-727
-
Conference paper (peer-reviewed)abstract
- Hydroacoustic studies using acoustic measurements combined with biological data obtained from trawl hauls remain a challenging task. The main purpose of the present study is to identify sources of uncertainty and compare the calculation methods for a mixed pelagic fish community of Baltic Sea. Most of the calculation methodologies use conventional statistical borders to split the study area, ignoring the possible natural population distribution areas. We compared the proposed “nearest haul” and the “subdivision average” with the conventional “rectangle average” on the Estonian regular acoustic surveys in the northeast Baltic Sea. The abundance estimates of the target species – European sprat Sprattus sprattus (Linnaeus 1758) and Baltic herring Clupea harengus membras (Linnaeus 1758) – with the “nearest haul” were significantly different from the currently used method, which indicates a strong effect of the allocation method. Our results indicate a need for a large scale comparative study to consider alternative calculation methodologies.
|
|
| 22. |
|
|
| 23. |
|
|
| 24. |
|
|
| 25. |
|
|
| 26. |
|
|
| 27. |
|
|
| 28. |
|
|
| 29. |
|
|
| 30. |
|
|
| 31. |
|
|
| 32. |
|
|
| 33. |
- Ljunggren, Lars, et al.
(author)
-
Recruitment failure of coastal predatory fish in the Baltic Sea coincident with an offshore ecosystem regime shift
- 2010
-
In: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 67:8, s. 1587-1595
-
Journal article (peer-reviewed)abstract
- The dominant coastal predatory fish in the southwestern Baltic Sea, perch and pike, have decreased markedly in abundance during the past decade. An investigation into their recruitment at 135 coastal sites showed that both species suffered from recruitment failures, mainly in open coastal areas. A detailed study of 15 sites showed that areas with recruitment problems were also notable for mortality of early-stage larvae at the onset of exogenous food-intake. At those sites, zooplankton abundance predicted 83 and 34% of the variation in young of the year perch and pike, respectively, suggesting that the declines were caused by recruitment failure attributable to zooplankton food limitation. Incidences of recruitment failure match in time an offshore trophic cascade that generated massive increases in planktivorous sprat and decreases in zooplankton biomass in the early 1990s. Therefore, sprat biomass explained 53% of the variation in perch recruitment from 1994 to 2007 at an open coastal site, where three-spined stickleback also increased exponentially after 2002. The results indicate that the dramatic change in the offshore ecosystem may have propagated to the coast causing declines of the dominating coastal predators perch and pike followed by an increase in the abundance of small-bodied fish.
|
|
| 34. |
- López, María-Eugenia, et al.
(author)
-
Lack of panmixia of Bothnian Bay vendace-Implications for fisheries management
- 2022
-
In: Frontiers in marine science. - : Frontiers Media SA. - 2296-7745. ; 9
-
Journal article (peer-reviewed)abstract
- Overexploitation of fisheries is recognized as a major environmental and socioeconomic problem that threats biodiversity and ecosystem functioning. Inappropriate management policies of fish stocks have been applied as a consequence of inadequate characterization of subtle genetic structure in many fish species. In this study, we aim to assess the extent of genetic differentiation and structure of vendace (Coregonus albula) collected from eight locations in the Bothnian Bay, the northernmost part of the Baltic Sea. Specifically, we test if this species forms a single panmictic population or is divided into several genetically distinct units. We used restriction site-associated DNA sequencing (RAD-seq) to identify 21,792 SNPs based on 266 individuals. We identified a clear pattern of genetic differentiation between River Kalix and the other sampling locations, and a weak structuring between samples from Swedish and Finnish coast. Outlier analysis detected 41 SNPs putatively under divergent selection, mainly reflecting the divergence between River Kalix and the other samples. The outlier SNPs were located within or near 25 genes, including voltage-dependent calcium channel subunit alpha-2 (CACNA2D2), cadherin 26 (CDH26) and carbonic anhydrase 4-like (CA4) that have earlier been associated with salt-tolerance and salinity stress. Our study provides the first genome-wide perspective on genetic structuring of Baltic Sea vendace and rejects the hypothesis of panmixia in the Bothnian Bay. As such, our work demonstrates the power of RAD-sequencing to detect low but significant genetic structuring relevant for fisheries management.
|
|
| 35. |
|
|
| 36. |
- Olin, Agnes B., et al.
(author)
-
Increases of opportunistic species in response to ecosystem change : the case of the Baltic Sea three-spined stickleback
- 2022
-
In: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 79:5, s. 1419-1434
-
Research review (peer-reviewed)abstract
- Under rapid environmental change, opportunistic species may exhibit dramatic increases in response to the altered conditions, and can in turn have large impacts on the ecosystem. One such species is the three-spined stickleback (Gasterosteus aculeatus), which has shown substantial increases in several aquatic systems in recent decades. Here, we review the population development of the stickleback in the Baltic Sea, a large brackish water ecosystem subject to rapid environmental change. Current evidence points to predatory release being the central driver of the population increases observed in some areas, while both eutrophication and climate change have likely contributed to creating more favourable conditions for the stickleback. The increasing stickleback densities have had profound effects on coastal ecosystem function by impairing the recruitment of piscivorous fish and enhancing the effects of eutrophication through promoting the production of filamentous algae. The increase poses a challenge for both environmental management and fisheries, where a substantial interest from the pelagic fisheries fleet in exploiting the species calls for urgent attention. While significant knowledge gaps remain, we suggest that the case of the Baltic Sea stickleback increase provides generalisable lessons of value for understanding and managing other coastal ecosystems under rapid change.
|
|
| 37. |
- Olsson, Jens, et al.
(author)
-
The first large-scale assessment of three-spined stickleback (Gasterosteus aculeatus) biomass and spatial distribution in the Baltic Sea
- 2019
-
In: ICES Journal of Marine Science. - : Oxford University Press. - 1054-3139 .- 1095-9289. ; 76:6, s. 1653-1665
-
Journal article (peer-reviewed)abstract
- Declines in predatory fish in combination with the impact of climate change and eutrophication have caused planktivores, including three-spined stickleback (Gasterosteus aculeatus), to increase dramatically in parts of the Baltic Sea. Resulting impacts of stickleback on coastal and offshore foodwebs have been observed, highlighting the need for increased knowledge on its population characteristics. In this article, we quantify abundance, biomass, size structure, and spatial distribution of stickleback using data from the Swedish and Finnish parts of the Baltic International Acoustic Survey (BIAS) during 2001-2014. Two alternative methods for biomass estimation suggest an increase in biomass of stickleback in the Baltic Proper, stable or increasing mean size over time, and larger individuals toward the north. The highest abundance was found in the central parts of the Baltic Proper and Bothnian Sea. The proportion of stickleback biomass in the total planktivore biomass increased from 4 to 10% in the Baltic Proper and averaged 6% of the total planktivore biomass in the Bothnian Sea. In some years, however, stickleback biomass has ranged from half to almost twice that of sprat (Sprattus sprattus) in both basins. Given the recent population expansion of stickleback and its potential role in the ecosystem, we recommend that stickleback should be considered in future monitoring programmes and in fisheries and environmental management of the Baltic Sea.
|
|
| 38. |
- Orio, Alessandro, et al.
(author)
-
Report of the Baltic Fisheries Assessment Working Group (WGBFAS) : 19-26 April 2017, Copenhagen, Denmark
- 2017
-
Reports (other academic/artistic)abstract
- The ICES Baltic Fisheries Assessment Working Group (WGBFAS) met 19-26 April 2017(Chair: Tomas Gröhsler, Germany and Co-chair: Michele Casini, Sweden), with 41 participants and 9 countries represented. The objective of WGBFAS was to assess the status of the following stocks: Sole in Division 3.a, SDs 20–24; Cod in Kattegat, Cod in SDs 22–24, Cod in SDs 25–32; Herring in SDs 25–27, 28.2, 29 and 32, Herring in SD 28.1 (Gulf of Riga), Herring in SDs 30-31 (Gulf of Bothnia); Sprat in SDs 22–32; Plaice in SDs 21–23, Plaice in SDs 24–25; Flounder in SDs 22–23, in SDs 24–25, in SDs 26+28 and SDs 27+29–32; Brill in SDs 22–32, Dab in SDs 22–32 and Turbot in SDs 22–32. WGBFAS also identified the data needed for next year’s data call with some suggestions for improvements in the data call, and stock-specific research needs.The report contains an introduction with the summary of other WGs relevant for the WGBFAS, the methods used, and ecosystem considerations. The results of the analytical stock assessment or survey trends for the species listed above are then presented with all the stocks with the same species in the same sections. The report ends with references, recommendations, links to Stock Annexes and list of Working Documents.The principle analytical models used for the stock assessments were XSA and SAM. For most flatfishes and cod in SDs 25–32 (data limited stocks), CPUE trends from bottomtrawl surveys were used in the assessment (except plaice in SDs 24–25 for which relative SSB from SAM was used). For the data limited stocks, reference points based on length-based indicators were estimated (except cod in SDs 25-32 for which relative reference points were estimated using the SPiCT model). For cod in SDs 25–32, intersessional work was planned to hopefully allow returning to an analytical stock assessment in the near future. Ecosystem changes have been analytically considered in the following stock assessments: Herring in SD 25–27, 28.2, 29 and 32, and Sprat in SD 22–32, in form of cod predation mortality.
|
|
| 39. |
|
|
| 40. |
|
|
| 41. |
|
|
| 42. |
- Sundelöf, Andreas, et al.
(author)
-
Fisk- och skaldjursbestånd i hav och sötvatten 2021 : Resursöversikt
- 2022
-
Reports (other academic/artistic)abstract
- I rapporten kan du ta del av bedömningen som görs av situationen för bestånd som regleras inom ramen för EU:s gemensamma fiskeripolitik (GFP). Bedömningarna baseras på det forskningssamarbete och den rådgivning som sker inom det Internationella Havsforskningsrådet (ICES). Sammantaget redovisas tillståndet för 107 bestånd av 48 fisk- och skaldjursarter.De bestånd som förvaltas nationellt baseras på de biologiska underlagen, och rådgivningen i huvudsak på den forskning och övervakning samt analys som bedrivs av Institutionen för akvatiska resurser vid Sveriges lantbruksuniversitet (SLU Aqua) samt yrkesfiskets rapportering.Rapporten är en beställning från Havs- och vattenmyndigheten (HaV) till Sveriges lantbruksuniversitet (SLU) och utgör ett viktigt kunskapsunderlag till myndighetens arbete. Den uppfyller de krav som finns inom EU:s gemensamma fiskeripolitik om att basera förvaltningen på bästa tillgängliga vetenskap. Denna rapport är också ett stöd till det arbete som beskrivs närmare i strategin för framtidens fiske och tillhörande handlingsplaner för vattenbruk, yrkes- och fritidsfiske som HaV och Jordbruksverket har tagit fram i dialog med fiskets och vattenbrukets intressenter.
|
|
| 43. |
|
|
| 44. |
- Östman, Örjan, et al.
(author)
-
Relative contributions of evolutionary and ecological dynamics to body size and life-history changes of herring (Clupea harengus) in the Bothnian Sea
- 2014
-
In: Evolutionary Ecology Research. - 1522-0613. ; 16, s. 417-433
-
Journal article (peer-reviewed)abstract
- Question: What ecological and evolutionary processes are associated with the 25% decrease in age-specific body size of herring (Clupea harengus) in the Bothnian Sea over the last 30 years?Data: Four decades of data on length, age, and sexual maturity of individual herrings as well as environmental variables, including abundances of predators, prey and competitors, and estimates of fishing intensity/mortality from the Bothnian Sea.Search methods: Information-theoretic assessment of the relative influence of ecological and fisheries' effects on temporal changes in body growth. Probabilistic maturation reaction norms to study changes in age-specific size at maturation. Decomposition of trait variation into ecological and evolutionary contributions.Conclusions: Our evolutionary ecosystem perspective shows that both ecological and evolutionary processes are important contributors to observed phenotypic changes in this commercially exploited species. Around 60% of the decrease in age-specific body length can be attributed to increased density-dependent body growth. Evolutionary changes towards earlier maturation, owing to an indirect effect of size-selective mortality from grey seals and fisheries, account for a further 25% of the decrease in age-specific body size.
|
|
