Browsing by Author "Jacobsen, Nis"
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- The second workshop on lists of commercial fish and shellfish species for reporting of MSFD D3 (WKD3Lists2)Publication . Armelloni, Enrico; Bergström, Lena; Canal, Gema; Delaunay, Damien; Foucher, Eric; Galatchi, Madalina; Gonçalves, Patrícia; Grossmann, Jenni; Hekim, Zeynep; Jacobsen, Nis; Junquera, Susana; Kreutle, Axel; Ligas, Alessandro; Maneiro, Isabel; Mirny, Zuzanna; Müller, Miriam; Nikolaus Probst, Wolfgang; Raicevich, Saša; Rowe, Owen; Saks, Lauri; Salvany, Lara; Santos, Régis; Sartor, Paolo; Scarcella, Giuseppe; Seixas, Sónia; Silva, Ualerson; Silva, Wendell; Tiganov, George; Vasilakopoulos, Paris; Walmsley, Suzannah; Wennhage, HåkanWKD3Lists2 created lists of regionally relevant commercial fish and shellfish species (and higher order taxa) for the use of Article 8 reporting by EU member states under Descriptor 3 of the Marine Strategy Framework Directive (MSFD). The regional taxa lists were based on landings data from the Fisheries Dependent Information data base (FDI) provided by EU member states and compiled by the Joint Research Centre (JRC). The taxonomy of landings data was consolidated by regional experts and the consolidated data were combined to obtain absolute and proportional landing weights and values for each (sub)re-gion, which were used to apply dual (weight and vale) selection thresholds to compile (sub)re-gional D3-taxa-lists. Regional D3-taxa-lists were produced for two MSFD regions (Baltic Sea & Black Sea) and eight MSFD subregions: The Greater North Sea, Celtic Seas, the Bay of Biscay and Iberian Coast, Mac-aronesia, Western Mediterranean, the Ionian Sea & Central Mediterranean, the Adriatic Sea and the Aegean-Levantine Sea. To exclude taxa with very low landing weights or value from the final lists, two types of thresh-olds (cumulative and minimum) with differing cut-off values were evaluated (90%, 95%, 98% and 99% for cumulative and 0.1% and 1% for minimum thresholds). Depending on the cut-off value, the number of taxa included varied substantially and in most (sub)regions the application of thresholds reduced the initial number of taxa by more than 50%. WKD3Lists2 did not recommend any threshold type or cut-off value to be applied generically in all (sub)regions, but identified trade-offs between inclusiveness and parsimony of relevant con-tent i.e. higher cut-off values will lead to longer lists including many taxa with relatively low landings weights/values. In some (sub)regions, thresholds with lower cut-off values (90% to 95%) were considered feasible by regional experts (Mediterranean subregions, Bay of Biscay and Iberian Coast, Macaronesia), whereas in other MSFD (sub)regions cut-off values in the range of 98-99% were considered as appropriate (Baltic Sea, Greater North Sea, Celtic Seas). The regional D3-taxa lists by WKD3Lists2 were created without considering the availability of data or assessments i.e. many species are included, for which no assessment information is avail-able. WKD3Lists2 decided on this approach because a representative selection of commercially targeted taxa was considered to indicate knowledge and data gaps in current data collection and assessment schemes. Regional species lists shall be used by EU member states for the national reporting of D3. Stocks and species from the regional lists shall be considered by member states, and additional stocks/species can be added where appropriate (e.g. those stocks/species of national or local of importance that do not appear on the regional lists). x WKD3Lists2 discussed and compiled recommendations on how Member States can complement the regional lists of D3-taxa. A key recommendation is to maintain taxa reported in 2018 under D3, even if they are not part of the regional D3-taxa list for 2024. Wherever possible, Member States should report on stock level. WKD3Lists2 also discussed linkages between D1 and D3-reporting of commercial taxa.
- Workshop to apply thresholds for the preselected indicators for MSFD D3C3 (WKD3C3THRESHOLDS)Publication . Rindorf, Anna; Scarcella, Giuseppe; Armelloni, Enrico; Bartolino, Valerio; Bellido, Jose; Bolund, Elisabeth; Boulcott, Phillip; Campon-Linares, Victoria; Canal, Gema; Caserman, Helena; Coscia, Ilaria; Fortibuoni, Tomaso; Garnacho, Eva; Giujarro, Beatriz; Gonçalves, Patricia; Griffiths, Chris; Jacobsen, Nis; Kuehn, Bernhard; Maneiro, Isabel; Silva, Ualerson; Probst, Nikolaus; Rowe, Owen; Seixas, Sónia; Tifoura, Amina; Vasilakopoulos, Paris; Villanueva, Ching; Wennhage, Håkan; Zaragoza, NuriaThe WKD3C3THRESHOLDS meeting provided a platform for experts from the EU member states to meet and progress the assessment methodology on Criteria 3 of Descriptor 3 upon request by EC (DGENV). WKD3C3THRESHOLDS is the second of a series of three workshops (WKD3C3SCOPE, WKD3C3THRESHOLDS and WKD3SIMUL) to identify operational indicators for MSFD D3C3. The workshop was organised as a series of presentations of results with intermittent group discussions. The D3C3 indicators agreed at WKD3C3SCOPE were estimated and documented for a selection of stocks representing different life-histories (Tor a). Plots comparing indicators were investigated for stocks with all estimated indicators. The age structure indicators ABI, ASA, POS and SSB/R generally followed the temporal development of SSB and react similarly to F. A gap of up to 10 years was observed between changes in F and subsequent changes in age structure indicators for long-lived species while SSB responded quickly to changes in F. For medium-lived stocks, the four age structure indicators exhibited similar temporal patterns, with SSB divided by R tending to be more variable. Recruitment and mean weight at age documented shifts in productivity, impacting age structure indicators differently when changes occur. Plots of F, recruitment, weight at age and SSB are considered useful for understanding cases where changes in F do not impact SSB as expected (e.g. rebuilding does not occur or stock remains high in spite of high F). Higher proportions of older fish as measured by ABI/ASA/POS or SSB/R did not appear linked to an immediate increase recruitment. A comparison of length-based and age-based indicators for Mediterranean stocks was also conducted. Recruitment detection from survey time series showed uneven patterns over stocks and time series, and in some cases depended on survey timing. Length-based indicators exhibited weak consistency information from stock assessments, and confounding effects of biological variability and sampling timing on observed recruitment pulses were noted. The indicator L90R, calculated from the length-frequency distribution of fish larger than recruiting length, seemed to perform well among those inspected. Thresholds for the D3C3 indicators for stocks representing different life-histories, data availability and MSFD (sub)regions (when possible) were discussed (ToR b and c). The suggested thresholds covered all approaches identified by WKD3C3SCOPE. Clear thresholds where the indicator signifies stock productivity declines could not be identified from the data as none of the age structure indicators showed a positive correlation with stock productivity. As a result, threshold levels cannot be determined based on levels at which stock productivity is either impaired or enhanced. In the absence of clear relationships between the indicators and stock health, the workshop used varying percentages (10th percentile, median/50th percentile) of the simulated or observed distributions of indicators to determine good status of the indicator. The analyses presented emphasized the direct influence of recruitment and growth on fisheries yield and precautionary fishing mortality limits. Finally, a decision tree to choose a threshold setting method was proposed for further testing in WKSIMULD3 on the basis of listed pros and cons discussed by WKD3C3THRESHOLD participants. The SSB/R indicator responded to recruitment in an undesirable manner but there was insufficient evidence to determine which of the three remaining age structure indicators provided a higher signal to noise due to recruitment variability. Selectivity indicators under D3C3 were retained despite unclear guidance in the MSFD guidance document. The retained indicators for medium-lived stocks with age-based assessment data include ABI, POS, ASA, R, ASW, and Fjuv/Fapical. The value of age structure indicators as management indicators was unclear for short-lived and long-lived species. For short-lived species, no strong link was found between age-structure indicators and F or SSB, and high age at spawning may lead to senescence rather than increased viability of spawning products. For long-lived species, age structure indicators appeared to react substantially later than F and SSB, making their added value for management unclear. The definition of thresholds for these indicators will be further investigated in WKSIMULD3. The assessment of stock health under D3C3 relies on crucial data such as recruitment, weight at age, and size/age distribution (ToR d). In the absence of this information, D3C3 assessments cannot be conducted, and Member States were encouraged to enhance data collection efforts. For stocks with age-based assessments, these data are considered essential input and/or output for the assessment, and assessments based on age data are preferred over those based solely on length distributions for the estimation of age structure indicators. Finally, the group drafted a list of actions to be completed for the reparation of WKSIMULD3.
- Workshop to compare the indicators for CFP and MSFD D3 management objectives through simulations (WKSIMULD3)Publication . Armelloni, Enrico; Bartolino, Valerio; Bellido, Jose; Bolund, Elisabeth; Fortibuoni, Tomaso; Garnacho, Eva; Gonçalves, Patracia; Griffiths, Chris; Howell, Daniel; Jacobsen, Nis; Junquera, Susana; Kidd, Peter; Kuehn, Bernhard; Moro, Stefano; Murphy, Natasha; Probst, Nikolaus; Rindorf, Anna; Rowe, Owen; Scarcella, Giuseppe; Seixas, Sónia; Tengvall, Jessica; Tifoura, Amina; Villanueva, Ching; Wennhage, Håkan; Woronoff, Josephine; Zaragoza, Nuria; Zolubas, Tomas; Zorica, BarbaraThe WKSIMULD3 meeting provided a platform for experts from the EU member states to meet and progress the assessment methodology on Criteria 3 of Descriptor 3 upon request by EC (DGENV). WKSIMULD3 is the third of a series of three workshops (WKD3C3SCOPE and WKD3C3THRESHOLDS being the first two) to identify operational indicators for MSFD D3C3. The workshop was organised as a series of presentations with intermittent discussions. The group agreed on a number of stocks to run simulations to explore the relationships between indicators of population traits/dynamics and healthy population structure. The participants found that for demersal stocks in the North Sea, MSE simulations showed decreasing values of D3C3 indicators with increasing fishing mortality. However, the use of age-structure indicators for these stocks is likely to lead to frequent false positives due to the high interannual variability. Age-based simulations were implemented also for pelagic and short-lived stocks, such as mackerel, sprat, and sandeel. The distribution of the threshold values implemented for the stocks did not show a clear response to the fishing regime. As a result, the use of age-structure indicators for these stocks is likely to lead to frequent false positives/negatives. The simulations aimed to validate the population size structure and calculate indicators under different fishing scenarios. In the Mediterranean Sea, length-based simulations were conducted for two hake stocks and one sole stock. The length indicators obtained were compared to historical data to assess the responsiveness of the indicators to exploitation. These results show the behaviour of the length based and of the age-based indicators calculated on observed data. Overall, the indicator status can be well below the average value at Fmsy. Additionally, an exploratory run tested a harvest control rule driven by age-based indicator targets. The outputs can provide directions on how to choose a threshold that can ensure the stock to be in GES. Overall, the workshop findings highlighted the complexity of evaluating indicators for CFP and MSFD D3 management objectives, particularly in relation to the responsiveness of the indicators to fishing pressure and environmental variation. The group emphasized the need for robust and peer-reviewed models to ensure reliable results when evaluating indicators for fish stocks. Additionally, it underscores the challenges associated with using age- and length-based indicators for different species and the importance of considering environmental and recruitment variability in simulations. In conclusion, the series of the 3 workshops contributed valuable insights into the complexities of assessing and comparing indicators for MSFD D3 management objectives, providing important considerations for future assessments and management strategies.