The 2019 report of the Balance Expert Working Group, STECF-19-13, paid particular attention to the discrepancy in indicators values between the national fleet reports and their own calculations for the year 2017. They observed that the Netherlands used a different fleet segmentation, thereby making comparisons difficult. Furthermore, they found large differences in the two biological indicators and some small differences in the economic indicators, which in some cases even indicated a different state of balance compared to what the Dutch national fleet report concluded. This report therefore investigated the discrepancy in balance indicator values from 2017, with the aim to explain the observed differences and to re-calculate the indicators for the national fleet report for the 2017 data with the same fleet segmentation and methods as STECF-19-13. For the biological indicators, differences in indicator values were caused by a wrong interpretation in the Dutch national fleet report of the equations in the 2014 Commission guidelines. Furthermore, not all stocks that were fished upon by fleet segments were included in the analysis of the fleet report, thereby excluding stocks that were still overexploited. Different procedures on how to divide the landings data by species over the stocks may also have led to the discrepancy in biological indicators. Differences in the economic indicators were small compared to the biological indicators, and both the fleet report and STECF-19-13 came to the same conclusions regarding the balance of the fleet from an economic point of view. The small discrepancies were caused using different interest rates and real values. No difference in technical indicators was observed for the pelagic fleet segment. Redoing the calculations for the national fleet report with the 2017 data and the same fleet segmentation as STECF led to the same or very similar values for most indicators. Future work is needed in close cooperation with the Balance EWG to make sure that the methods are aligned with both the Commission guidelines and STECF. This is particularly applies to the biological indicators, for which some small differences with the STECF values were still observed after improving the methods. Based on the findings in this report, it is recommended to become more actively involved in the Balance EWG, preferably by having somebody with biological expertise attending future EWG meetings who can solve the remaining issues in the national fleet report calculations and avoid any discrepancies in the future. Furthermore, the biological section of the national fleet report should include time series of the biological indicators, as management measures may take time before the desired state and balance are reached. Future fleet reports should also use a landings data splitting procedure tailored to the year of interest and to the Dutch landings. Regarding the economic and technical indicators, it is recommended to use both the STECF fleet segmentation (to allow for comparison with the EWG) and the clustered segmentation to ensure that local knowledge and context of the fleet is provided, as the data of particularly the small-scale fleet segment, and therefore also its indicators, need to be interpreted with caution.

The stock assessment of plaice in IIIa has been long known as producing problems. The fluctuation of fishing mortality estimates has led to the rejection of the assessment by the working group for two years. The main changes in input data are presented in this report (catch data, biological data and commercial tuning series). Catches in 22 area (Belt Sea) have been added to the IIIa catches because there is strong belief that plaice in this area is actually part of the IIIa stock. Several subsets of tuning fleets have been extracted and new ways of effort standardisation have been implemented. New maturity ogives and mean weights at age in stock have been calculated from survey data. The different scenarios have then been compared trough XSA using FLR, and their performance has been evaluated via a set of synthetic and objective indices. Main results are that assessments perform better with kW fishing days as effort measurement and the Belt Sea should be included in the stock assessment of IIIa plaice.

The exemptions under the landing obligation (LO) for undersized plaice and sole in the 80 mm beam trawl fishery expire in 2023. The European Commission has indicated that new scientific substantiation is needed to maintain the exemption. Here we evaluate the conservation strategies of adjusting the minimum conservation reference size ("MCRS”, currently 27 cm for plaice and 24 cm for sole) to 25 cm for both species and increasing the mesh size from 80 to 90 mm. This study analyzes data on annual landings and discard estimates from 2019 to 2021 and uses computational simulations to assess the potential effects of changing MCRS and mesh sizes on discards, landings, catches and the economic consequences. Our results show that a 25 cm MCRS for plaice could decrease discarding by 13 to 18% while increasing landings by 28 to 34%. A MCRS increase to 25 cm for sole was predicted to increase discards by 10 to 24% while reducing landings by 5 to 9%. Increasing the mesh size to 90 mm reduced total catches for both species (16% and 25% for plaice and sole, respectively) and largely negated changes caused by MCRS. Both species exhibited decreased discards with the larger mesh size simulations (plaice: 10 – 48%; sole: 32 – 64%) with sole landings being reduced (8 – 25%). Increasing the mesh size versus a shift in MCRS may have a more prominent effect on the discards of sole and plaice, however, potential changes to landings must be considered as well when evaluating potential economic and environmental consequences. Economic analyses show that the change in MCRS for both sole and plaice in combination does have a small effect on total income for the main groups of vessels targeting these two species. The decrease in sole landings is almost completely compensated by the increased landings from plaice resulting in a total reduction of landings value of 2 and 0% for euro cutters and large beam trawlers respectively. The reduction in sole landings resulting from an increase in mesh size to 90 mm had an adverse effect on the landings value for both types of vessels and their economic performance. Total value of landings decreased by 9% for both euro cutters and large beam trawlers, causing lower or negative profitability. We assume that landings of other species would also be affected by the mesh size increase, though the analysis suggests a limited impact (5% reduction). It is evident that lower sole landings would continue to affect revenue in the ensuing years after increasing the mesh size. However, considering the degree of uncertainty surrounding the future costs and earnings of large beam trawlers and euro cutters, the economic consequences from reduced landings and the possibilities of the fishing fleet to cope with such changes remains unclear.

In het kader van de Partiële Herziening van het Programma Noordzee 2022-2027 is een beoordeling van de sociaal-economische effecten van windparkontwikkeling op de visserij nodig. Hiervoor zijn kwantitatieve historische data verzameld en zijn gesprekken gevoerd met vissers en handelaren. In de periode 2010-2019 werd gemiddeld 1,3 miljoen kg vis per jaar aangeland vanuit de onderzochte gebieden, wat daalde naar 0,74 miljoen kg per jaar in 2020-2022. Van de Nederlandse aanlandwaarde van langoustines komt 8,1% uit Gebied 6/7. De gebieden zijn het belangrijkste voor de visserijregio’s Urk (3,2%) en Kop van Noord-Holland (2,1%). Gebied 6/7 is het belangrijkst voor de Nederlandse kotters met 2,5%. Crowding effecten kunnen zich voordoen als gevolg van sluiting van gebieden. Volgens gesprekken met platvishandelaren is platvis belangrijk voor de marge van de vishandel.