The fourth Workshop for the Technical Evaluation of EU Member States’ Eel Regulation Progress Reports (WKEMP4) prepared and reviewed scientific analyses to provide material to answer a special request from the European Commission. The report reviews, compiles, and analyses data and information received by ICES. In most instances, data gaps and inconsistencies curtailed evaluation of the effectiveness of Eel Management Plans (EMPs), management measures, and monitoring programs.
Employing best available data and analyses in assessing EMP trends, WKEMP4 concludes that in most EMPs escapement and mortality are still far from the explicit or implicit regulation tar-gets. In addition, there is no evidence that escapement is increasing, as combined trends submit-ted by countries show a slight decreasing trend, and anthropogenic mortality remains generally high having decreased only in a limited number of EMPs.
Biomass indicators, as reported by the Member States, suggest that the management target of 40% of pristine silver eel escapement (Bcurrent/B0 ≥ 0.4) has been achieved in 12 of 55 reporting EMPs, which is less than in the initial year of reporting (16). Relative trends suggest that escape-ment is lower today as compared to the initial year of reporting in 39 of the reporting EMPs escapements, 30 displaying a significant downwards trend. The biomass target implies a lifetime anthropogenic mortality of ΣA = 0.92.
Mortality indicators, as reported by the Member states show that in 34 of 55 reporting EMPs ΣA is lower than the implicit mortality target (0.92) compared to 23 that were below in the initial year of reporting. In 30 EMPs, mortalities are lower currently as compared to the initial reporting (14 with a significant decreasing trend), whereas an increase was reported for 19 EMPs (11 with a significant increasing trend).
Progress on implementing management measure is continuing for commercial and recreational fisheries, and trade; hydropower, pumping stations and obstacles; restocking; habitat improve-ment; governance; and scientific monitoring. A total of 467 measures (75% of the total) were deemed fully or partially implemented. The variation and gaps in the data submitted made it extremely challenging to determine the effectiveness of reported (types of) measures in the con-text of associated threats. In many instances, measures were not designed to be evaluated directly by biomass and mortality indicators. Ultimately, local expertise and adaptive monitoring and assessment plans of each EMP are needed to evaluate measure effectiveness.
Biomass and mortality indicators were not reported by all countries and those which reported had inconsistencies, mostly about whether and how restocking was included in the estimation of indicators, how pristine recruitment was estimated, and what estimation methods were used. This makes it difficult to reach conclusions for the whole stock. In addition, management targets are not consistently calculated which further impairs comparison between EMPs and evaluation of the status of the whole stock.
An analysis of the methods used to build the biomass and anthropogenic mortality indicators led to grouping the methods by type and evaluated possible threats and biases associated with each group. In the short term, using common methods to estimate anthropogenic mortalities should be possible and these should be applied for the next evaluation of the EU Member States progress report under the Eel Regulation in 2027. In the long-term, biomass, including pristine biomass, should be estimated using common methods and approaches, to make the comparison between countries possible.
Management measures influence mortality directly, whereas the possibility to influence biomass for a single EMU are limited and strongly depend on recruitment which, in turn, depend on the progress made in all countries in the eel range. Mortality targets should be explicitly agreed in addition to the biomass escapement target and focus on the management should be on mortality targets.