SEAwise Report on status of ecological indicators in multispecies-multifleet management evaluations under changes in fish productivity adapted according to input from review workshops

The SEAwise project works to deliver a fully operational tool that will allow fishers, managers, and policy makers to easily apply Ecosystem Based Fisheries Management. SEAwise Task 6.2 aimed at incorporating environment and ecosystem considerations into enhanced multispecies-multifleet predictive models, allowing to simulate alternative management strategies using these models and to analyse the set of resulting ecological and socio-economic indicators. The work conducted in SEAwise was presented to stakeholders in specific SEAwise review workshops held together with advisory council members in 2025. The workshops covered the North Sea, Western Waters and Mediterranean Case studies. The workshops gathered stakeholder feedback, and the aspects addressed. Aspects related to ecological dimension of management strategy evaluation are addressed in this deliverable whereas socio-economic aspects are addressed in Deliverable D6.6. The description of additional climate scenarios, of ecological indicators and on uncertainty is integrated in this deliverable together with new scenarios that were simulated to address stakeholder feedback.

In the Bay of Biscay, additional simulations were performed with FLBEIA to explore the effect of a change in stock productivity for the northern hake and albacore stocks. This productivity change propagates to landings, SSB and recruitment, as well as gross value added but does not modify the total fishing pressure. In the Celtic Sea, additional forcing for climate change scenarios were applied to StrathE2E, and despite their differences in projected sea surface temperature (SST) and nutrient inputs, the models produced similar future behaviour of the ecosystem and stock dynamics. In the North Sea, the proportion of fishing revenue that was linked to Lusitanian species and cephalopods was investigated, ranging from 6% to 41% depending on the areas, and therefore indicating an already large contribution of warm species to fisher’s revenue. Moreover, emphasis on alternative management strategies that relies less on cod was conducted through the comparison of two of the scenarios already available in previous deliverables. This highlighted some opportunities for stocks that will perform better and costs for the stocks that will perform worse. In the Eastern Ionian Sea, alternative scenarios with a different allocation of effort reduction were explored, together with the simulation of a more extreme warming scenario. These scenarios produce better ecological outcomes than the ones simulated so far. In the Adriatic and western Ionian Sea results from the BEMTOOL model show that climate change is expected to negatively affect the total catch of hake and red mullet. In particular, under climate change, the status-quo fishing scenario is the scenario with the lowest SSB and catch of all the target stocks in the long-term. The scenario focused on achieving the MSY target of crustaceans provided the best mitigation of climate impacts. Likewise, the results from EwE simulations show that climate change is expected to affect the system negatively across its components, cascading across trophic guilds.