This report is a deliverable of Work Package 5 (WP5 – Apply new methods in case studies) of the FP7 MareFrame research project. It documents the application of a large number of ecosystem models into the different case studies with the ultimate goal to provide the quantitative information required by the decision support tools developed in WP6.
For the purposes of this deliverable, the case studies are developed independently from each other and are reported as separate experiences. However, they share large part of the methodologies (ie., a pool of state-of-the-art ecosystem models) and they all rely on considerable interaction with stakeholders groups. In addition, all the case studies aimed to apply multiple ecosystem models and their implementation has been synchronised around case study specific fisheries management issues.

The Baltic Sea case study investigates the management of cod, herring and sprat fisheries in the central Baltic considering trophic interactions among these three stocks, and the uncertainty associated to climate and nutrient scenarios. The case study applied three complementary ecosystem models – ie. EwE, Gadget and a multispecies production model – with the intent to better evaluate the implications of alternative fishery management strategies at population, community and ecosystem level and to serve from tactical to more strategic decisions. The models share common key datasets managed through a case study database. They have been aligned to implement a minimum number of common scenarios, some of which are still under implementation, and their output are expected to be integrated into a decision support tool developed in co-creation with the stakeholders.

The North Sea stakeholders asked for a multispecies model to answer their concerns. This request fitted well with the aim of MareFrame project of removing barriers that currently prevent a more widespread use of an Ecosystem-based Approach to Fisheries Management (EAFM). The so called ‘Green model’ that was developed to meet this need is a front end model that emulates the results of more complex models using simple approximations and also builds on to these the required social, economic and GES outputs. This results in a model that is extremely transportable and stakeholder friendly, and which is able to highlight the various trade-offs of fisheries management actions. It can take results from a number of pre-existing and developing models for the North Sea. These include the pre-existing and well-reviewed SMS, EwE and Ensemble models together with various developments of the Charmingly Simple Model (CSM), the Multispecies Schaefer model and a proposed delay difference model. More area and fishers behaviour explicit models (the Amber and Red models) are also planned to address further stakeholder concerns. Collectively this wide range of models provide strength through diversity and complementarity.

For Icelandic waters there exist management strategies in the form of a quota system and catch rules for most commercial species, but all of this is in a single-species context. The stakeholders did not show much interest in changing the actual implementation, although quota allocations remain a concern. The most important scientific issues are to consider the effects of multispecies and technical interactions and whether the single species harvest strategies are still sensible in a multispecies context.

The west of Scotland faces several management issues: the stocks of cod and whiting in ICES area 6a are currently depleted and the population of grey seals, and consequently the predation mortality on gadoids, has been increasing for the past two decades. In collaboration with the stakeholders group a set of alternative management strategies has been identified to address these issues. These alternatives were modelled with the Ecopath with Ecosim ecosystem model for the west of Scotland which was updated for the occasion using the latest assessment and survey outputs. In addition, Good Environmental Status and socio economic indicators were computed from the model outputs to assess the performance of the alternatives strategies regarding ecosystem health and fisheries economy. Results showed the importance of considering trophic interactions when assessing different fishing scenarios. Applying single species FMSY values seems insufficient to bring cod within safe limits by the end of the 20 years simulation period. Unsurprisingly, the alternative with the lowest fishing mortalities across species returned the highest ecosystem indicators overall but resulted in the lowest biodiversity. Increasing fishing mortality on crustaceans and pelagic species increased profit in the short term but not on the medium and long term. All the alternatives tested, including the ones with the lowest and highest fishing mortalities, converged towards similar long term total profit at the end of the simulation period.
Two different model approaches were developed in the South Western Waters. The first consists in a bioeconomic model for the anchovy fishery in the Gulf of Cádiz. The main objective for this is to provide advice for an adaptive management (considering environment forcing) in contrast to the current management based on a fixed quota. The main environmental processes considered were sea surface temperature, Guadalquivir River discharges and intense easterly winds. Scenarios with fixed and adaptive TACs were tested. Adaptive TACs provides a higher stability in catches and profits with a reduced probability of collapse. The second consists a multispecies model for hake and dolphins in the Iberian Peninsula. The main goal is to explore management measures considering hake and dolphin targets. Stakeholders suggested scenarios to explore the consequences of delaying the achievement of MSY until 2020. This delay produces a higher stability in catches and revenue although reduces future yield and the recovery for hake and dolphins.

The Strait of Sicily case study focuses on the development of a tool to support the implementation of an ecosystem approach to fisheries management (EAFM) in a key fishing area of the Mediterranean Sea. The objectives of the case study have been progressively refined through the application of a co-creation approach with key stakeholders (i.e. fishers and fishers representatives, managers of local and national administrations, conservation NGOs, FAO and GFCM officers) and taking into account the objectives of the GFCM international management plan for bottom trawl fisheries exploiting deep water rose shrimp (DPS: Parapenaeus longirostris) and hake (HKE: Merluccius merluccius) in GSAs 12-16. The overall goal of the case study has been adapted to provide a Decision Support Tool for the application of EAFM in the area which could support the achievement of long term sustainability finding a balance between ecological and human well-being through good governance. Atlantis and Gadget ecosystem models have been developed to provide advice on the effects of different management scenarios in relation to the following four main management objectives identified in co-creation with the stakeholders: i) rebuilding overexploited stocks; ii) long-term continuity of the fishing activities; iii) same rules for all; iv) good environmental status.
Ecosystem modelling in the Black Sea case study was made using Gadget and EwE ecosystem models. The Gadget model includes 7 different populations or functional groups, with 3 fleets acting in 3 different areas (Romanian area, West Black Sea area and all Black Sea). Both the impact of the interactions between species and the impact of fisheries harvesting the species have been included in the model, and the model successfully reproduces trends in historical data. The EwE model considers 10 species or pool of species. Trophic relationships are modeled with a diet matrix representing the proportion of a prey in the diet of the predator. Both models indicate a sharp decline of the total turbot biomass, even when eliminating IUU, suggesting that a temporary ban on turbot fisheries is among the management measures to be considered.

A balanced foodweb model has been developed for the Chatham Rise case study area, and used to investigate the potential implications of seabed mining for phosphorite nodules. The Chatham Rise is a very important area for New Zealand commercial fisheries, and also supports a diverse seabird communities, marine mammals and deepwater corals. Proposals have recently been developed to mine the seabed within an area currently protected from benthic disturbance. The foodweb model was used to the trophic importance of different components of the foodweb, and then on the basis of expert knowledge of the life history of the different components, those most likely to be sensitive to the effects of mining, and the potential implications were identified. These results were used to inform the New Zealand Environmental Protection Agency in consenting decisions on the seabed mining application.

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