Throughout the SEAwise project’s lifetime the Baltic Sea has faced a number of critical threats and challenges. These range from stock collapse and environmental degradation, to unprecedented shifts in the geo-political landscape.
As a result of these significant changes to the state of the Baltic fisheries, and EBFM modelling limits, the SEAwise Baltic Sea Case Study has not produced results which fit within the framework of this Tool. More detail as to why can be found in the insights tab, and by heading to our case study in focus box.
While historically, over-fishing has played the largest role in stock declines, in more recent history, fisheries management has not been effective, and stocks are seemingly impacted by other non-fishing human activities.
Ecosystem Based Fisheries Management cannot appropriately address these challenges alone, to ensure healthy and sustainably exploited stocks. Broader Ecosystem Based Management, which considers trade-offs against other terrestrial based activities under continued climate change is necessary. Because of the limits of the tools of EBFM no full management strategy evaluation procedure was put in place for Baltic Sea Fisheries. Instead, the Baltic Sea case study participants targeted their research to cases where narrower ecosystem knowledge could contribute significantly to improved management of stocks.
These areas of research include how commercially-important fish stocks (including Western Baltic cod, herring, and sprat) are impacted by changes in environmental and ecological conditions. In addition, the team have conducted in depth studies into the natural mortality of key stocks, as a result of predation by marine mammals such as seals and cormorants, as well as due to other natural causes such as disease, hypoxia, and starvation. The team has also worked to predict changes in fisheries’ carbon emissions, fishing-related litter, seafloor impacts, and the accidental capture of marine wildlife such as harbour porpoise.
FILTERS
Assumes a trajectory of moderate warming (RCP4.5).
Assumes a trajectory of more extreme warming, driven by higher emissions, resulting in more severe impacts (RCP8.5).
An optimistic scenario, which asssumes no change in current climate.
Assumes a continuation of current effort and exploitation patterns.
Assumes the adoption of a more flexible PGY approach, with a less severe effort reduction to achieve 95% MSY for key target stocks.
Assumes a strict MSY approach, whereby effort and catch limits are reduced to achieve MSY for key target stocks.
Assumes an additional management scenario specific to the case (further details can be found above).
The Baltic Sea has undergone substantial fishing pressure on both its main commercial stocks: Atlantic cod and herring. In spite of drastic changes to fisheries management and international collaboration from the many jurisdictions surrounding this inland sea, many of the Baltic’s key stocks have collapsed and are closed to fishing or in low productivity states.
With high rates of nutrient run-off from the surrounding catchments of agricultural land, coupled to climate change driven warming and reductions in deep water exchange with the North Sea, species that inhabit the Baltic Sea are experiencing habitat degradation and loss. This squeeze between hypoxic waters and marine heatwaves in shallow areas, leaves little room for stocks to settle, grow, feed, and reproduce.
Our Case Study film makes the case for the management of these other human impacts and accounting for the whole-of the ecosystem to help fisheries sustainability in the Baltic.
Within the Glossary you will find definitions that are frequently used in the EBFM Tool.
| Terminology | Definition |
|---|---|
| Benthic Habitat | The lowest zone in a body of water which is inhabited by organisms. This refers to the surface of the seabed and/or the base layer (substrate) of the seabed itself and the organisms found there. |
| Bycatch | The unintentional capture of a non target species. This can include fish (e.g. bass) and non-fish (e.g. seal) species. |
| Choke species | When the total allowed catch is reached for one species, meaning the fishery has to close. This is to prevent vessels from accidentally catching more of the fully fished species – known as the ‘choke species’ – despite still having allocations remaining for other species. |
| Common Fisheries Policy (CFP) | A set of international rules for sustainably managing European fishing fleets and conserving fish stocks within the European Union. The CFP covers social, economic and ecological aspects of fisheries management within Europe. |
| Demersal Fishery | A fishery which targets fish found near to or on the seabed. This includes both large- and small-scale demersal fisheries. |
| Ecosystem Based Fisheries Management (EBFM) | An approach to fisheries management that takes a holistic overview of all ecosystem, social, and economic elements related to fisheries, including impacts on stocks, marine environments, social benefits, and heritage. |
| ETP Species | A species which is recognised by the IUCN, national legislation, or international agreements as being endangered. This can relate to both non-target fish species and species from other taxa, such as cetaceans. Many species which are accidentally caught by fisheries as bycatch are ETP* species. *Note that this term and acronym are sometimes switched to: Protected, Endangered, and Threatened (PET). |
| FMSY-Min | A management scenario which entails fishing according to a strict MSY approach, whereby fleets must stop fishing once the first species in their target mix reaches FMSY levels. |
| Food webs | The network of interconnected food chains of a community. |
| Full Time Equivalent | A measure of labour input of employment adjusted for part-time work or seasonal work, so that all labour is expressed in terms of ‘full-time’ jobs. |
| Geographical Sub-Area (GSA) | Officially defined marine subdivisions of larger subregions, used for fisheries management, scientific reporting, regulation and conservation measures. |
| GFCM | The General Fisheries Commission for the Mediterranean is a regional fisheries management organisation that aims to ensure the conservation and sustainable use of living marine resources and the sustainable development of aquaculture in the Mediterranean, Black Sea and connecting waters. |
| Gross Value Added (GVA) | The economic contribution of a producer or sector to the economy, represented by the revenues generated minus their fixed and variable costs. It can be interpreted as the economic gain from an activity. |
| Landing Obligation | Under the EU Landing Obligation catches of species regulated through catch limits or minimum size must be landed and counted against quotas. The aim is to prevent discards of unwanted fish at sea. |
| Management Measure | The specific elements of fisheries management aiming to control and steer fisheries activities in order to achieve desired outcomes (environmental, economic and social). |
| Management Strategy | A combination of policy instruments with associated management measures to achieve desired objectives. |
| Marine Protected Area | A geographic area which has been designated as protected, and as such may limit or prohibit some or all kinds of fishing. Around 10% of the surface of European seas has been designated in this way, although only 0.5% constitute “no-take” zones, with significant variation between regions. |
| Marine Strategy Framework Directive (MSFD) | Marine Strategy Framework Directive (MSFD) is a framework directive whose purpose is to protect the marine environment across EU marine waters, using an ecosystem-based approach, while allowing sustainable use of marine resources. The MSFD aims for EU member states to achieve or maintain Good Environmental Status (GES). |
| Maximum Sustainable Yield | The largest average catch that can safely be taken from a fish stock over time without negatively impacting its long-term reproductive capacity and sustainability. |
| Model Uncertainty | The difference between the model system and the real world. For example, this may be due to the underlying structure of the model or relate to limitations in our understanding of the system (e.g., the ecosystem) being modelled. |
| Multi-annual Plans (MAPs) | Multiannual plans are a core tool under the Common Fisheries Policy (CFP). They are used to manage fisheries so as to ensure sustainable exploitation of fish stocks, and often contain goals for fish stock management. Some plans contain a detailed and tailor-made roadmap for achieving objectives such as MSY, including fishing effort restrictions and technical measures. |
| Nursery | A subset of all habitats where juvenile fish occur, having a greater level of productivity per unit area than other juvenile habitats. |
| Observation Uncertainty | Imperfect observation of the true state of the ecosystem. This relates to the data used in the model and may be due to factors such as natural variability, how data is collected, or the tools used in data collection (e.g., how we sample the size of a particular fish stock). |
| Pelagic Fishery | A fishery which targets fish found in the upper or middle layers of the water column, spanning both large- and small-scale pelagic fisheries. |
| PGY | A management scenario which entails fishing according to a more flexible MSY approach consistent with Multiannual Plans for fisheries, whereby fishing can continue until, for example, an upper range of FMSY is reached. |
| Primary Production | The biological process where marine phytoplankton and other microorganisms use sunlight to convert inorganic carbon into organic matter, forming the base of the marine food web that supports all fish life. |
| Process Uncertainty | The difference between real world processes and how these are represented in the model. This may be due to limitations with respect to our understanding of the real-world processes involved (e.g., how different factors such as fishing, disease, and predation impact fish mortality) or simplification of complex processes. |
| Productivity | A measure of the rate at which the total biomass of a population grows. The processes that directly affect productivity are recruitment, natural mortality, and individual growth. |
| RCP 4.5 | Representative Concentration Pathway 4.5 is one of the several greenhouse gas concentration trajectories used for climate modelling and research. It represents a medium stabilization scenario, in which total radiative forcing (warming effect) stabilizes at approximately 4.5 W/m² above pre-industrial levels by the year 2100, without overshooting. |
| RCP 8.5 | Representative Concentration Pathway 8.5 is one of the several greenhouse gas concentration trajectories used for climate modelling and research. It represents a high emissions ‘business as usual’ scenario without additional climate policies, resulting in a radiative forcing of approximately 8.5 W/m² above pre-industrial levels by 2100 leading to high levels of warming. |
| Recruitment | The number of fish added to the exploitable stock, in fishing area, each year, through a process of growth (ie. the fish grows to a size where it becomes catchable) or migration (i.e. the fish moves into the fishing area). |
| Relative Benthic State | A measure of the impact of fishing on the health and composition of seabed ecosystems and organisms, compared to their undisturbed state. RBS is defined as biomass (B) relative to the carrying capacity (K) of the benthic community. |
| Spawning Stock Biomass | The total weight of the mature portion of a fish population capable of reproducing. It represents the biomass of fish that contribute to spawning and is a key indicator used in stock assessments and fisheries management. |
| Species | A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. |
| Status Quo | A management scenario which entails a continuation of current fishing effort levels. |
| Stocks | A fish stock is a sub-population of a particular species of fish, geographically or reproductively isolated from other stocks of the same species, and managed as a unit. |
A droplet legend is used throughout the EBFM Tool to convey the relative status of different categories in the EBFM Tool (e.g. how well fish stocks are faring), and expected changes in these categories, based on various future management and climate scenarios, from the current baseline. The legend is intended as a visualisation tool for communicating trade-offs, and is indicative rather than absolute.
The models used throughout SEAwise and in the development of this Tool aim to help us understand how the marine ecosystem interacts and reacts to changes in management and the environment. This understanding aims to help inform management decisions for sustainable Ecosystem Based Fisheries Management (EBFM). Our models investigate and predict the biological, ecological, and economic trade-offs of different management strategies under a variety of environmental and economic scenarios. Simulating any real life system entails some degree of uncertainty, and this typically increases with the complexity of the system being modelled. To ensure our models are informative and aid management decisions, quantifying their uncertainty and communicating these elements transparently is an integral part of SEAwise.
Further information on how SEAwise has managed uncertainty in our models can be found here.