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. |
| 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. |
| 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 Strategy Framework Directive (MSFD) | European legislation which aims to protect and achieve good environmental status (GES) of the EU’s marine environment. It enshrines the ecosystem-based approach as the legally-binding and operational principle for managing that environment. |
| 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. |
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.