Evidence Gap FF.02: Accurate and validated method to predict fisheries displacement levels and locations
Review of current knowledge
The potential for MRE projects, particularly offshore wind farms, to result in loss of fishing grounds or restrictions in access leading to displacement of fishing effort, is one of the key concerns of fisheries stakeholders since the development of projects started in the UK and in other countries (Mackinson et al 2006, Hooper et al 2015, Reilly et al 2015, Hagos 2007, ten Brink and Dalton 2018).
Research and studies on fisheries displacement to date, however, have for the most part been focused on displacement effects associated with fisheries management measures such as closed areas (Dinmore et al 2003, Rijnsdorp et al 2001). In recent years this has been focused on displacement effects related to the implementation of management measures in Marine Protected Areas (MPAs) (ABPmer 2017, Vaughan 2017, Slijkerman and Tamis 2015, Goñi et al 2011, Greenstreet et al 2009).
Studies specifically focused on identifying displacement as a result of the introduction of MRE projects are limited. In the UK, Gray et al (2016) investigated the changes to fishing activity associated with six operational offshore wind farm projects in the Irish Sea (Robin Rigg, Walney 1 & 2, Ormonde, Barrow and Burbo Bank). This was undertaken through the analysis of available fisheries data (i.e. landings data, VMS, surveillance sightings, etc) and a consultation exercise via the circulation of questionnaires to local fishermen, fisheries managers and offshore wind developers. The study identified a large reduction in fishing effort and landings of demersal finfish in the area, most likely associated with reduced Total Allowance Catches (TACs) rather than as a result of offshore wind farm development. For the Nephrops fishery, it was found that landings had remained fairly stable before and after wind farm construction, however, the analysis of VMS data suggested a decline in trawling activity for Nephrops in Walney 2. In the other wind farms the decline in fishing activity appeared to be less obvious. The results suggest that there was a displacement of fishing effort to alternative grounds. The authors noted, however, that it was not known how much more effort, if any, was required to maintain landings.
In Belgium, trends in fishing effort and landings data from areas within and around various wind farms have been studied to help identify changes in fishing patterns (Degraer et al 2019). These investigations have found decreases in fishing effort within the wind farms (as expected given that fishing is not permitted within Belgian operational wind farms) and no significant changes in fishing effort and landings from the key fisheries in the area (Belgian and Dutch beam trawl fisheries). No clear avoidance or attraction towards the edges of the wind farm arrays was identified. In wind farms situated further offshore, however, deviation maps (comparing fishing prior and after the installation of the wind farms) suggested that fishermen may be slightly attracted to the wind farm edges. In addition, the results suggested that the presence of Belgian wind farms did not affect the efficiency of the beam trawl fleet in catching sole, one of key target species in the area. In the case of plaice, this study found indication of increased catch rates around wind farms.
The outcomes of a project recently commissioned by Marine Scotland, aimed at developing good practice guidance for assessing fisheries displacement ("Developing good practice guidance for assessing fisheries displacement by other licensed marine activities") anticipated to be available in 2021, are expected to provide good practice guidance that facilitates the development of standard methodologies for the assessment of displacement effects consistently across marine licenced activities, including MRE projects. Earlier work commissioned by Natural England (ABPmer 2017) also provides a comprehensive framework to aid the development of methodologies for assessing fisheries displacement, including recommendations for monitoring and research (ABPmer 2017). Whilst Natural England's study was focused on the effects of displacement associated with MPAs, its conclusions and recommendations are also of relevance with regard to potential displacement effects arising from MRE projects.
Key factors identified in Natural England's study in determining the potential displacement of fishing activities to other areas are outlined below (ABPMer 2017):
- Expectation or occurrence of localised 'spill over' effects;
- Availability of alternative fishing grounds (taking account of technical considerations of the gears used, etc);
- Knowledge of alternative fishing grounds;
- Distance from port (fishing range and steaming time);
- Individual fishermen strategies and preferences; and
- Availability of fishing rights and quota.
In the particular case of offshore wind farm projects in UK waters, however, as fishing within operational wind farms is permitted, the viability of fishing within them is also a key factor in determining potential fisheries displacement effects.
The level of compatibility that fishing can achieve with offshore wind farm projects is dependent on aspects such as project design parameters, fishing vessel and gear specifications, operational requirements, liabilities for damages to infrastructure and health and safety related issues. Key aspects of relevance in this context include:
- Minimum spacing and width of corridor clear of infrastructure between turbines;
- Windfarm design and configuration;
- Foundation type (floating vs. fixed foundations);
- Approach to cable burial, protection and monitoring;
- Fisheries liaison and communication strategy;
- Free-hanging dynamic cables in the water column (for floating offshore wind);
- Vessel manoeuvrability, operating patterns, and gear type (active vs. passive) and dimensions; and
- Level of contact of the fishing gear with the seabed (i.e. seabed penetration depths).
In this context it is important to note that comprehensive guidance with regard to fishing specific requirements and wind farm design compatibility is currently not available. Such technical guidance would be useful to enable accurate assessments of potential displacement effects associated with MRE projects in UK waters (see section on "Evidence Gap FF.14: Co-existence with commercial fishing").
In addition, it should be acknowledged that whether fishing activity resumes within a wind farm or whether it is displaced elsewhere, and the level at which this takes place, would also be strongly influenced by behavioural aspects. Individual skippers may have differing views with regard to operating fishing gear within operational wind farms.
As described above, aspects requiring consideration to assess fisheries displacement are wide ranging, covering environmental, behavioural, technical and economic factors. The development of accurate and validated methods to predict displacement therefore requires the use of complex modelling tools. Significant research, studies and models have been developed in recent years to assess and predict displacement effects associated with MPAs (e.g. Chollet et al 2016, Bastardie et al 2015, Hynes et al 2016, Girardin et al 2015, Tidd et al 2012, Greenstreet et al 2009). Existing tools developed to assess displacement in relation to MPAs could be adapted to take account of wind farm specific parameters (e.g. viability of fishing within wind farms) and contribute to inform displacement assessments in respect of MRE projects.
Approaches which develop modelling scenarios able to integrate displacement effects from relevant licenced activities and management measures (i.e. closed areas associated with MPAs) and that allow incorporation in the strategic planning process, rather than focusing on the effect of displacement from individual projects alone, would provide more realistic outcomes. In this context it is important to note that fishing effort displaced from a specific MRE project may be relocated at considerable distances and can be influenced by displacement effects which occur elsewhere as a result of other marine projects and activities. As fisheries displacement effects tend to be cumulative in nature, their assessment requires a strategic approach which takes account of impacts from other marine activities rather than a project specific focus.
Next steps in research
As described above, limited studies have been undertaken to date to understand displacement effects on commercial fisheries and the majority of these have been predominantly focused on displacement effects associated with MPAs rather than MRE development. This knowledge gap limits our ability to undertake accurate assessments of the effect of MRE development on commercial fisheries at the project specific level but also in a cumulative context.
As displacement associated with a given project is influenced by a wide range of factors, including changes to fishing activities as a result of other projects/activities, complex modelling tools will likely be required to aid the undertaking of robust assessments. Such tools should allow the integration of relevant licenced activities and management measures with implications for fisheries displacement in addition to MRE developments.
Considering the above, the following next steps in research have been identified in respect of "Evidence Gap FF.02: Accurate and validated method to predict fisheries displacement levels and locations":
- Undertaking of strategic studies and monitoring of changes to fishing activities and displacement associated with existing offshore wind farms in the UK; and
- Development of modelling approaches that allow the integration of relevant licenced activities and management measures with implications for fisheries displacement.
As the level of fisheries displacement that may occur in relation to MRE development is strongly dependent on the level of co-existence achieved between projects and commercial fishing, research recommendations under "Evidence Gap FF.15: Coexistence with commercial fisheries" are also of relevance to address current evidence gaps in respect of displacement effects.
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