Fish and fisheries research to inform ScotMER evidence gaps and future strategic research in the UK: review

Evidence Gap FF.05: Strategic fisheries management

Review of current knowledge

UK fisheries management strategies and policies give due consideration to aspects relating to how the marine space can be best shared to ensure that the best decisions are made for the marine environment as a whole as well as for all those that depend on it (The Scottish Government 2020a, UK MPS 2011).

As competition for the marine space continues to increase, attention has been given in recent years to the potential for co-location of MRE with other activities and its potential role in fisheries management (Ashley et al 2014, Ashley et al 2018, Christie et al 2014, Roach et al 2018).

MRE projects may act as de facto MPAs or no-take areas, as the presence of infrastructure and associated works may limit the level of fishing activity that can be undertaken within their boundaries. Co-location of MRE projects and areas closed to fishing associated with management measures in MPAs could therefore minimise potential cumulative losses of fishing grounds to the fishing industry. This may be particularly the case for demersal towed gear fisheries as these are generally more constrained than static gear fisheries to operate within operational wind farms, and are more likely to be restricted in MPAs to protect qualifying habitats/species.

Furthermore, the presence of MRE infrastructure has potential to provide protection to fisheries resources, result in spill over effects and improve the productivity of some fisheries.

Studies where the impact of MRE development on fisheries resources and its potential role as a tool for fisheries management has been directly investigated are however limited to date. Roach et al (2018) investigated the ecological effect of a short-term closure of European lobster fishing grounds, associated with the construction of the Westermost Rough offshore wind farm, and found that the temporary closure offered some respite for adult animals and led to increases in abundance and size of the target species in the area. The findings of this study suggest that temporary closures of selected areas may be beneficial and offer a management option for lobster fisheries.

Robertson et al (2021) studied the potential for Gunfleet Sands wind farm to act as an oyster broodstock site for the Blackwater, Crouch, Roach and Colne Estuaries Marine Conservation Zone (MCZ), the only UK designation for native oyster beds. The study considered aspects such as environmental tolerance of native oyster, hydrodynamics, operational requirements and potential designs, and identified limited viability for a broodstock site at this location. It is understood that the findings of this study formed the foundation of a wider scoping analysis of over 50 UK offshore wind farms. Roberston et al (2021) reported that initial results from the wider scoping study identified several sites that may be suitable for restoration and habitat enhancement of native oysters and noted that the scoping is being extended to include other species and habitat enhancement opportunities. The results of this additional research are however yet to be published.

As described under "Evidence Gap FF.12: Reef/fish aggregation effect", extensive monitoring of fish and benthic communities has been undertaken outside of the UK within European offshore wind farms. Fishing is not permitted in the majority of these wind farms and therefore they act as closed areas to fishing. Monitoring programmes in some of these sites have identified that the abundance of some species has increased in the vicinity of the foundations and in the wider area (van Hal et al 2017, Degraer et al 2018).

Similarly, recent research using modelling tools to predict the effect of the spatial closure of an offshore wind farm in the Bay of Seine, France (Halouani et al 2020) found an increase of catches and a slight increase in the proportion of high-trophic level fish species associated with the closure. The influence of the predicted spill over effect was localised to areas around the wind farm, within a 3 km radius.

In addition to research and data from existing wind farms, data and lessons learned from studies undertaken in relation to the effect of closed areas to fishing within MPAs, can aid future investigations on the potential role of MRE projects in fisheries management. These studies generally suggest potential for positive effects in nearby fishing grounds, however, whether or not the spill over effects identified result in direct benefits to fishermen and the fishing industry is still poorly understood (Russi et al 2016).

The potential for fishing closures to result in positive effects, through spill over effects, or other mechanisms, should be considered on a case-by-case basis. Buxton et al (2014) note that spill over effects associated with closures are more likely in areas where a fishery is highly depleted and/or where management controls are absent.

In addition, when considering the potential for offshore wind farms to act as MPAs and play a role in fisheries management, the dissimilar nature of assemblages on the structures themselves to natural communities needs to be carefully considered (Ashley et al 2014).

Furthermore, it may be difficult to distinguish impacts associated with the introduction of hard substrate (i.e. reef effects) from those associated with potential reductions in fishing activity or closures to fishing. Cause-effect relationships should therefore be investigated to understand the contribution of each factor to observed changes (Vandendriessche et al 2015).

Next steps in research

As identified in the literature review above, limited research has been undertaken to date to assess the impact of MRE development on fisheries resources and its potential role as a tool for fisheries management. In order to address this evidence gap the following recommendations are proposed:

• Research within offshore wind farms where fishing is restricted to better understand if there is a recovery of habitats and species, timescales of such recovery and potential for spill over effects and associated benefits to fishermen;
• Research on the potential of MRE installations for stock enhancement and development of pilot studies at suitable individual sites.
• Research on the feasibility of co-location of MPAs and offshore wind farms in the UK context.
• Development of modelling tools to identify potential effects of fishing closures in wind farms to inform management decisions (i.e. see Holouani et al 2020).

Recommendations under "Evidence Gap FF.11: Reef/fish aggregation effect", would also be of relevance to inform strategic fisheries management options.