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Shellfish Aquaculture in Welsh Offshore Wind Farms – The Potential for Co-location

18 August 2014

A shellfish aquaculture study regarding co-location with offshore wind farms (OWFs) has recently been completed for the SAGB. Originally developed by Mark Gray of the Sea Fish Industry Authority (Seafish) and James Wilson of Deepdock Ltd., this Welsh EFF project was designed to investigate co-location potential taking into consideration the needs of all marine users.

The Project Team consisted of Mark Gray, James Wilson, Martin Syvret (ASL), Andy FitzGerald, Matt Ashley (PML) and Catrin Ellis Jones. The final report covers aquaculture options, an operational guidance manual, planning tools and a protocol for developing aquaculture in OWFs. The key findings are summarised as follows.

Offshore Co-location Aquaculture Options - Shellfish Species

As it is the wind farms and not necessarily the aquaculture approach that are offshore, the types of aquaculture activities that were considered were a mixture of nearshore and more truly offshore  techniques. In the short-term the most obvious candidate for commercial culture operations in OWFs was considered to be the blue mussel (Mytilus edulis). The North Hoyle trials carried out by  Deepdock in 2010 proved that seabed mussel cultivation can be carried out without any negative impacts on Wind Farm Operators (WFOs) although further work is required to fully assess feasibility. The technology to grow mussels offshore on fixed gear already exists but needs to be refined through commercial- scale trials within an operational wind farm environment. Importantly, such trials would also allow an assessment of environmental impacts and economic performance of this technology within OWFs.

In the medium-term, once UK aquaculture operators have gained experience in operating in OWFs, then there will be an opportunity to diversify into other shellfish species. Trials with the Pacific oyster (Crassostrea gigas) and the native oyster (Ostrea edulis) have shown that both these species will grow successfully offshore and that disease loads and parasites may be reduced in the offshore environment. These two oyster species would therefore seem to be the reasonable candidates for trials after those for mussels.

In the medium to long-term there are a number of other species that may be worth considering for shellfish aquaculture co-location. The market demand for farmed king scallops would make this species worthy of investigation although a lack of reliable seed supplies may well hamper development of this species. The high-value European abalone is already cultured in French waters and it is possible that this species may lend itself to culture in nearshore wind farm sites. Lobsters for stock regeneration or enhancement were also considered in the study.

Macroalgae have been the subject of several offshore aquaculture trials. However, it would appear that at present the returns on seaweed cultivation for energy generation purposes would be too low to make this a viable option. The existing hatchery techniques for food-market macroalgae may be economically feasible although further research would be required in order to commercialise the production process.

Shellfish mariculture permissions & licensing

Key aspects with respect to co-location reviewed were the rights to and licensing required in order to under-take aquaculture activities offshore, both outside and within a wind farm. As part of the project work a stakeholder data gathering exercise on licensing for offshore marine aquaculture was carried out. The main findings are summarised as follows:

There are no provisions under the Sea Fisheries (Shellfish) Act 1967 for licensing of seabed cultivation activities beyond 6nm. However this was not thought to be a limiting factor on expansion of offshore marine aquaculture.

A Crown Estate Lease could be used to license suspended cultivation activities out to the 12nm limit but it is unclear what mechanism would apply in this respect beyond 12nm.

Previous investigative work and research carried out in the present study would indicate that the lease for a wind farm granted to the Wind Farm Developer (WFD) or WFOs for the purpose of producing electricity includes the entire area encompassed by the wind turbines. No rights are granted under the current lease agreements for WFOs or third parties to undertake any aquaculture activities within OWFs. There does appear to be uncertainty as to whether a Fishery Order (FO) for seabed cultivation could be granted for an area within an OWF and this requires further investigation.

Following the data gathering exercise three possible solutions to the issue of licensing of marine fixed gear aquaculture within OWFs have been proposed:

• Areas requested for aquaculture activities are ex-tracted from the wind farm lease.
• Agreement with the WFO to a doubling of the leasing of rights within the wind farm.
• The WFO requests an amendment to their current lease allowing them undertake aquaculture activities within the wind farm.

These solutions would however all require the agreement and co-operation of the WFOs and therefore dialogue establishing how safe and compatible working practises could be developed was considered essential and formed a central recommendation of the current study. Other findings and recommendations with respect to licensing and permissions were the following:

• A review is needed of the legislation covering licensing of marine aquaculture activities, both seabed and suspended, beyond the 12nm limit.
• The legal status, in terms of licensing, of multi-functional use of a leased area within a wind farm needs to be defined.
• It was recommended that the powers of Welsh Ministers to control the sustainable exploitation of sea fisheries resources under the Marine and Coastal Access Act 2009 be investigated to ascertain if this would include the issuing of FOs out to 12nm.
• It was recommended that UK government and UK marine planning authorities be asked to consider the policy or legislative changes that would be needed for UK waters in order to implement a requirement for developers of new offshore renewable energy sites to carry out and evidence that an investigation of the potential for co-location within offshore renewable energy sites has been undertaken.

Policy drivers

The current study carried out a review of UK and European policy drivers in order to highlight the extent to which Marine Spatial Planning (MSP) provides encouragement for co-location. In terms of the UK, the Marine Shellfish Aquaculture in Welsh Offshore Wind Farms – The Potential for  Co-location Policy Statement and Energy National Policy Statements offer the main encouragement for integration of aquaculture within OWFs in England and Wales. There is also direct encouragement for artificial reef development in OWFs and for mitigation that enhances populations of economically important species.

In a similar way, MSP is taking place across many other EU Member States, principally Germany, Belgium and the Netherlands. It was found that more direct encouragement for co-location of the two industries exists in neighbouring EU Member States’ policies, possibly as a result of the even greater demands on space in smaller national waters. The Case Studies that were presented revealed that marine planning is generally at an early stage but co-location investigations are being developed through interest from aquaculture industries, research institutes and facilitation from WFDs.

Operational issues

The co-location of aquaculture with OWFs presents a number of operational challenges. Compatibility assessments of marine activities indicate potential conflict of a moderate level of difficultly to accommodate co-location. However, the recent MMO co-location report made an important distinction between the difficulty of co-location of aquaculture in the direct vicinity of the turbines as opposed to the wider OWF area. In theory, co-location is possible so long as appropriate separation zones are provided – in practice, it is very hard to determine the magnitude of any separation zone when there are no commercial-scale examples of this type of co-location activity.

The Operational Sections of the study considered colocation in terms of the risk factors from an OWF perspective. As technological solutions are a principle aspect of making compatibility possible, various systems, infrastructure and equipment were also considered. Finally, practical implementation of these systems to attain compatibility was considered using a Welsh OWF site-specific context for illustrative purposes.

The study has shown that important lessons can be learnt from other sectors such as the submarine cable sector and its co-location interactions with OWFs. Similarly, technological solutions can be borrowed from related sectors such as the enhanced VMS developed for small inshore fishing vessels, which can provide regulators with high resolution real-time positional and status data. Both of these components are vital to ensure that zone separation is achieved through the setting of an appropriate proximity zones. This can then be monitored and verified to provide assurance to the OWF sector. Although some further work can be progressed to develop risk profiles to inform proximity zone discussions there are data gaps, particularly in relation to the lack of offshore aquaculture fixed gear experience.

A number of recommendations have been provided of which the initial requirement will be the formation of an Aquaculture & OWF Co-location Stakeholder Forum with capacity to assemble and finance Task Groups to progress specific work-streams such as technical assessments, protocol development and finally to support further offshore co-location trials. Ultimately, only a phased programme of adaptive management will provide both sectors with the experience and confidence to make co-location possible and with clear demonstrable benefits for all parties.

The Final Report is available via the SAGB website

For further information on this project please contact Mark Gray at Seafish (E-mail

August 2014

Further Reading

You can view the full report in the CEFAS Shellfish News by clicking here.

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