Wild seaweed harvesting: strategic environmental assessment - environmental report

Investigates the sustainability and potential environmental impacts of wild seaweed and seagrass harvesting, maerl extraction and removal of beach-cast seaweed.

Non-Technical Summary

What is the role of this Strategic Environmental Assessment?

The Environmental Assessment (Scotland) Act 2005 requires the assessment of certain plans, programmes and strategies (including policies) that may have significant effects on the environment. Strategic Environmental Assessment ( SEA) is the process used to fulfil this requirement, and includes consultation with the public and the Consultation Authorities.

A screening exercise was carried out by Marine Scotland and this found that wild seaweed and seagrass harvesting has the potential to give rise to significant environmental effects unless it is undertaken in a sustainable manner. It was concluded that an SEA should be prepared. A scoping exercise was carried out and a Scoping Report was prepared and issued to the Consultation Authorities in November 2015. This document set out the approach to and scope of the SEA.

Marine Scotland commissioned ABP Marine Environmental Research Ltd. ( ABPmer) to provide technical support to the SEA and this Environmental Report. The purpose of this report is to document the findings of the SEA.

How was the Strategic Environmental Assessment undertaken?

Schedule 3 of the Environmental Assessment (Scotland) Act 2005 sets out the environmental factors or topics that may be subject to SEA. The scoping exercise identified that the following SEA topics should be scoped into the SEA and assessed:

  • Biodiversity, flora and fauna;
  • Climatic factors; and
  • Cultural heritage.

The potential environmental effects of harvesting on each of these SEA topics have been assessed using the set of Key Questions that were developed at the scoping stage. These questions are based on a consideration of the ecological functions and ecosystem services provided by wild seaweed and seagrass, a review of the existing environment, the potential effects of wild harvesting and relevant environmental protection objectives. They also take account of the comments received from the Consultation Authorities.

The assessment is structured in a narrative style, centred on exploring the issues that the Key Questions raise. This narrative approach provides explanatory text to support the findings of the assessment, and record the evidence used in reaching its conclusions and recommendations.

This SEA has built on and updated existing information collected through the SEA for seaweed cultivation that was published for consultation in August 2013 alongside a draft Seaweed Policy Statement. Information from other sources including but not limited to the National Marine Plan have also informed this SEA. The SEA has also taken into account information provided by respondents to consultations.

Why are seaweeds and seagrasses important?

Seaweeds and seagrasses play a key role in marine and coastal ecosystems. Some are able to modify the environment ( i.e. "ecosystem engineers") and support high levels of marine and coastal biodiversity. As primary producers, they are also critical for supporting food webs which in turn contribute to fish and shellfish productivity. The importance of seaweeds and seagrasses in ecological functioning is recognised by the fact that they are used as indicators for assessing the ecological status of Water Framework Directive ( WFD) water bodies and are included in a number of nature conservation designations.

Seaweeds and seagrasses also provide a number of ecosystem services, including natural hazard protection and climate regulation. Kelp forests and seagrasses are known for their capacity to weaken waves and reduce currents. Beach-cast seaweeds provide nutrients to dune habitats which in turn stabilise local sediments and contribute to coastal protection. In terms of climate regulation, seaweeds and seagrass habitats are important carbon stores and some may act as carbon sinks.

What is the current state of the environment?

A wide range of physical conditions are experienced along the coastline and inshore waters of Scotland from exposed areas characterised by rock to sheltered sandy bays, mudflats, sandflats and sea lochs. Water quality in Scotland as a whole is generally very good. However, there are some localised areas of concern, such as the Firth of Forth and Moray Firth.

Scotland's seas are among the most biologically diverse and productive in the world. Scotland's marine biodiversity is protected by a range of European, UK and Scottish-level designations. Key habitat types include estuaries; lagoons; large shallow inlets and bays; mudflats and sandflats not covered by seawater at low tide; reefs; sandbanks which are slightly covered by seawater all the time; submarine structures made by leaking gases; and submerged or partially submerged sea caves. Key animal species include cetaceans (whales, dolphins and porpoises), seals, seabirds, fish (including sharks, skates and rays) and turtles.

Climate change is predicted to lead to an increase in water temperature and acidity, a rise in sea levels, changes in wave heights and changes to coastlines. Climate change is already having an impact on weather patterns. Changes in temperature, levels and timing of rainfall, and more extreme weather events are all expected to occur, affecting other aspects of the environment.

Scotland's seas and coasts support a wide range of historic and archaeological sites. These are found on the coast, the foreshore and the seabed, ranging from the remains of ships and aircraft lost at sea to harbours, lighthouses and other structures along the coast

What are the potential environmental effects of wild harvesting?

The SEA has identified that the sustainable extraction of maerl is not possible and that harvesting of maerl should be prohibited. Although the evidence indicates that the sustainable harvesting of seagrass might be possible, the seagrass beds found in Scotland are typically small and unlikely to support wild harvesting activities. The commercial harvesting of seagrass should therefore also be prohibited.

Current small scale ( i.e. artisanal) hand cutting or picking of wild seaweed in Scotland is unlikely to result in significant adverse environmental impacts. It is therefore considered that these small scale activities can continue to be undertaken sustainably through existing practices ( i.e. landowner permissions) and consultation with Scottish Natural Heritage. There is a risk that small seaweeds (namely green and red seaweeds) could be completely cleared from an area by these small scale harvesting activities. However, there is no information available on what would be considered a significant volume of removal for these small seaweeds and therefore at this stage in the absence of evidence it is not possible to propose a threshold for triggering a marine licence requirement for these activities.

The SEA has confirmed that significant adverse effects can occur as a result of large scale ( i.e. industrial) mechanised harvesting of seaweeds (namely kelps and wracks). These primarily relate to impacts on the ecological function of these important habitats (namely ecological interactions, food web dynamics and production) as well as on the ecosystem services that they provide (including coastal protection and carbon sequestration), and that these impacts may be further exacerbated in the future with the predicted effects of climate change. Harvesting also has the potential to affect cultural heritage (namely underwater heritage assets and the collection of beach-cast seaweeds by crofters).

Key issues include but are not limited to:

  • Loss of habitat and/or shelter for a range of plants and animals, alongside loss of direct and indirect food sources. This has consequences for detrital grazers and suspension feeders, as well as higher trophic levels, e.g. mammals, birds and fish;
  • Loss of nursery grounds for juvenile invertebrates and fish, with consequences for higher trophic levels and commercial fish stocks;
  • Loss of the physical modification effects of seaweed, e.g. wave damping, which may result in increases in coastal erosion and/or flooding events;
  • Loss of carbon stores and sinks provided by some seaweed species; and
  • Loss or damage to cultural heritage assets and reduction in resource available to crofters.

Many of these effects are likely to be site specific and will depend on a range of factors, including the species to be harvested, the harvesting method, the amount taken, the timing (season) of harvest, the harvesting location and its environmental context, and the time allowed for regeneration prior to harvesting again. Harvesting practices, most notably the extent and scale of harvesting ( i.e. frequency of harvesting, the proportion of a seaweed community harvested, and the proportion of an individual plant harvested) and the species harvested have been identified as key factors in ensuring plant regeneration and recovery of harvest areas, and ensuring the sustainability of the resource and the biodiversity it supports.

How can significant effects be mitigated?

The specific mitigation that is appropriate will depend on the extent and scale of extraction which will only be known at the project level. In particular, it is important that any monitoring requirements reflect the scale, scope and complexity of the harvesting, as well as the level of risk (and confidence limits) of an ecological or environmental impact. The cost should also not be excessive compared to the estimate of income due from the harvesting activity.

A range of potential mitigation measures have been identified that developers will need to consider at the project level where relevant and necessary. These are based on relevant Codes of Conduct for seaweed harvesting and also recommended sustainable practices. The measures will include consideration of areas around the Scottish coast that are particularly sensitive to harvesting and where industrial scale harvesting may be restricted or unacceptable, including:

  • Coastal areas that are wave exposed, prone to erosion and where kelps dissipate wave energy ( e.g. Uists);
  • Designated sites that could potentially support kelps or wracks ( i.e. SACs, PMFs and MPAs);
  • Seal haul out sites;
  • Charted archaeological features (wrecks) and Historic Marine Protected Areas ( HMPAs);
  • Areas where beach cast seaweed is used by crofters.

What are the likely cumulative effects of a new licensing mechanism with other plans?

The focus of licensing wild harvesting is to ensure it is only undertaken where sustainable. The principles of sustainable development and protection of Scotland's marine environment are also key threads of wider Scottish policy ( e.g. the National Marine Plan, Scottish Biodiversity Strategy). The licensing of wild harvesting activities therefore provides a means to manage negative environmental impacts.

Licensing also helps industry in developing a better understanding of expectations for future applications in relation to wild harvesting. Furthermore, by ensuring that wild harvesting activities do not result in significant negative environmental impacts, the licensing complies with environmental protection objectives, such as the WFD.

What are the outcomes of the Strategic Environmental Assessment?

On the whole, this SEA and the consideration of potential cumulative and synergistic effects demonstrate how the nature and extent of any potential impacts, depends on the method and scale of harvesting, and the composition and sensitivity of the corresponding marine ecosystems. It also demonstrates the interdependence of licensing, the seaweed industry and its stakeholders, the processes currently in place, and the combined role that they will need to play to ensure the sustainable growth of wild harvesting industries into the future.

The SEA has confirmed that significant adverse effects can occur as a result of large scale ( i.e. industrial) mechanised harvesting of seaweeds (namely kelps and wracks).

Although there is no evidence that small scale artisanal hand cutting or gathering of living and beach-cast seaweeds at discrete locations has significant environmental effects, there is the potential for significant cumulative effects as a result of multiple harvesting activities. However, we do not know what the cumulative effects of a large number of small-scale activities being undertaken within the same geographic location or the cumulative effects of potential small scale harvesting operations in conjunction with large scale industrial operations would be. These would need to be considered in the cumulative assessments of individual licence applications.

Following on from this SEA, Marine Scotland intends to prepare a guidance note for regulators and applicants. This will include information on key issues associated with wild harvesting that have been identified in the SEA. It will also include information on issues that fall outside the scope of the assessment but will need to be considered at the project-level by industry. The guidance note will also present mitigation measures that might be required to ensure future wild harvesting activities do not result in any significant adverse effects and are undertaken sustainably.

GIS data layers that have been created as part of this SEA, namely the distribution of the current seaweed and seagrass resource and will be included on Marine Scotland's National Marine Plan interactive ( NMPi) site.

How do I respond to the consultation?

A consultation on this Environmental Report will follow. Public views and opinions on this Environmental Report are invited.

Reponses need not be confined to the consultation questions, and more general comments on the Environmental Report and the Consultation Document are also invited.

What happens next?

Following the consultation period, the responses received will be analysed and reported. Key messages from the various stakeholder groups will be highlighted, and the findings of the analysis will be taken into account.


Back to top