SIFT’s work on seaweed covers two main areas: prohibiting the industrialised extraction of wild kelp seaweeds; and promoting the regulation of sustainable seaweed cultivation.
Prohibiting industrialised wild kelp dredging
Help the Kelp
In 2018 SIFT established the ‘Help the Kelp’ campaign to prohibit the dredging of kelp – a brown seaweed which is vital for the coastal ecosystem, and can be processed into polymers used in food processing and other industrial sectors.
Kelp dredging involves a heavy metal dredge up to 4 metres in width, suspended from a floating vessel, being dragged through kelp beds so as to uproot and gather entire kelp plants. The process gathers large quantities of kelp. But it also prevents the plants from re-growing.
Working with many stakeholders, the media and politicians from across the Scottish Parliament, our campaign succeeded in ensuring that kelp dredging for commercial harvesting purposes became illegal in Scottish waters in 2019. More specifically, the Parliament enacted provisions to ensure that kelp harvesting can only take place where the individual kelp plant is not killed. This ensures that mechanical dredging cannot take place, but that small scale and carefully targetted wild kelp harvesting, as well as cultivation, can continue.
(Photo credit: Howard Wood)
Research from Norway where mechanical dredging for kelp is permitted found 92% fewer young fish in dredged areas. It is for that reason that many Scottish fishermen oppose this damaging activity. In addition, conservationists and other stakeholders value kelp forests’ roles as buffers against storms and as habitat for a wide array of other species. Research has shown that more than 200 marine species can inhabit kelp holdfasts (the part of the plant that is attached to the sea bed), and many more rely on the stems and fronds above.
As kelp forests are one of the few remaining undamaged ecosystems in the Scottish marine environment, the statutory protection they gained under Section 15 of the Scottish Crown Estate Act 2019 was a significant and rare example of successful Scottish marine conservation.
Seaweed aquaculture
Seaweed aquaculture in Scotland typically involves the cultivation of kelp seaweeds in coastal seaweed farms comprised of multiple long-lines which are suspended below the water surface and fixed in place by a system of buoys and anchors. Coastal locations are preferred because these waters are accessible, sheltered, and typically have suitable nutrients, salinity and temperature to maximise growth. The lines, which are pre-seeded with kelp spores in hatcheries, are typically placed in the sea in the autumn with a view to harvesting the following spring or early summer. Harvesting is usually conducted from a boat, with the seaweed either being removed from the long-lines by hand or mechanical cutter. It is then transferred to land for processing.
(Photo credit: Cat Wilding)
Benefits and significant risks
SIFT recognises the many socio-economic benefits to be gained from a successful seaweed cultivation sector in Scottish waters. So we support the progressive expansion of the sector – provided that it’s cumulative effects on marine ecosystems and on other legitimate users of the marine environment are taken into account. As seaweed farming faces a range of challenges, including competition for space, and the limited availability of processing facilities, there are concerns that the sector will become dominated by well-capitalised corporations with little direct relationship to coastal communities. To support the development of a Scottish seaweed sector, SIFT published a report Facilitating development of the seaweed cultivation sector. This sets out pathways for the sector and assesses the role of cooperatives and alternative models for collaboration. We have also published a Regulatory Vision for the seaweed cultivation sector which sets out our policy aims.
In addition, with the Marine Conservation Society, we have published Guidelines for environmentally responsible seaweed cultivation. This guide, the first of its kind in the UK, is intended to help UK seaweed businesses understand the potential environmental impacts of both seaweed aquaculture and small scale wild seaweed harvesting, and to help them incorporate this knowledge into their projects before commencing development. The guidelines are also intended to outline environmental best practice and highlight other resources that may be informative. It is not a standard, so it does not offer accreditation or certification. We welcome the fact that our publications have contributed to the 2025 publication by the Scottish Seaweed Industry Association (SSIA), of its Code of Good Practice.
The resolution of the threat from kelp dredging, and the subsequent promotion of seaweed farming illustrates how a balance can be achieved between protecting Scotland’s natural environment and developing industries of the future.
