Scottish Seaweed Harvesting

In the summer of 2018 proposals were made by a commercial company to mechanically dredge seaweed from the Scottish coastline. Angling, conservation and environmental groups all expressed concern over the impact that such activity would have on Scotland’s marine ecosystem. In November 2018 the Scottish Government voted to ban the practice of dredging for kelp, preventing the company from going ahead with its plans. The move was welcomed by campaigners and anglers alike and was seen by some as a positive decision as the health and welfare of the marine environment was put ahead of commercial interests.

Plans to Harvest Seaweed

Marine Biopolymers Ltd (MBL) is an Ayr-based company founded in 2009. Its website states that it has a “focus is on extracting high-value components from brown seaweeds for use in a range of applications, primarily ‘human’ ones such as food and pharmaceuticals” (1). The company made national headlines in 2018 when news emerged that they had applied for a five-year marine licence to “sustainably harvest wild kelp (Laminaria hyperborea) on the west coast of Scotland.” (2) A scoping report (entitled Wild Seaweed Harvesting which is available online – link in the references below) supported the application and stated that there was a wet weight of 19.7 million tons of wild kemp in Scottish waters and the company would only be harvesting around 30,000 tons, around 0.15% of the total.

Money can be made by harvesting seaweed.
Money can be made by harvesting seaweed.

Specially designed vessels would be used to harvest the kelp, and while this would be a new industry in Scotland it was already established and successfully and sustainably operating in Norway, Iceland and France. The report also stated that the harvesting and processing of wild kelp had the potential to bring “employment and diversification opportunities” to economically challenged areas in Scotland (2).

Opposition, Arguments and the Economic Value of Seaweed

Kelp and other forms of seaweed have long been valuable marine resources. Traditionally harvested by being collected by hand from the shore, seaweed has been used in the manufacture of glass, fertiliser and cosmetics. However, MBL’s aim to harvest kelp in industrial quantities is driven by the range of new applications which kelp can be used for. These include the nanocellulose in seaweed being used to make slow-release drugs to treat cancer and other serious illnesses, medical uses such as making next-generation implants and meshes and there are even plans to use seaweed as the main component in lightweight but super-tough body armour which could have significant police, security and military applications. It would only take one of these new uses for seaweed to become mainstream to make the value of seaweed rapidly increase in value to a multi-million pound industry, with clear benefits for the companies set up to harvest it. With this in mind, it is easy to see why being allowed to expand seaweed harvesting along the west coast of Scotland was an extremely attractive proposition for MBL.

Despite this potential economic significance, MBL’s plans were immediately criticised by groups including green party politicians, environmentalists, conservation charities and anglers. It was pointed out that a wide variety of animals live in and around kelp forests, including sea sponges, crustaceans, small fish and larger species such as cod, pollock, conger eels, wrasse, coalfish and many other marine creatures. Any form of kelp removal would have a potentially devastating impact on these species, both in terms of bycatch and habitat destruction. Furthermore, there could also be issues caused on land as the huge amount of kelp around the Scottish coastline helps absorb the force and power of waves. A reduction in kelp levels had the potential to leave some areas more likely to suffer from coastal erosion and possibly flooding.

Laminaria hyperborea
Laminaria hyperborea seaweed, the type which would be harvested in Scottish waters.

The fact that MBL was planning on mechanically dredging kelp was one of the biggest causes of concern. The type of kelp the company was aiming to harvest was Laminaria hyperborean, a large species which can reach lengths of three metres (10ft) and is usually a brownish colour. Unlike land plants, Laminaria hyperborean do not have roots and instead anchor themselves to the seabed with tentacle-like feet known as rhizoids. There were fears that dredging for kelp could simply remove entire seaweed plants from the seabed (rather than part of a seaweed plant which could then grow back) leaving large areas devoid of seaweed. In public comments on the scoping report Calum Duncan of the Marine Conservation Society expressed concern over the proposals saying that kelp habitats are “Vital ecosystems that absorb the power of waves along stormy coasts, lock up millions of tonnes of carbon every year and provide shelter for hundreds of species … mechanically stripping swaths of pristine kelp forest clean from the reef at the scale proposed simply cannot be considered sustainable” (3).

Existing small-scale kelp harvesters also expressed concern. Ailsa McLellan who gathers kelp by hand told the Guardian that even if MBL were “the most careful company in the world” there would be “no pressure” for other companies to follow the same procedures as there is no legislation or regulations to protect wild kelp from unsustainable harvesting (3). She also pointed out that there were strict rules that small-scale seaweed harvesters had to follow regarding bycatch while MBL could potentially be allowed to “go at it with a dredge” (3). MBL co-founder David Mackie claimed in a BBC interview that it was not possible to dredge a rocky seabed, so the company would not actually be dredging for kelp, and warned that banning or restricting kelp harvesting could see Scotland miss out an industry which could be potentially worth £300 million.

Sir David Atenborough
Sir David Attenborough.

In October 2018 the groups aiming to prevent kelp dredging in Scottish waters received a boost when the world-renowned naturalist Sir David Attenborough spoke out on the issue. He said that dredging for kelp was a:

“Wholly short-sighted measure that risks the wholesale devastation of our kelp beds … these kelp forests … not only form an important part of the food chain, but also act as a vital habitat for a wide array of species” (4).

A petition against kelp dredging was launched gaining over 26,000 signatures, underlining the strength of public feeling.

Ban and Future Developments

In November 2018 the Scottish parliament voted to ban mechanical kelp harvesting methods which prevent seaweed from re-growing. These extra controls would prevent the removal of full plants using dredges and meant that the large-scale dredging proposed by Marine Polymers Ltd could not go ahead (5). Scottish Environment Secretary Roseanna Cunningham also announced a review into all aspects of kelp harvesting and stated that the aim was not to “Block the future development of forms of harvesting which might in time be established, through a proper assembling of the evidence, as sustainable” (5).

It may well be the case that the Scottish government has learned lessons from the nation’s fish farming industry. Recent years have seen the Scottish government promote fish farming and encourage the growth of the industry with little consideration given to the significant environmental and animal welfare issues that the intensive farming of fish causes. This has led to a backlash from conservationists, environmental campaigners and the public and calls for a review of the entire Scottish fish farming industry. Following this, it would be unsurprising if the Scottish government now takes a more cautious approach to expanding any form of aquaculture. A spokesperson for Marine Biopolymers Ltd said that they were “disappointed” with the decision but welcomed the review into kelp harvesting (5).

Seaweed Harvest
Sustainably harvested seaweed being transported by road in Ireland [file picture].

The future for kelp harvesting in Scotland, and in all probability across the entire UK, is therefore unclear. The failure (for now at least) of Marine Biopolymers Ltd to gain permission to carry out the type of dredging that they initially planned could mean that only low-impact methods of gathering wild will be permitted in the future. This could take the form of seaweed farming. This form of seaweed harvesting is already in its early stages in Scarborough in North Yorkshire where the government’s Coastal Communities Fund has awarded a £472,000 grant to develop a large-scale seaweed farm (6).

In December 2019 the issue of seaweed dredging was again brought into the news when media reports emerged stating that mechanical dredging trials were set to take place in 2020 along the west coast of Scotland. The Scottish government denied these claims and stated that plans for a “scenario mapping” study had been misinterpreted and stated on the Scottish government website that “no trials have been commissioned or are planned to mechanically harvest kelp” (7).


  1. Marine Bioploymers Ltd – About [Undated].
  2. – Wild Seaweed Harvesting Scoping Report, July 2018.
  3. The Guardian – Kelp Dredging Proposal Criticised by Scottish Conservationists, 24th August 2018.
  4. ITV News – Sir David Attenborough Demands MSPs Protect ‘Globally Important’ Kelp Beds, 24th October 2018.
  5. STV News – Scottish Parliament Curbs Mechanical Kelp Harvesting, 21st November 2018.
  6. BBC News – Experts Plan Large-scale Seaweed Farm in Scarborough, 5th April 2019.
  7. – Statement on Recent Media Commentary Around Mechanical Dredging Trials, 13th January 2020.

Note: This article was written in late 2019. Any developments since then will not be reflected in this article.