Do not allow mechanical kelp dredging in Scottish Waters.
Do not allow mechanical kelp dredging in Scottish Waters.
Kelp dredging is currently not allowed in Scotland. A company called Marine Biopolymers seek to change that, and have submitted a scoping report to Marine Scotland with a view to gaining permission to dredge over a large area of Scotland’s West Coast where they say there could be a ‘Significant’ Kelp dredge industry.
The importance of our wild kelp beds cannot be overstated. Any reduction of them is unacceptable. We call on Roseanna Cunningham to ensure that the Scottish Government DO NOT grant ANY licenses for kelp dredging in Scottish waters.
‘To grant this licence would be criminally short-sighted, and an act of pure indifference to all those current thinkers for whom too often in the past commercial advantage and arguable employment benefits have over-ruled protection of the natural world. Some things are more precious than business.’
Adam Nicolson, acclaimed author of The Seabird’s Cry and The Sea Room
Current kelp hand harvesting licenses specify that the holdfast, stipe (stalk), and a large part of the frond are left in-tact to allow the plant to regenerate. Dredging uses a large toothed metal head to rip the entire plant from the seabed, taking the holdfast, stipe, and all the life that is attached to it, the holdfast is cut off and lobbed it over the side. 'The biogenic habitat formed within a kelp holdfast generally harbors the most diverse assemblages' (Smale et al. 2013).
Marine Biopolymers describe the habitat that they want to dredge up as a ‘monoculture’, it is in fact ‘One of the most ecologically dynamic and biologically diverse habitats on the planet’ (Birkett et al., 1998), and Laminaria hyperborea – the kelp that they want to target – ‘Supports more life than the other kelp species in our waters’ (Schultze et al. 1990). Kelp is ‘a Key stone species’, it is the foundation of the food chain.
Why do we need our wild kelp beds?
Biodiversity supports our coastal fisheries and communities, it supports business. They are not two separate things. Biodiversity supports traditional shellfish and pelagic fisheries, wildlife watching, ecotourism, and marine based outdoor activity businesses.
Many of the animals that rely on kelp are commercially important and provide food for people. Food security is of vital importance, nothing should be done to jeopardize the ability of our coastal fishermen, shell fish farmers and divers to make a living whilst providing high value food for home and abroad.
The importance of kelp as a habitat is immense. To paraphrase Christy et al (2003); ‘From a study of the tiny life associated with L.Hyperborea in Norway, 238 species were found, with an average of 8000 individuals per plant, and a maximum of 80'000 individuals on one plant’. These thousands of invertebrates support fish, seals, otters, birds and us humans.
- 'Kelp forests are particularly effective nurseries for invertebrates and fish (e.g Atlantic cod and Pollock), which provide shelter from predation. Moreover, kelp forests are key feeding grounds for many NE Atlantic fish species, such as wrasse' (Smale et al. 2013).
- 'Kelps as primary producers and habitat providers play a key role in the maintenance of fish stocks and ecosystem structure, sustaining regional fisheries and the coastal communities they support' (Smale et al. 2013).
- ‘Elevated fish densities in kelp forests attract large piscivores, such as large fish, seals and otters. In general sub-tidal rocky reefs with extensive stands of L.hyperborea support greater species richness than reefs without high kelp coverage’ (Burrows. 2012).
- ‘In the N.E Atlantic, kelp forest habitats are vital for European lobster, velvet swimming crabs, and spider crabs’ (Smale et al 2013).
- 'The leisure and recreation industries directly reliant on coastal marine biodiversity contribute >£11 billion to the UK economy each year' (Beaumont et al. 2008).
Coastal erosion and rising sea levels.
Kelp absorbs carbon, buffers rising ocean acidity caused by climate change, and protects our coasts from erosion. Climate change is happening! Seas are getting rougher and more acidic; to remove anything that can ameliorate climate change is utterly bonkers. Many of our Scottish Islands are already experiencing increased coastal erosion.
- ‘Kelp forests prevent and alleviate the damage caused by flooding and storm events’ (Smale et al 2013). ‘Kelp forests alter water motion and provide a buffer against storm surges through wave dampening and attenuation and by reducing the velocity of breaking waves’ (Lovas and Torum. 2001), in doing so, ‘Kelp forests reduce coastal erosion and the movement of sand and pebbles from adjacent beaches’ (Mork 1996; Lovas and Torum 2001).
- ‘The removal of kelp is likely to result in ‘a relatively significant shift in the composition of the community and perhaps in the physical structure of the environment’ (Wilson, 1992).
What happens if we dredge it?
In countries where dredging for kelp is underway the devastating impacts on the environment and economy are only beginning to be understood. In areas of North America where the predators of the sea urchin have disappeared with the kelp, the urchin numbers have boomed and ‘over grazed’ preventing the reestablishment of the kelp forest.
- A recent study from Norway showed that ‘In newly harvested the number of small (<15 cm) gadid (cod, pollock, saith etc) fish was 92% lower than in un-harvested areas’ (Lorentsen et al 2010).
Marine Biopolymers say that they will leave it up to 5 years before returning to harvest areas of kelp, but a review of studies found that the biodiversity of a kelp forest is not regained even 6 years after trawling (Wilkinson, 1995).
The Scottish Governments ‘Wild Seaweed Harvesting Consultation’ from November 2017 (https://www.gov.scot/Publications/2016/11/6869/335422 makes the following points;
- In an assessment of benthic species' sensitivity to fishing disturbance, MacDonald et al. (1996) classified the kelp species L. hyperborea (mature) as having 'moderate' recovery potential.
- On the Isle of Man, studies by Hawkins & Harkin (1985) and Smith (1985) observed the effects of the removal of L. digitata and L. hyperborea. It was found that L. digitata re-grew whereas L. hyperborea did not (Kelly, 2005).
- Experimental work in Nova Scotia where Laminaria longicruris and L. digitata are harvested has shown that if kelp beds are destroyed and/or partially destroyed, grazing sea urchins may prevent regeneration and recruitment of climax kelp communities. It is thought that kelp harvesting removes the cover and protection of urchin predators (e.g. lobsters, crabs and fish) and this consequent reduction in predator pressure enables increases in urchin populations which then graze destructively on Laminaria, resulting in areas devoid of kelps (Bernstein et al., 1981; reviewed in Birkett et al., 1998). In Scotland, urchins do not tend to eat adult kelps but hinder re-establishment on cleared areas by grazing sporelings (Wilkinson, 1995). In addition, following harvesting in areas where there is an established population of urchins, the urchins can function as detritus feeders and remain at a sufficient level to inhibit kelp regeneration (Warner, 1984 cited in Wilkinson, 1995).
Kelp CAN BE FARMED. It is farmed in Norway, the Faeros and at Rathin Island between Ireland and Scotland. If alginate companies want kelp they must invest time in researching how they can make farming viable for them. Dredging the wild beds must never be an option.
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Beaumont, N. J., M. C. Austen, J.P. Atkins, D. Burdon, S. Degraer, T.P. Dentinho, et al. 2007. Identification, definition and qnantification of goods and services provided by marine biodiversity; implications for the ecosystem approach. Mar. Pollut. Bull. 56:386 – 396.
Birkett, D. A. Dring, J. & Savidge, G. 1998. Primary production estimates for phytoplankton, macroalgae and microphytobenthos in a coastal ecosystem. Abstractof talk given at annual meeting of British Phycological Society
Burrows, M.T. 2012 Influences of wave fetch, tidal flow and ocean colour on subtidal rocky communities. Mar. Ecol. Prog. Ser. 445; 193 – 207.
Christie, H., N. M. Jorgensen, K. M. Norderhaug, and E.Waage-Nielsen. 2003. Species distribution and habitat exploitation of fauna associated with kelp (Laminaria hyperborea) along the Norwegian coast. J. Mar. Biol. Asspc. U.K. 83:687 – 699
Lorentsen, S-H., Sjotun, K. Gremillet, D. 2010 Multi-trophic consequences of kelp harvest. Biological Conservation magazine.
Lovans, S.M. and A. Torum 2001. Effect of the kelp Laminaria huperborea upon sand dune erosion and water particle velocities. Coast. Eng. 44:37 – 63.
Mork, M. 1996 Wave attenuation due to bottom vegetation. Pp. 371 – 382 in J. Grue, B. Gjevik and J.E Weber, eds. Waves and nonlinear processes in hydrodynamics. Kluwer Academic Publishing, Oslo.
Schultze, K., Janke, K., Kruess, A. and Weidermann, W. (1990). The macrofauna and macroflora associated with Laminaria digitata and L. hyperborea at the island ofHelgoland (German Bight, North Sea). Helgolander Meeresuntersuchungen, 44: 39-51.
Sjøtun, K. and Lorentsen, S-H. (2003). Kelp forest (Laminaria hyperborea) as habitat for juvenile gadoids. Poster presented at the 3rd European Phycological Congress, Belfast, North-Ireland, 21-26 July, 2003.
Steneck, R. S., Graham, M. H., Bourque, B. J., Corbett, D., Erlandson, J. M., Estes, J.A. & Tegner, M. J. (2002). Kelp forest ecosystems: biodiversity, stability, resilience and future. Environmental Conservation, 29, 436-459.
Wilkinson, M. (1995). Information review on the impact of kelp harvesting. ScottishNatural Heritage Review No. 34. 54 pp.
Wilson, E. O. (1992). The Diversity of Life. Harvard University Press, US.