Protect the kelp forests

An Ayr-based company called Marine Biopolymers (MBL) is now seeking a licence from Marine Scotland to take kelp from the Scottish seabed using a large mechanical arm. MBL commercially extracts polymers from seaweed for use in industries including food and pharmaceuticals.

Their dredging method would harvest seaweed using a mechanical comb, measuring between three and four metres to trawl the seabed. This method removes entire kelp plants, with the idea that juvenile plants are left to promote more rapid recovery. MBL claims that over five years it will start harvesting 30,000 tonnes per year of the seaweed Laminaria hyperborea, a large, leathery brown kelp.

Researchers in Norway have investigated the effects of kelp dredging on commercially important species, and found 90% fewer young fish in harvested areas. Scottish Natural Heritage suggests that Scottish kelp holdfasts typically house between 30 and 70 different species, including worms, molluscs and anemones. In turn, these animals provide food for fish and mammals like seals and otters. 

Existing Scottish kelp harvesting is limited to hand-cutting fronds, and ensuring that the stems and holdfasts (the part of the plant that connects to the seabed) are left intact. The new proposed dredging method will rip up entire kelp plants, including their holdfasts. Kelp dredging will also lead to a reduction of genetic diversity making kelp forests more susceptible to potential diseases and climate change.

Sir David Attenborough explained,  'These kelp forests - which can be found right here, around the coast of the British Isles - not only form an important part of the food chain, but also act as a vital habitat for a wide array of species. Their thick foliage offers food and safety from predators, and provides a nursery ground where juvenile fish can mature in safety. Look closely among the intricate stems and fronds of kelp, and you will find a range of fascinating sea life, from invertebrates such as sea stars, anemones and limpets, to mammals such as sea otters. Many of the fish species, such as cod, that are so important to us economically and culturally are also found here. For these reasons and many more (carbon storage being just one), it is absolutely imperative that we protect our kelp forests. It is perfectly possible to harvest them sustainably by removing their fronds while leaving the rest of the plant intact. But dredging - or indeed any kind of harvesting that removes the whole plant - is a wholly short-sighted measure that risks the wholesale devastation of our kelp beds. I urge decision makers to take the necessary action to protect these vital, and globally important, habitats.'

http://www.nhm.ac.uk/discover/news/2018/october/kelp-dredging-in-scotland-would-be-a-disaster.html