Proposals to dredge Scottish kelp forests would be conservation calamity

By: Clare Fischer
Date posted: 24 August 2018

Kelp forests in Scotland are facing threats on two fronts.

Kelp
© SNH / Richard Shucksmith

Mechanically stripping swathes of pristine kelp forest clean from the reef at the scale proposed simply cannot be considered sustainable

Calum Duncan,
MCS Head of Conservation, Scotland

An application has been lodged to mechanically dredge areas of kelp by pulling whole plants from the sea floor. Coincidentally, new research suggests warming waters will affect kelp to the extent that species that thrive in warmer seas will change the dynamics of the quantity, quality and availability of food affecting other species likes crabs and lobsters around the UK’s coast.

Marine Biopolymers want a licence to be granted, allowing them to pull kelp plants from the sea bed.

The dredging proposal is ill-judged according to MCS Head of Conservation in Scotland, Calum Duncan: “We are extremely concerned about this flawed proposal. 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, including crabs, lobsters and the young of commercial fish. Kelp habitats are a priority marine feature in Scotland’s seas and it is a requirement of the National Marine Plan that their national status must not be significantly impacted, which this proposal would risk doing.”

Marine Biopolymers have outlined their plans in a report which the public had until August 24th to comment on. It said the company planned to harvest up to 34,000 tonnes of kelp per year, that’s about 0.15% of all the kelp in Scotland. Their proposed sustainability measures include plans to avoid harvesting young kelp, and to leave harvested beds alone for five years to recover.

The UK currently has no large-scale harvesting of wild seaweed or kelp forests, but in Scotland there are businesses harvesting seaweed on a small scale. Strict rules apply to hand harvesting which includes recording every single invertebrate bycatch. Small- scale harvesters are concerned that there could one rule for them and one for operators allowed to dredge.

Calum Duncan added: “Sustainable hand-gathering of kelp has very careful measures in place that require the base to remain attached to the reef. Mechanically stripping swathes of pristine kelp forest clean from the reef at the scale proposed simply cannot be considered sustainable. We would urge a complete re-think and lower impact alternatives, such as managed hand-gathering and seaweed culture, to be explored instead.”

Elsewhere a research team has studied the ecosystem consequences of an expanding warm-water kelp species, Laminaria ochroleuca, which is proliferating under climate change. Lead author Albert Pessarrodona says as the ocean warms, species are “moving up slopes and towards the poles in order to remain within their preferred environmental conditions. Species with warm affinities are migrating to many habitats previously dominated by cold-water ones, transforming ecosystems as we know them. These so-called novel ecosystems feature a mix of warm- and cold-affinity species, but we don’t know whether they can retain desirable ecological processes and functions which human well-being relies on”.

The scientists studied kelp forests in the southwest of the UK, where the warm water kelp species has increased in recent years – probably at the expense of cold-water species, which are less tolerant to warming seas.

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Did you know?…

MCS established its Scotland office and programme in 2000 in Edinburgh

Scotland has 10% of Europe’s coastline

Over the last century, we have lost around 90% of the biggest predatory oceanic fish, such as tuna, swordfish and sharks