Marine Protected Areas at risk
5 minute read
Effective management of the UK's network of Marine Protected Areas is vital to allow our seas to recover. Unfortunately, some of our largest protected areas still permit damaging fishing practices, like bottom trawling.
South West Approaches to the Bristol Channel
Why is it protected?
Located off the northern coast of Cornwall, the seabed in the South West Approaches to the Bristol Channel is made up of a range of fine sediments, coarser sediments, shell fragments, gravels, shingles and cobbles. These habitats provide a home for diverse species that bury into the seabed, including worms, razor clams, anemones, sea cucumbers and sea urchins.
Why is it at risk?
Bottom trawling in this area has occurred for years and has impacted seabed life. Filter feeding organisms that keep the water clean, such as sponges and bivalves, are reduced by the dragging of fishing gear across the seabed. Churning up the sediment also releases stored carbon back into the water.
What does recovery look like?
- Increasing numbers of mussels (blue mussels, horse mussels and fan mussels) and sponges that are important as filter feeders (e.g. Cliona).
- Delicate biodiversity such as pink seafans would also be allowed to grow (they reach maximum size at about 30 years of age).
- The important colonial Pentapora foliosa would also be allowed to grow, providing a habitat for many small lifeforms.
- The richness of the seabed would become a more favourable ground for juvenile fish.
Damaged reef
Credit: Colin Munro Photography
North Norfolk Sandbanks and Saturn Reef
Why is it important?
About 40 km off the coast of Norfolk, the North Norfolk Sandbanks are the most extensive example of offshore linear ridge sandbanks in the UK. The banks support communities of invertebrates typical of sandy sediments, such as polychaete worms, isopods, crabs and starfish.
Areas of Sabellaria spinulosa biogenic (living) reef are present here, consisting of thousands of fragile sand-tubes made by ross worms (polychaetes) which together create solid structures rising above the seabed.
The area overlaps with the Southern North Sea Special Area of Conservation, which has also been identified for the protection of harbour porpoise.
Why is it at risk?
The area has been subjected to substantial levels of harmful fishing, including electric pulse trawling, beam trawling and otter trawling.
Electric pulse trawling involves applying an electric current to the water, causing fish to involuntarily swim towards it. This method of fishing – banned in the UK since leaving the EU, but still continuing in EU waters – has damaged all parts of the ecosystem. The voltage doesn’t just harm the fish, but other parts of the food chain too.
The site currently allows unlimited beam trawling, using industrial nets weighted down by heavy beams dragged across the seafloor. Otter trawling can also impact fish numbers if juveniles are caught, as this means species are collected before they have a chance to breed.
Tearing up the seabed also affects the food chain, as reefs of mussels and rich communities of filter-feeding sponges and corals are destroyed, leaving only worms and buried bivalves behind.
What does recovery look like?
- Prevention of trawling will allow the ‘troughs’ between the sandbanks to accumulate life, such as small coral, hydroid, bryozoan and sponge communities.
- The seabed will then be allowed to grow rich Sabllearia worm reefs that can grow up to 60 cm above the seabed.
- This complexity of life will attract greater numbers of flatfish for feeding.
- The area could support large species such as angelshark, common skate and halibut. These fish have been effectively wiped out from UK seas by industrial fishing. When caught, they are so rare that they make the papers.
Harbour porpoise
Credit: Richard Shucksmith / scotlandbigpicture.com
South-West Deeps (East)
Why is it important?
This is a large conservation area in UK deep continental shelf waters, about 190 km southwest of the Land’s End peninsula. The area experiences a great summer plankton bloom which enriches the waters, leading to concentrations of plankton. These support groups of whales, seabirds, basking sharks, anchovies, sardines and other species.
On the seafloor, life ranges from sponge and coral beds, to large bivalves called ‘fan mussels’ as large as a dinner plate.
Why is it at risk?
The natural balance of the habitat and the species that live there have been gravely affected by decades of industrial fishing.
The dominant fishing is from pelagic fishing fleets and long-liners that target large fish near the surface. However, the beam trawling that takes place here erodes, uproots and crashes into species that are damaged by physical contact.
For thousands of years, these species have evolved to grow slowly in a relatively stable environment and cannot withstand the destructive effect of seabed trawls.
What does recovery look like?
- Beds of corals, sponges, delicate hydroids and bryozoans will accumulate.
- This garden of richness will support other forms of life such as rarely encountered sharks (e.g. sixgill shark), molluscs such as strange octopus and squid.
- The number of deep-water fish species could recover and grow to larger sizes.
- Species that were once abundant, such as angel shark and North Atlantic halibut, would be properly protected in a large area.
Fan mussels, which can grow up to 48cm, were once ubiquitous on the South-West Deeps seabed
Credit: first atrina / Sally Sharrock
Offshore Brighton
Why is it important?
Offshore Brighton is in the deep waters of the English Channel, approximately 45 km south of Selsey Bill, West Sussex. The seabed is predominantly coarse sands and gravel with areas of exposed bedrock and mixed sediments.
Diverse species live here including burying animals such as worms, sea anemones and bivalves. Hydroids, bryozoans and sponges colonise the boulders and cobbles, where hermit crabs and starfish thrive. During the spring and summer months, large numbers of bass and black sea bream migrate and feed in shallower waters. Many of these species are targeted by bottom trawls.
Healthy gravel beds are also used by herring to lay eggs. Trawling these fish and eggs up from the seabed doesn’t allow our seas to reach their potential.
Why is it at risk?
Bordering French waters, Offshore Brighton experiences the highest industrial fishing density of any Marine Protected Area.
UK, French and Belgian fleets use demersal seining, a method of fishing that uses vast ropes and nets to herd in huge schools of fish on the seabed. The ropes are weighted with metal to drag along the seabed and can be up to 4 km in length. They are slowly winched towards a net that then is tightened around the fish.
In February 2021, Greenpeace dropped boulders here to create an underwater barrier in protest of the lack of restrictions on bottom towed fishing. They have also stopped certain types of fishing activity (e.g. demersal seining) by approaching the vessels in a small boat.
What does recovery look like?
- Recovery could see rich collections of sand-associated species such as flatfish (sole is a very profitable catch), gurnard, red mullet, skates and rays and sharks.
- An impressive array of marine life, such as corals, sponges, bryozoans and hydroids, would also be allowed to grow and breed, leading to richer, more complex forests of life.
- Protecting these rich sediment areas will mean looking after important staging grounds for small and juvenile fish, such as herring.
Common starfish
Credit: Paul Naylor