New research shows bottom trawling during scampi fishing can disturb carbon buried in seabed muds for thousands of years
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A new study has revealed how crustacean fishing – including that of Norway lobster, which is used to make scampi – could be driving a ‘largely invisible’ climate cost in the North Sea. Essentially, the process could disturb carbon that has been buried in the seabed for thousands of years.
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Researchers at the University of Exeter examined carbon levels of the seabed of Fladen Ground – a large seabed east of Scotland, which is one of the North Sea’s most commercially important fishing grounds. These muddy seabeds are also important long-term carbon stores, which are vital for climate regulation.
When fishing occurs – usually via bottom trawling, a process by which nets are dragged across sea floor habitats – sediment is churned up and carbon levels cannot replenish themselves quickly. Researchers also stress that ancient stores are likely to be affected.
While scampi is often marketed as a sustainable seafood choice, many people don’t realise that catching Norway lobsters involves towing nets directly across the seabed. That makes the environmental cost of scampi largely invisible to consumers.
The study argues that effective marine management should consider not only how much carbon is stored in seabed sediments, but how quickly it is being buried and how vulnerable it is to being released.
‘For fisheries to be genuinely sustainable, we have to consider where fishing takes place and how different seabed habitats function in the carbon cycle,’ said co-author of the study Professor Callum Roberts. ‘This isn’t an argument against eating scampi or against fishing itself. But if seafood is to be climate-smart, we need to think not just about what we catch, but how and where we catch it, and use smarter spatial management to avoid disturbing seabeds that are actively accumulating and efficiently burying more vulnerable carbon.’
Is bottom trawling bad for the environment?
In short, yes. The method is popular with commercial fishing companies, precisely because it makes it easy to catch large quantities of fish in one go. However, it also damages the seafloor, releasing carbon and killing non-target marine life – like coral, seals, dolphins and seabirds.
Bottom trawling is responsible for more than a quarter of all global catch, and targets a huge variety of wild species both for human consumption and for making feed for farmed animals.
Latest figures show that 522 seabirds (including albatross) and 152 mammals (including fur seals and dolphins) were killed by bottom trawling across a 12-month period.
