Underwater cameras around the Isles of Scilly have given scientists a glimpse of how sea life can thrive in well-protected UK waters, adding clout to the argument for a blanket-ban of bottom-trawling in marine protected areas – a call that was rejected by MPs last week.

Despite widespread degradation of UK seas from destructive fishing practices like bottom-trawling and dredging, pollution, and climate change; the waters surrounding the Isles of Scilly appear to be bucking the trend.

These are the observations made by researchers at the University of Exeter who used baited underwater cameras to find that waters around the Isles of Scilly support vibrant marine life including sharks, lobsters, octopuses, and bluefin tuna.

Those same scientists say the relatively low-cost camera systems used in this study ‘could be used to improve the monitoring and effectiveness of Marine Protected Areas (MPAs) around the UK – helping to restore thriving seas around the country.

To conduct the study, researchers at the University of Exeter partnered with the Isles of Scilly Inshore Fisheries and Conservation Authority as well as Natural England. 

“The richness and variety of marine life around the Isle of Scilly is wonderful to see,” said Dr Owen Exeter, from the Centre of Ecology and Conservation on Exeter’s Penryn Campus in Cornwall. “Our cameras recorded nearly 12,000 individual animals from 64 species, including large populations of commercially targeted species such as lobsters and small sharks.

“We also saw bluefin tuna – which have recently returned to UK waters after largely disappearing due to overfishing.”

While the site in question isn’t entirely untouched by human activity, the team describes it as one of the UK’s most ‘near-natural’ marine ecosystems; largely protected from destructive practices such as bottom-trawling, and with relatively low human impact due to the archipelago’s small population and well-managed fisheries.

“These waters haven’t recovered from severe damage – they’ve remained in comparatively good condition. But, studying ecosystems like this means we can start to understand what a healthy UK marine environment should look like,” continued Dr Exeter. “This gives us a crucial reference point as we work to restore degraded areas elsewhere.”

The findings suggest that complex seabed habitats, such as reefs and mixed sediments which can be damaged by bottom trawling, host especially high biodiversity, underlining the importance of protecting these areas.

Bottom trawling – a focus of the recent David Attenborough film, Ocean – is currently permitted in a good number of UK Marine Protected Areas. The government stated earlier this year it would move to ban the practice from 41 marine protected areas in English waters but last week rejected calls to implement a blanket-ban on bottom-trawling in all protected areas.

“MPAs are only as effective as the protections and monitoring in place to support them,” said Dr Kristian Metcalfe, associate professor in Marine Conservation Science at the University of Exeter, who has argued that the Baited Remote Underwater Video Systems offer a “powerful tool” for assessing whether marine protected areas are delivering measurable benefits for marine biodiversity when bottom trawling is excluded.

“These camera systems allow us to track changes in species diversity and abundance over time, giving us vital evidence on whether conservation measures are working,” said Dr Metcalfe. “They’re non-destructive, relatively inexpensive, and scalable – making them a great option for regular biodiversity assessments across large areas of our coastal seas.”

The research has now informed the designation of the Isles of Scilly as an Important Shark and Ray Area (ISRA), a recognition that highlights the region’s significance for four shark species (primarily catsharks, with supporting species nursehounds, blue sharks, and porbeagle sharks) and provides an important tool to guide conservation and management efforts locally.

ISRAs are not regulatory or restrictive, but rather reflect areas of ecological interest and serve as a science-based framework to inform decision-making and strengthen the case for future funding and conservation initiatives.

The paper, published in the journal Ecological Applications is entitled ‘Application of spatially robust stereo baited remote underwater video sampling for quantifying fish assemblages in UK marine Protected areas.’ It was funded by a Natural Environment Research Council GW4+ Doctoral Training Partnership PhD Studentship – a case partnership between the Isles of Scilly Inshore Fisheries and Conservation Authority and Natural England.

Click here for more from the Oceanographic Newsroom.