It’s been ten years since the University of Plymouth began its landmark assessment of the Marine Protected Area (MPA) at Lyme Bay, off the coast of Devon and Dorset: a decade of research and observation into how the natural environment recovers from the effects of commercial bottom towed fishing.
Through changing seasons, Dr Emma Sheehan has come to develop a special regard for the 200 sq km site, whose mud stone reefs shelter important fish and crustacean species. Whether surveying the sea state from the deck of the boat, or peering through the portal of video footage revealing the underwater life below, Emma now has an innate sense of the rhythms of the marine reserve.
“I love the fact that I have a good mental map of the sea bed, and it’s amazing to see how the different parts of the bay change each year,”
“I don’t think I was aware that I had such a personal connection to the place until we went to record the impact of the storms on the seabed in 2013/14. It was extreme, and I found myself getting quite emotional as areas of the seabed that had started to flourish had been scoured and covered by the sand washed in by the storms.”
Commissioned by Defra and Natural England, Emma, Professor Martin Attrill, and a host of students and research assistants have monitored the return to life of the reef after years of bottom towed fishing. By ‘flying’ a towed high-definition camera above the seabed, they have been able to paint a picture that is informing management and monitoring strategies for future MPAs in the UK and other temperate regions.
One of the most important discoveries to emerge from Lyme Bay is the role that sandy areas play in providing key habitats for species. As contained in their paper 'Drawing Lines at the Sand', the sand and gravel beds within MPAs are often not covered by EU legislation – with protected status usually confined to the rocks and reefs that boast very visual populations of marine life.
“It is something of an ‘inconvenient discovery’ for many that these inter-reef areas are not only important to animals, such as crabs and lobsters, who bury themselves in it, but also provide habitat for sessile, habitat building, typically reef associated species, such as sponges and sea fans,” Emma says.
“When we first began taking video transects in 2008, these sessile reef-associated species simply weren’t there. But by 2011, the increased abundance of these species, suggested that these sandy areas were in fact sediment veneers on rock, indicating that the reefs extend much further than previously thought”.
So the video is like a time machine, and who knows what might develop in the future that we cannot see today.”
Emma’s long association with the University of Plymouth officially began in 1998, when she enrolled as an undergraduate on the marine biology and coastal ecology degree. But her connection to the institution really began at a much earlier age.
“My father will tell you that I’ve been coming to the University to study marine biology since the age of five,” she says, laughing at the memory. “I didn’t even know what a marine biologist was, of course, but I knew that I wanted to study whales and dolphins. After my A levels, I took a year out and went to Australia, and the prospect of my degree was the only reason I came back.”
By her own admission, Emma threw herself into university life with plenty of relish, and it was only a return trip to Australia, for her honours project on marine ecology statistics in Sydney, that she "got back on it" and focused her energies on securing a first-class honours degree.
Her first job was with the Atlantic Whale Foundation in Tenerife, where she trained whale-watching eco-volunteers, before moving to Falmouth to work for Natural England as an Assistant Marine Conservation Officer with a remit for the Isles of Scilly. Emma knew, however, that she needed a postgraduate qualification if she were to progress in her career, and within months had successfully applied for a PhD at the University, working with supervisors Professor Martin Attrill and Professor Richard Thompson on the impact of ‘crab tiling’ on estuarine ecosystems in Devon and Cornwall.
This segued into a role as a post-doctoral Research Fellow in the Marine Institute, working under Professor Attrill. Initially funded by the then South West Regional Development Agency, Emma developed the equipment needed to monitor the impact of Wave Hub in Cornwall and commenced annual surveys of the site. Then, in 2008, working with a cast of researchers from Plymouth Marine Laboratory, the Marine Biological Association, and others from the University including Professor Attrill, Professor Jason Hall-Spencer, Dr Lynda Rodwell, Dr Sian Rees and Dr Kerry Howell, Emma helped to submit the tender to monitor the ecological and socioeconomic effects of excluding bottom towed fishing in Lyme Bay.
“There is a significant amount of off-shore working on fishing boats,” she says of her fieldwork. “And I make a moral choice to use local fishermen wherever I can, because I want to involve those people who are so often impacted by decisions taken at government level. And when we send down our cameras they are often amazed by what they see – one fisherman in Hayle, Cornwall, thought there were crabs everywhere, avoiding his pots, and was surprised to discover it wasn’t the case.”
This fragile balance in the natural environment can easily be tipped by anthropogenic stressors, and it’s not just the direct effects of commercial fishing that are responsible.
In a 2017 paper published in Biological Conservation, Emma and co-investigator Professor Hall-Spencer, presented evidence that ‘ghost fishing’, a consequence of lost fishing gear harming marine life, typically associated with whale and bird mortality, was also responsible for damaging coral reef gardens. This was particularly evident when hundreds of ‘sea fangles’ were washed up on beaches across the South West, which, under examination in the laboratory, were found to contain dead pink sea fans and an assortment of plastic rubbish, from fishing line to tights, balloons to headphones.
“Pink sea fans make an important contribution to biodiversity, so this phenomenon is concerning,” Emma says. “This accumulation of plastic debris, from lost fishing gear to domestic waste, is manifesting in many different areas, and it’s vital that we work to tackle this issue at both a policy and individual level.”
Recently made a Senior Research Fellow in recognition of the work and team she has built, Emma’s latest project concerns another important species – sea bass – and promises to be one of her most innovative to date. With a grant from the European Marine Fisheries Fund, she is monitoring the movements of juvenile bass in and around a number of Devon estuaries, using a system of tagging.
“Sea bass are protected due to a sudden crash in their population,” she says. “They are an important and iconic species, renowned for being hard to catch, so we are working with a range of people to catch around 150 so that they can be tagged and released.”
With PhD student Tom Stamp, who is funded by the Association of Inshore Fisheries and Conservation Authorities, the pair are using arrays of mobile transceivers to record the ‘pings’ of the fish as they move around – and possibly outside – the protected environs of their nursery. The enormous potential for the project has been highlighted by enquiries from the Centre for Environment, Fisheries and Aquaculture Science, the Environment Agency, and the University of Exeter, looking to use the system to monitor other species in the area such as tuna and gilt-head bream.
“Technology enables us to peer beneath the surface and see what is happening in our marine environments,” she adds. “But there’s still no substitute to getting out there, in the field, and experiencing those changes for yourself.”