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Mapping the future of sea life conservation

Using chemistry and cross-disciplinary expertise to protect ocean life

Published: 30 August 2017

Despite being Earth’s largest habitat, we still have so much more to discover about our oceans, and how to protect the species which depend on them.

Global warming, over fishing and offshore development are ever-growing threats to sea life, but researchers at Southampton are using chemistry and cross-disciplinary expertise to crack down on illegal fishing and improve seabird conservation in the North Sea and beyond.

The Common Fisheries Policy was published in 2014, introducing clearer labelling on seafood products to assist consumers with making more informed and sustainable choices when shopping. Since then, we have been able to see exactly where our fish is coming from.

However, illegal fishing remains a significant issue on a global scale. According to the Food and Agriculture Organization of the United Nations (FAO), Illegal, Unreported and Unregulated (IUU) fishing is responsible for catching around 26 million tonnes of fish a year. Not only is this a danger to fish stocks and the fishing trade, but it can also have a devastating effect on habitats and the environment.

In terms of seabird conservation, we need to know where animals are, especially in the North Sea. There are just so many wind farms, offshore developments and fisheries. It is a big priority to put the marine protection areas in the right places.

Katie St John Glew - Postgraduate research student within Ocean and Earth Science at the National Oceanography Centre Southampton (NOCS)

Using jellyfish to create chemical maps

Katie St John Glew, postgraduate research student within Ocean and Earth Science at the National Oceanography Centre Southampton (NOCS), is investigating the foraging behaviours of marine life. Using isotopes (variants of chemical elements) measured in jellyfish, she is making chemical maps of the UK shelf seas.

The chemical composition of tissues of different marine animals (or animal products) can then be compared to these maps to identify their most likely recent foraging and catch locations. This will allow her to identify where fish were caught across the shelf, helping organisations and fisheries to verify the catch locations of fish and manage stocks more easily.

Katie explains: “I have collected jellyfish from across the entire UK shelf sea while on fishery surveys, with help from the Centre for Environment, Fisheries and Aquaculture Science (Cefas), Marine Scotland, the Marine Institute and the French Research Institute for Exploitation of the Sea (Ifremer). I then measure the carbon and nitrogen isotope values in the jellyfish, and interpolate those values to make my maps.”

Once these maps – or isoscapes ­– are fully developed, scientists can collect isotopes from samples taken from seabirds and fish and compare the values to the reference isoscapes to learn more about their movements, habits and catch locations. Katie’s isoscapes are focusing primarily on the North Sea, and her team – including supervisor Dr Clive Trueman, Associate Professor in Marine Ecology – are the first to focus their attention on the UK shelf sea area.

We are using natural chemical signals to understand how animals move through the world’s oceans, and how energy and nutrients flow through marine food webs.

Dr Clive Trueman - Associate Professor in Marine Ecology

Saving our sea birds

Tracking sea life in this way will help us to understand more about the habits of birds including puffins, guillemots and razorbills from Scotland’s Isle of May. Little is known about these birds and their movements during the winter. Although they breed on land in the summer months, in winter they fly out to sea to moult and regrow their feathers, leaving them vulnerable. Declines in their numbers means tracking and mapping their movements is ever more important.

By assessing the isotopes in their feathers upon their return, scientists can find out where they were feeding during the winter, therefore understanding more about their movements and how best to move forward with conservation.

“If we know where they are during their most vulnerable months, and what they are feeding on then, hopefully, they can be better understood and protected,” says Katie.

“In terms of seabird conservation, we need to know where animals are, especially in the North Sea. There are just so many wind farms, offshore developments and fisheries. It is a big priority to put the marine protection areas in the right places.”

Sustainable fishing and the revival of North Sea cod

The North Sea is not just a primary focus for seabird conservation. In July 2017 it was announced that North Sea cod is recovering from overfishing, after being under threat for more than a decade.

The techniques being created and used by Katie and her team are becoming more important now that the North Sea is being opened up again for cod fishing, and with the potential legislation and trade changes that Brexit may bring.

Using isoscapes to assess the catch location of fish was a focus for Katie in her presentation for the University’s Three Minute Thesis (3MT) final. Ensuring that fish are being caught legally and sustainably is as much about maintaining trust as it is about being an environmentally-conscious consumer.

“We will be able to tell the difference between Norwegian-caught cod, Iceland-caught cod and North Sea-caught cod. If it says North Sea cod, we need to be able to verify that it is correct, so that people are confident in what they are buying.” Katie says.

Clive Trueman adds: “Katie’s work is part of a larger research focus here at the University of Southampton Ocean and Earth Science, where we are using natural chemical signals to understand how animals move through the world’s oceans, and how energy and nutrients flow through marine food webs. 

“Katie’s work is particularly exciting as her results have immediate practical applications for conservationists, fishers and consumers.”

Katie won the Joint Runner Up and People’s Choice prizes in this year’s Three Minute Thesis (3MT®) Grand Final at the University. Watch her presentation, outlining her research, below.

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