A squid in a dark room with a UV light shining on it with spots all over its body glowing red

This jewel squid is one of many species found in the seas around St Helena and Ascension Island.

 © Chris Fletcher

Creatures from the deep: exploring the seas around remote South Atlantic islands

The islands of St Helena and Ascension are among the remotest places on Earth, located almost two thousand kilometres from the nearest landmass.

Museum scientists joined a six-week voyage to understand more about the fragile and rarely studied environments surrounding these islands.

RRS Discovery docked at a port

The RRS Discovery carried a team of scientists over 9,000 miles to survey some of the remotest marine environments on the planet.

 © James Maclaine

In October 2022, the RRS Discovery set sail from Southampton on a 9,000-mile expedition to survey some of the remotest marine environments on the planet.

On board were a team of scientists equipped to sample and map the sea floor, test water quality, measure temperature and plastic particles, and identify the species living in the remote waters of the South Atlantic.

The expedition is part of the UK government's Blue Belt Programme, which works closely with UK Overseas Territories to assist them in managing and maintaining healthy and productive marine environments.

The programme works closely with eight UK Overseas Territories, which include Ascension Island, St Helena, Tristan da Cunha, South Georgia & the South Sandwich Islands, British Antarctic Territory, Pitcairn Islands, British Indian Ocean Territory and the Turks & Caicos. Combined, their Marine Protected Areas span 4.3 million square kilometres of ocean. 

Museum scientists Chris Fletcher and James Maclaine joined the expedition providing their expertise in collecting and identifying specimens while taking tissue samples of fish and invertebrates for molecular analysis.

The expedition was initially scheduled for the end of 2021. But even after two-weeks isolation on board the ship, some crew, including the captain, caught COVID-19 and the trip was postponed for a year.

A juvenile footballfish

A juvenile female footballfish, a type of anglerfish. The white spots on its body are sensory organs that help it detect prey.

 © Chris Fletcher

Pelecan eel and Fangtooth

The pelican eel (top) and fangtooth (bottom) have large mouths and teeth to take advantage of the scarce amount of prey they come across.

 © James Maclaine

Chris, a research assistant specialising in marine invertebrates, says, 'Before this trip, I hadn't really done a big research cruise before. I've mainly just been on fisherman's boats around the UK coast. But this was on a big ship and going to a place I'd never been.'

‘It was incredible. I wasn't going to miss out.'

RRS Discovery bears the same name as the first Royal Research Ship that was used by Captain Robert Falcon Scott and Ernest Shackleton during their 1901-1904 expedition to the Antarctic.

Crew members on deck a night holding cabels ready for the net to be pulled up

Crew members wait on deck with anticipation as the nets are hauled in.

 © James Maclaine

It initially set out from Southampton, stopping in Cape Verde to pick up some of the research team including Chris and James, before setting a course for the South Atlantic.

Discoveries from the deep 

The team aboard the ship worked 24 hours a day throughout most of the sampling periods.  

During the day, teams would analyse the seabed, including sampling the sea floor thousands of metres below the surface, but during the night, Chris and James would get to work.

James, Senior Curator of fish at the Museum, says, 'My job was to help with the pelagic trawls, which sample the midwater region between 200-1000m'

'Most of the really interesting animals go deeper in the day and then move up when it gets dark to avoid predators, so we had to work through the night.'

'Chris and I were there for when the nets came in, going through the samples, sorting them and trying to identify as much as we could to get an idea of the biodiversity. It was great to see specimens that were fresh out of the sea.'

A viperfish under UV light showing its large eye glowing an empermeral blue and red dots along its mouth and side.

A close-up of Sloane's Viperfish under UV light.

 © James Maclaine

A loosejaw fish showing a comma-shape red glowing organ under its eye.

The stoplight loosejaw has two light-producing organs under the eye, one green and the other red, which help it to see and attack prey.

 © James Maclaine

The team used a trawl with two nets to sample specimens at two different depths.

First, the gear would descend to a depth of up to 1000 metres, then one net would open and trawl for about 40 minutes before closing. It was then brought up to a shallower depth of 400-700 metres, and the second net would open. 

The specimens are yet to be thoroughly analysed, but some surprising discoveries have been made already.

A fish under UV light, showing paired red light running down its belly.

The light organs on a lightfish glowing red under UV light.

 © James Maclaine

'We used a UV pen to see if any of the animal's photophores lit up, and this jewel squid just lit up beautifully with red,' explains Chris. 'Usually, deep sea photophores glow blue, which is better for communication because red light gets absorbed easily by water.'

'It's really bizarre, but I don't think there's any function to it because these animals wouldn’t want their lights to glow red,' James adds.

'I think it's just to do with the chemicals in the light organs, but it's really spectacular.'

When asked if they may have found anything new to science, James says, 'It's totally possible, but will take a bit of investigation. The problem is that it's hard to say if something is new or if it's just a baby version of something else because quite often things change quite dramatically as they develop.'

'But one of the most exciting fish we found was a juvenile anglerfish which has strange filaments on the stem of its lure. And that means it's either a new species or a species only previously known from six specimens. So that's really exciting.'

The photophores on a Sloane's viperfish glow red under a UV light.

The Sloane's viperfish was one of a few animals that glow red under UV light, which may be a result of chemicals in the light organs.

 © Chris Fletcher

Conserving islands

Saint Helena and Ascension Island lie south of the equator between Africa and South America. They each house a small population with an economy mostly dependent on fishing.

Sitting almost 1,300 kilometres apart, these two UK Overseas Territories also manage two large scale Marine Protected Areas (MPA), which cover over 890,000 square kilometres of ocean – an area similar in size to the whole of Pakistan.

A galapagos shark interacting with a camera on a pole

This Galapagos shark took an interest in the baited underwater video system, which is used to see what large marine predators were in the area.

 © Shona Murray

Expeditions such as RRS Discovery provide the equipment and expertise to help support these islands and survey the surrounding areas to help better protect them.

'It’s so that the waters around these British Overseas Territories can be managed better,' says James.

'There's the nice example of Tristan da Cunha, which now has a huge protected area around the islands. So, if you want to fish or sample there, it's a lot more regulated, and that was a direct result of the kind of work we are doing.'

'It's all evidence to say an area is important and fragile and needs to be regulated and managed properly. You can't properly manage an area if you know nothing about it.'

The expedition has made some new and exciting discoveries, including two previously unknown mountain ranges under the sea, known as seamounts.

Shallow underwater cameras unearthed huge populations of Galapagos sharks, which is a good indicator of a healthy marine ecosystem. Deep-water cameras also found large cold-water coral reefs at a depth of 1,000 metres. These reefs contained species like black coral which can live for up to 4000 years, making it one of the oldest living animals on Earth.

A small baby anglerfish with its mouth open on a petri dish

This juvenile black seadevil anglerfish is no bigger than a pea. The little black dot between her eyes is her luminous lure.

 © James Maclaine

A small semi-transparent squid lying on a petri dish

Most of the specimens found in the nets were fairly small, such as this two-finned squid.

 © James Maclaine

Ascension Island and St Helena have permitted samples to be brought to the Museum to make them more accessible for global research.

The team are now waiting for the ship to return to the UK later this year with more of the specimens and tissue samples they collected to be studied in-depth by Museum scientists.

Jonathan the giant tortoise standing on the grass

Jonathan, the 190-year-old Seychelles giant tortoise who lives on St Helena.

 © James Maclaine

When the boat reached each island, Chris and James got the chance to explore these isolated lands. On Ascension, they spoke to local schools about the importance of the work they were doing and hiked up a mountain to see land crabs. 

On St Helena, they got to meet Jonathan the Seychelles giant tortoise as he turned the ripe old age of 190, making him the oldest known living land animal.

Reflecting on the trip, Chris says, 'It's a lot of hard work and a lot of night shifts. You're tired most of the time and forget what it is to be fully awake, but you survive it because everything is just so interesting.'

'That excitement of seeing what the nets have brought up is my absolute favourite moment,' James adds.

'These experiences don't come around very often, so it's such a privilege, and I'm very grateful for being invited. To be there collecting these samples and seeing things for the first time alongside people making all these new discoveries. It's one of the best parts of my job.'