Researchers from Aberystwyth University have carried out the first ever environmental DNA (eDNA) assessment of marine vertebrates in Tristan da Cunha, a group of volcanic islands in the South Atlantic Ocean.

By matching tiny traces of eDNA found in the water to a global database of marine species, they have been able to reveal rare and vulnerable species – such as the ocean sunfish Mola mola – as well as provide important evidence to support conservation efforts in the islands.

The technique has also helped to identify other fish species more accurately than traditional survey methods used around Tristan de Cunha, the most remote inhabited islands in the world and one of the UK’s overseas territories.

Tristan da Cunha’s isolated location, over 2,000 kilometres from the nearest continental land, means regular assessment of its marine life can be challenging.

Dr Niall McKeown from Aberystwyth University, lead supervisor on the project, said: “Environmental DNA  – whereby DNA is shed into the environment by organisms – offers a powerful sampling tool which can help solve the logistical challenges associated with traditional survey methods and support sustainable, long-term assessments.

“This research is well timed given the recent designation of the islands as a Marine Protected Zone which will benefit from long-term ecosystem monitoring.”

The project was a collaborative effort between Aberystwyth University and the Tristan da Cunha Fisheries Department, as well as researchers from Queen’s University of Belfast and the University of KwaZulu-Natal.

Megan Elsmore, a doctoral student at Aberystwyth University’s Department of Life Sciences who led the research work and spent part of her childhood in Tristan da Cunha, said: “There is growing concern about the effects of climate change and human activities on marine life across the globe, with the biodiversity of remote oceanic islands like Tristan da Cunha particularly at risk. Traditional methods of monitoring and assessing – such as scuba diving or deep-water camera drops – can often be costly and time consuming.

“Environmental DNA offers a safer, easier, and more affordable solution to the need to monitor the biodiversity of the islands at a time when global extinction rates are alarmingly high.”

Places like Tristan are often those at the front line of the impacts of climate change. It is hoped that the research carried out in this study will help to strengthen conservation efforts around these islands which provide a “vital habitat for a range of commercially and ecologically important species.”

James Glass, director of the Tristan da Cunha Fisheries Department and supervisor to the project, said: “The importance of understanding the unique biodiversity of Tristan, and how eDNA techniques could enhance this understanding is vital, not just because of the incredible biodiversity that Tristan holds and protects, but because we are on the very front line of the consequences of climate change.”

The study’s findings have now been published in an academic paper in the peer-reviewed journal, Environmental DNA.

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