Towards an evidence-based Ascension Island Ocean Sanctuary

Written by Dr. Judith Brown, Director of Conservation and Fisheries, Ascension Island government

Squirrelfish form large shoals under the volcanic ledges of Ascension’s rich near-shore habitat. Photo by Dr. Judith Brown.

The U.K. government has taken a proactive approach to marine conservation, committing to marine protection around both its own shores and those of its overseas territories in what is known as its “Blue Belt” commitment. Whilst an honorable statement, now comes the hard work in determining what form that protection should take and how best to deliver marine reserves that really achieve notable conservation benefits to important marine biodiversity. On Ascension Island, a small but dedicated team of marine scientists has been working hard to gather the baseline data on inshore fisheries and biodiversity over the last few years, but their work is spreading to include all of the 200 nautical mile maritime zone – the waters that the Ascension Island government is responsible for managing. But gathering data in this larger and less accessible area is much harder and comes at great costs, with the need for a wider team of experts. Fortunately funding has been made available, not least by the U.K. government, to allow these scientific knowledge gaps to be addressed, alongside financing patrolling the waters in search of illegal vessels. Two external grants awarded by the EU Best Initiative and the U.K. government’s Darwin Initiative, combined with this ground-breaking National Geographic project, have enabled a dedicated trip to study the practically unknown seamounts that lie within Ascension’s waters. These areas were provisionally selected to fall within the zone closed to commercial fishing but they are in desperate need of research to justify if they really are the biological hotspots that we presume and therefore should be included in the final Ascension Island Ocean Sanctuary.

Ascension Island has the second-largest nesting population of green turtles in the Atlantic Ocean. Photo by Dr. Judith Brown.
Grouper are found inshore in super-abundant numbers. Photo by Dr. Judith Brown.

This current National Geographic Pristine Seas expedition has come at a critical time bringing together a core team of scientific experts from a diverse range of disciplines – from those who study the bottom of the food chain, the plankton, to the unique benthic communities, to the top level predators, the sharks. This biological research combined with the oceanographic data and the seabed mapping information allows the team to study the entire ecosystem – an opportunity very rarely brought together in one expedition. This research is addressing the key priorities in the Ascension Island governments scientific roadmap – a detailed plan of information needed to allow management decisions to be made based on scientific evidence. Whilst the data still needs processing we can see that the trip has been an enormous success and already we have witnessed what special habitats the Ascension seamounts are. New records (and very likely) new marine species have been discovered here and bioacoustic data have identified high levels of marine species abundance over the seamounts. Sharks are a species of particular interest due to their susceptibility as by-catch in commercial longline fisheries and here we have gathered unique footage of a not just a diverse range of shark species but evidence of high abundance of silky sharks. When in larger numbers sharks are often less cautious to approaching baited hooks, meaning that at these areas when the sharks are in greater abundance, they are likely to be more susceptible to being caught and a single longline could have a potentially devastating impact on the population found around the seamount. Bigeye and yellowfin tuna have also been seen and tagged during this project to investigate how long they stay around these undersea features and understand the importance of the seamounts to these species. All of this data, when reviewed and processed, will allow us to understand the seamount ecosystems and their wider importance within Ascension waters. However, already we can see they are sufficiently unique and rich in life to make them key candidates to fall within the Ascension Island Marine Protected Area.

A white striped cleaner shrimp cleans the mouth of a brown moray eel. Photo by Dr. Judith Brown.
A juvenile broad banded moray, one of many species of ell found in Ascension’s waters. Photo by Dr. Judith Brown.

Personally this voyage has been a fantastic opportunity – to get the chance to work with such enthusiastic and knowledgeable scientists alongside the hardworking and helpful crew of the two vessels is such a positive experience. The logistics to make such an expedition happen goes on unnoticed behind the scenes but was by no means an insignificant feat. The Ascension Island Government Conservation team extends a huge thank you to the National Geographic for making this trip possible and the scientists from the British Antarctic Survey, University of Windsor, University of Western Australia and University of Exeter, not to mention the amazing assistance from the captains and crew of the RRS James Clark Ross and Extractor.

Scarlet stripped cleaner shrimp stay hidden under ledges to avoid predators. Photo by Dr. Judith Brown.
The waters of Ascension have a huge abundance of fish including the brown chromis. Photo by Dr. Judith Brown.

The Pristine Seas team is currently conducting an expedition to the remote island of Ascension, in partnership with the Ascension Island Conservation Department, the British Antarctic Survey, the Royal Society for the Protection of Birds, and The Blue Marine Foundation.

Read all Ascension Island 2017 expedition posts.

Changing Planet


Meet the Author
Paul Rose is an ardent explorer, television presenter, journalist, author, and Vice President of the Royal Geographical Society, and an Expedition Leader on the Pristine Seas team.