Ascension Island Government (AIG) has spent much time considering the best way to manage its marine environment, taking into account the need to protect marine biodiversity alongside the economic driver to generate much-needed income for the Island. A licensed, foreign-flagged, commercial longline fishery for tuna operated in the waters around Ascension Island from 1988-2004 and then again from 2010-2013, with license fees contributing a significant portion to annual Government revenue. In 2014, AIG suspended the fishery whilst they reviewed and updated fisheries legislation and licensing criteria.
In December 2015 the commercial fishery re-opened in 50% of the Exclusive Fishing Zone (EFZ), with the remaining 50% of the zone closed to commercial fishing. This formed the first step in the UK Government realising its manifesto commitment to designate a large-scale marine reserve covering at least 50% of Ascension Island’s 440,000 km2 Exclusive Economic Zone by 2019. Once designated, the “Ascension Island Ocean Sanctuary” is set to become the largest fully-no-take Marine Protected Area (MPA) in the Atlantic Ocean. Critical knowledge gaps need to be addressed in order to identify those areas that would benefit most from spatial or temporal protection measures, and to allow the success of these measures to be evaluated. For this reason, AIG deferred formal designation of MPAs while existing scientific data was compiled and analysed and new research took place to enable informed decisions on the placement of Marine Reserves.
Description of the project
The project represents the first detailed ecological study of Ascension Island’s three shallow-water seamounts to feed into a major marine spatial planning exercise that is currently being led by AIGCFD, with the intention of designating the Atlantic Ocean’s largest no-take MPA (or MPA network). Progress towards this goal is already well advanced in inshore areas.
Using an innovative combination of aquatic telemetry and underwater video census techniques, the project would assess the importance of Ascension’s seamounts as aggregation areas for pelagic megafauna and determine the size of marine reserves needed to effectively protect such assemblages from the impacts of commercial fisheries.
The principle scientific expedition to Ascension Island’s outlying seamounts took place between 19th May and 4th June 2017 and proved to be a highly productive. During a packed schedule, 50 baited remote underwater video surveys were completed; more than 240 linear km of bio-acoustic and surface visual transect data was collected; 48 sharks and tuna were tagged with satellite-linked and acoustic tracking devices; and over 100 zooplankton trawls and water column (CTD) profiles were conducted.
The project unequivocally established the importance of Ascension’s southern seamounts (Grattan and Young) as biodiversity hotspots for pelagic sharks and fish and was able to propose evidence-based MPA boundaries to ensure their protection.
The principle scientific expedition to Ascension Island’s outlying seamounts was timed to coincide with a National Geographic Pristine Seas expedition aboard the British Antarctic Survey (BAS) research vessel the RRS James Clark Ross (JCR) which enabled the delivery of a significantly scaled-up scientific programme. As a result of these additions, more than double the anticipated number of sites were surveyed.
The project also produced the first high resolution bathymetric maps of the seamounts being surveyed, which revealed their complex and varied geomorphology in unprecedented detail. The unnamed seamount, which was the least known prior to the expedition, proved to be particularly interesting, consisting of a chain of shallow peaks, some rising to within 70 m of the surface, with significant aggregations of sharks and other large predatory fishes.
An application has now been submitted to name this unnamed feature after a long-term island resident and conservation advocate who was among the first people to dive in Ascension’s waters.
The project will result in the designation of statutory marine protected areas, informed by detailed reports and datasets that have been archived on Ascension Island and will be made permanently available through a regional information management system.
There is growing international awareness in the need to rapidly expand our understanding of seamount ecosystems and increase their representation in marine protected area networks. The results of this project make a valuable contribution to that global agenda and employ a novel combination of fishery-independent research methods that could be applied more generally for studying seamount megafauna assemblages in other large MPAs.
Work was carried out from two offshore vessels: James Clark Ross (multibeam and oceanography) and M/V Extractor (tagging and survey elements)
Communication and project visibility:
Preliminary findings from the project were presented at the 4th International Marine Protected Areas Congress in Chile in September 2017, featuring in two oral presentations:
**Weber S (2017) “The Ascension Island Ocean Sanctuary: Planning for the Atlantic’s largest marine protected area”. 4th International Marine Protected Areas Congress, 4th – 8th September 2017, La Serena, Chile.
**Richardson A (2017) “An ecological assessment of Ascension Island’s shallow-water seamounts as candidate MPAs”. 4th International Marine Protected Areas Congress, 4th – 8th September 2017, La Serena, Chile.
The project team also contributed to the BEST 2.0 side event held at IMPAC4.
Project staff attended the 2017 annual meeting of Big Ocean Network, where progress with plans for a large-scale marine reserve at Ascension Island, including preliminary findings from the BEST 2.0 project, were presented to managers from all of the world’s largest MPAs.
A public talk was organised on Ascension Island immediately following the 2017 seamount expedition and attracted a record audience for a conservation-themed lecture. The talk featured a short film prepared by National Geographic Pristine Seas which included interviews with the project team.
Project activities have been reported in two articles submitted to the annual newsletters of the Darwin Initiative (a co-funder of the ASIOS project) and the South Atlantic Environment Research Institute (regional BEST 2.0 hub).
A proposal has been submitted to the International Hydrographic Office and Intergovernental Oceanographic Commission to name the third, currently unnamed shallow-water seamount in Ascension Island’s EEZ after a well-respected local diver and long-term Island resident (Jimmy Young) who has been a passionate advocate for greater protection and understanding of Ascension’s marine environment.