Protecting Marine Ecosystems in the South Atlantic

The food security and economies of Tristan da Cunha and St Helena, British overseas territories in the South Atlantic, are heavily reliant on marine harvestable resources and, to a lesser degree, tourism. Understanding how vulnerable these resources are to current and future harvesting, the impacts of climate change and species invasion will be key to maintaining the future economic and cultural security of these nations.

The rock lobster fishery at Tristan da Cunha and the tuna fishery at St Helena are important for the islands economies and cultural identities. The Tristan lobster fishery is very well managed and has Marine Stewardship Council certification. However, there is a realisation that developing other sustainable fisheries would improve long-term economic security. Similarly, St Helena need more oceanic research to help them better manage their tuna fisheries.

This three-year project aims to leave a legacy of robust information about the marine ecosystem as well as oceanographic and food web modelling that will provide the scientific information necessary to develop policies to manage marine ecosystem resources, especially those relating to food security and eco-tourism. These will provide tools for the Islanders to manage their marine resources into the future.

As part of the project there are two cruises planned, one on board the RRS James Clark Ross in 2018 and one on board the RRS Discovery in 2019. During the cruises the team will deploy a range of sampling equipment to examine the biodiversity on the sea floor and in the water column. In addition, the ship’s multibeam echosounder will be used to build a detailed picture of the seafloor, which will help to create habitat maps.

Once these habitats have been identified, an underwater camera and small trawl will be used to describe the species present within each habitat. Bongo nets and a rectangular midwater trawl (RMT) will be deployed to sample animals in the mid-depths of the water column.

Identification and further analysis of the specimens, assessing stable isotopes and the genetic connectivity, will help to construct a food-web for the exploited marine populations. Using this information new modelling techniques will be used to identify critical links in the food chain and their potential vulnerability. These links can be used as an early warning sign for the marine ecosystem, highlighting the need for some remedial action in the region.

In parallel to the cruises this project builds on the ongoing sea bird research on the Islands, to help conserve the breeding and feeding grounds of many endemic species. New logger technology will be deployed to map the habitat usage of these species and help to predict vulnerable times and locations that can be the target for conservation measures.

Scientific cruises and land-based fieldwork will be complemented by ocean model simulations, allowing the team to understand the variability and eventually to identify any longer term trends, including climate change signals.

This project is supported by the UK Government Official Development Assistance (UK-ODA). This is one of two British Antarctic Survey projects that are supported by UK-ODA. Find out more about how we are applying our polar expertise to support development here. The project was designed to directly benefit the people of St Helena and Tristan da Cunha, with a strong focus towards economic improvement and protection of biodiversity.

This is a collaboration with multiple partners including the Tristan da Cunha and Saint Helena Governments, the Blue Belt Programme, Cefas, Marine Management Organisation (MMO), UK Hydrographic Office (UKHO), the RSPB, South Atlantic Environmental Research Institute (SAERI), Shallow Marine Survey Group, University of Plymouth and University College London.