Applying an Ecosystem-based Approach to Fisheries Management: Focus on Seamounts in the Southern Indian Ocean

The pilot project aims to develop a conservation and management framework for biologically- globally significant and commercially-important areas beyond national jurisdiction in the Western Indian Ocean, focusing on seamounts and shallow banks.Due to their typically high biological productivity and diversity, seamounts around the world have long been the target of commercial fisheries. Fishing activities can impact both target and by-catch species of corals, fish and crustaceans and impact the benthic communities of seamounts. The Coco-de-Mer Seamount chain, located just north of the equator at longitude 56.00E (north of the Seychelles EEZ) is a good example of a high seas seamount ecosystem that is fairly accessible, supports commercial fish stocks and should not have been extensively damaged by deep sea trawling. At least two fishing vessels are known to fish the seamounts, each year harvesting roughly 7,000 tons of tuna and tuna-like species using purse seine nets. While this does not represent a major fishing operation in global terms, it does present an excellent opportunity to assess the impacts of this type and scale of fishing on seamount habitats, develop a better understanding of the linkages between seamounts and pelagic species and assess the biological diversity of a potentially untouched seamount habitat. A management plan, based on this data and consistent with the UN Convention on the Law of the Sea (UNCLOS), should be developed to ensure that the seamount ecosystem is sustainably harvested and its biodiversity protected.Another important feature found in the high seas of the Western Indian Ocean are shallow banks and shoals, notably those that make up the Mascarene Ridge. These shoals and banks are known to provide important breeding grounds for oceanic megafauna as well as commercially important pelagic species due to the upwelling of nutrients that occurs at the outer edges of the banks. It is thought that commercial fishing activities (typically mothership-dory operations) on the banks are fully exploited, but more information is needed, not only on the fishing activities but also on the biological diversity found at the interface between the shallow banks and adjacent deep seas is needed to support a management framework. Dialogue would be conducted with institutions operating in the area. This buids on a similar effort in the Pacific approved by the GEF council.While very little information is known about these important components of high seas ecosystems in the Western Indian Ocean, fishing pressures exist that could do irreparable damage to as-yet undiscovered biodiversity and decrease commercially valuable fish stocks. In a review of coral occurrences on seamounts, out of 3200 records, globally, only 5 are from the Indian Ocean (AD Rogers in prep). The precautionary principle requires us to increase our knowledge of the ecosystem services seamounts and shallow banks provide and develop appropriate management mechanisms to ensure that they maintain their ecological integrity over time.