Increasing South Pacific aquaculture with complete ecosystems

The University of the South Pacific (USP) proposes to initiate the South Pacific Islands Restorative Aquaculture Program (SPIRAP) in support of its 12 member and other associate countries. All South Pacific nations are vulnerable to the impacts of climate change which are exacerbating the issues of food security, poverty, loss of land, wild fisheries decline, and pollution increases in sheltered bays and lagoons. The SPIRAP will be based at the USP Suva campus and will provide students from across the Pacific models of sheltered water restorative aquaculture facilities. Restorative aquaculture involves establishing a complete ecosystem with ample substrate where the density of each species matches the “wastes” from other species which are nutrients for that species. For example, the rivers deliver sediment, microalgae, and plant nutrients from human activities. Bivalves remove sediment and microalgae so that seaweed can grow on the plant nutrients.

Laucala Bay, adjacent to the USP Suva campus, is an example of a polluted area from a large coastal urban population and industrial activity plus past over-fishing, which has resulted in damaged fisheries. Candidate species for fisheries restoration include: giant clams, oysters, mussels, other native edible bivalves, crabs, shrimps, sea cucumbers, sea urchins, sponges, herbivore finfish, filter-feeding finfish, predatory finfish, and more. Supporting species needed to improve ecosystem yield include: seaweeds, seagrass, mangroves, epiphytes and many tiny sea creatures. Our calculations suggest that a 1 km² area of increased substrate and planted species (in the 30 km² bay) will yield more than 10,000 tons/year of healthy seafood after a few years of establishing the ecosystem and managing the nutrient flows and species populations.