Marine Atlas: Maximizing Benefits for Solomon Islands

FISH FROM THE FARM: AQUACULTURE

Aquaculture has become a developing sector in Solomon Islands over the years. While this sector has great potential to provide people with food and livelihoods, its devel- opment should be balanced against other coastal and ocean uses.

The farming of seafood, known as aqua- culture, can be practised in either fresh water or saltwater, the latter of which is also known as mariculture (see map). The further development of aquaculture in Solomon Islands could contribute to food security, sustainable livelihoods and economic growth for current and future generations. At present, the gap between the sustainable supply of seafood from wild fisheries and food security demands is growing. Aquaculture in Solomon Islands is still in its infancy, but it is being actively pro- moted as a means of supplying food and livelihoods, especially in rural communi- ties. It is also seen as a means to build the country’s economic growth through the development of an export industry. At present, marine aquaculture development in Solomon Islands is focused on two main areas: seaweed aquaculture and sea cucumbers for stock enhancement. There is also low-scale farming of the non-native Mozambique tilapia ( Oreochromis mos- sambicus ) in freshwater ponds, particularly in Malaita and Guadalcanal. The main target species of seaweed aqua- culture is elkhorn sea moss ( Kappaphycus alvarezii ). This tropical red alga can grow up to 2 metres in length and can double its biomass in 15 days under ideal growing conditions. Carrageenans are extracted from the harvested algae, which are used as gelling, thickening and stabilizing agents in foods. They are also used in the cosmet- ic industry and even mining. The Ministry of Fisheries and Marine Resources first assessed the aquaculture feasibility of this species in 1998, continuing such work with subsequent projects until 2012. There are currently seven active seaweed farms in

Due to this species’ slow growth rates, the Ministry of Fisheries and Marine Resourc- es is looking at options to farm the faster growing Nile tilapia ( Oreochromis niloti- cus ), also known as Genetically Improved Farmed Tilapia (GIFT) (Ministry of Fisheries and Aquatic Resources, 2015). Although aquaculture offers Solomon Islands several benefits, it also has some negative impacts on the country’s marine ecosystem. These include pressure on wild fish used for fish feed, escape of intro- duced aquaculture species, interbreeding of farmed fish with wild fish, pollution and habitat loss. For example, mangroves are cut to develop shrimp farms, resulting in loss of this key coastal habitat (see also

chapter “Home, sweet home”). There is therefore a need for clear priorities when expanding aquaculture to minimize any adverse environmental impacts.

Solomon Islands (see map), making the country the largest seaweed producing na- tion in the Pacific (Ministry of Fisheries and Marine Resources, 2015). The largest sea- weed production comes from Wagina, with more than 50 tons produced per month. In 2014, Solomon Islands’ annual seaweed production was over 1,500 tons, which was worth over SI$5 million (Ministry of Fisher- ies and Marine Resources, 2015). Sea cucumbers and tilapia—the other two main target species for aquaculture—are produced at a smaller scale than seaweed aquaculture. The Overseas Fishing Cooper- ation Foundation supported the establish- ment of a marine hatchery to research the biology of a type of sea cucumber locally

known as peanutfish ( Stichopus horrens ). Juvenile peanutfish have been used in a trial restocking at Marau in north-eastern Guadalcanal. As is the case in other Pacific Islands, there is growing interest in com- mercial sea cucumber aquaculture in Solo- mon Islands. However, there are challenges with developing a profitable model for this industry (Pakoa et al., 2014). Tilapia aquaculture is produced as a food source, directly consumed by the farmers or sold at local markets. The main target species is the non-native Mozambique tilapia ( Oreochromis mossambicus ). This aquaculture is produced in land-based freshwater ponds, mainly in rural areas on the islands of Malaita and Guadalcanal.

MAXIMIZING BENEFITS FOR SOLOMON ISLANDS

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