Fisheries and aquaculture face multiple risks from climate change

The study, 'Climate change implications for fisheries and aquaculture', is one of the most comprehensive surveys to date of existing scientific knowledge on the impacts of climate change on fisheries and aquaculture. Covering some 500 scientific papers, the picture the FAO review paints is one of an already-vulnerable sector facing widespread and often profound changes.

The report includes contributions from experts from around the world, including Dr Tim Daw and Prof Katrina Brown of the School of International Development and Prof Neil Adger of the School of Environmental Sciences at UEA. Other contributors come from the WorldFish Center, Globec, Network of Aquaculture Centres in Asia-Pacific, and Fisheries and Oceans Canada.

Dr Daw and Profs Adger and Brown co-authored the chapter 'Climate change and capture fisheries: potential impacts, adaptation and mitigation', which looks at the social vulnerability of fisherfolk to climate change. "Marine and freshwater ecosystems will be profoundly affected by processes like ocean acidification, coral bleaching and altered river flows with obvious impacts on fisherfolk, but it is not just about what happens to the fish," said Dr Daw. "Fishing communities are vulnerable to sea level rise and their livelihoods are threatened by storms and extreme weather. Meanwhile, the social and economic context of fisheries will be disrupted by impacts on security, migration, transport and markets."

"Fisheries are already rapidly evolving due to overexploitation and globalisation. They will suffer from wide range of different impacts from climate change, which may be unpredictable and surprising. The poorest will be least able to adapt to these impacts. For example in Kenya poorer fishers were shown to be less likely to switch to other livelihoods if catches declined."

Prof Adger added: "Climate change is going to be a huge challenge to every sector of society and what we're learning about fisheries shows how difficult adaptation will be, particularly for the poorest parts of the world."

According to the report, marine capture fisheries already facing multiple challenges due to overfishing, habitat loss and weak management are poorly positioned to cope with new problems stemming from climate change. Small island developing states -- which depend on fisheries and aquaculture for at least 50 percent of their animal protein intake -- are in a particularly vulnerable position.

Some 520 million people depend on fisheries and aquaculture as a source of protein and income. For 400 million of the poorest of these, fish provides half or more of their animal protein and dietary minerals. Many fishing and coastal communities already subsist in precarious and vulnerable conditions because of poverty and rural underdevelopment, with their wellbeing often undermined by over-exploitation of fishery resources and degraded ecosystems.

Inland fisheries -- 90 per cent of which are found in Africa and Asia -- are also at risk, threatening the food supply and livelihoods of some of the world's poorest populations. Warming in Africa and central Asia is expected to be above the global mean, and predictions suggest that by 2100 significant negative impacts will be felt across 25 per cent of Africa's inland aquatic ecosystems.

Fish farming will also be affected. Nearly 65 per cent of aquaculture is inland and concentrated mostly in the tropical and subtropical regions of Asia, often in the delta areas of major rivers at the mid- to upper levels of tidal ranges. Sea level rise over the next decades will increase upstream salinity, affecting fish farms.

A crucial issue highlighted by the report relates to how well such communities will be able to adapt to change. For example, even if African coastal fisheries do not face huge impacts, the region's 'adaptive capacity' to respond to climate change is low, rendering communities there highly vulnerable even to minor changes in climate and temperature.