Scientific findings indicate that aquatic climate change impacts are becoming more apparent and will continue to have a profound effect on the productivity of fisheries and the distribution of fish stocks around the world. However, there is a great deal of uncertainty associated with climate change in a fisheries context, particularly with respect to when it will occur, what kind of changes will take place and the extent of the impact it will have on aquatic ecosystems and fisheries. While global models exist and provide some indication of the magnitude of impacts, much work needs to be done at the local level in terms of understanding how fish stocks will react to changes in their environment, as well as how ecosystems will change. From a social and economic point of view, it is clear that the effects of climate change will result in the redistribution of costs and benefits for the fisheries sector and for coastal communities, but how much, when and to whom these benefits and costs will flow are less clear. In this regard, there is a need for fisheries policy makers to develop strategies and decision-making models to adapt to climate change under uncertainty, while also taking into account social and economic consequences.

Recent scientific findings, including the 2007 Intergovernmental Panel on Climate Change report (IPCC, 2007) indicate that the global effects of climate change are becoming more evident. Climate change is likely to influence fisheries and aquaculture production in various ways. For capture fisheries, climate change affects fish productivity and distribution through changes in recruitment, growth rates and mortality rates, as well as in the migratory patterns of some stocks. From an economic point of view, these changes will result in losers and winners, between regions or countries as well as within national jurisdictions. With respect to aquaculture production, climate change may necessitate changes in the species composition farmed in some areas depending on tolerability of the species to temperature and other changes. Other possible impacts of climate change on aquaculture include changes in feed composition and supply as well as changes in the type, scope and extent disease outbreaks in fish farms. For both sectors, relocation of aquaculture production sites, wild harvest landing sites (e.g. ports), and fish processing facilities may be required due to extreme weather events, changing stock distribution and location relative to markets.

Most (84%) of the warming due anthropogenic climate change has been transferred to the oceans. This chapter outlines the causes and consequences of climate change and summarise future projections for ocean temperature rise, coral bleaching events and ocean acidification, and the associated uncertainties. This review largely focuses on marine ecosystems, as three quarters of capture fisheries landings come from the seas. However, it also presents key issues and examples from freshwater fisheries, as these fisheries provide important livelihoods and fish protein for some of the world’s poorest people. While the physical and biological effects of climate change are increasingly well understood, particularly for well-studied temperate shelf ecosystems, relatively little is known of the likely impacts for ecosystems elsewhere and their associated fisheries. Overall, on balance, climate change appears to have impacts on fish ecology and fisheries, but the strength and direction (positive or negative) of the effects vary from place to place. The social and economic effects are less clear; however it is likely that the economies of countries with the lowest levels of adaptive capacity will be most vulnerable to the effects of climate change on capture fisheries and less able to anticipate and capitalise on any advantages of climate impacts. Despite the uncertainty surrounding the direction and degree of the impact of climate change on marine and freshwater ecosystems, and the associated fisheries and fishing communities, the options for policy makers are relatively clear. Policy makers can respond by pursuing mitigation strategies (reducing CO² emissions), building socio-ecological resilience and capacity to enable fishing communities to cope with and adapt to the opportunities, challenges and potential dangers presented by climate change, and by integrating the management of natural resource sectors in a portfolio approach.

This chapter addresses climate change effects in capture fisheries and options for policy response. Climate change creates both physical and biological pathways of impacts on marine fish that affect fishery economic performance, which in turn influences management effectiveness and shapes the landscape of policy response. This chapter discusses the linkages between these issues.

Climate changes, such as global warming, decadal climatic regime shifts and interannual variability of the El Niño-Southern Oscillation (ENSO) phenomenon, can affect ocean conditions and thus affect the functioning of marine ecosystems as well as the distribution and abundance of fisheries resources. For example, there has been a trend of increasing sea surface temperatures in Korean waters, which has accelerated in the last decades. This recent warming trend is associated with a decline in cold-water species (e.g. walleye pollock) and an increase in warm-water species (e.g. common squid and bluefin tuna). It is also associated with changes in the distribution of fish stocks such as chub mackerel in Korean waters.

This report is presented in response to the request by the Fisheries Committee of the OECD as a submission to the international workshop on “The Economics of Adapting Fisheries to Climate Change” to be hosted the OECD Committee for Fisheries and the Fisheries Policies Division and held on June 10-11, 2010 in Busan, Korea. The workshop addresses what fisheries policy makers should do in order to develop adaptive and flexible fisheries management regimes to the changing climate and help the transition of fishing industries and communities.

Climate change implies a certain degree of uncertainty in terms of temporal and spatial variations of fish populations, habitat viability and stability, and ecosystem interactions and feedbacks (Kirby et al., 2009). Since the ultimate effects of climate change are still unknown, one can only stress that fisheries policy makers and managers (should) be precautionary when assisting fishers, their communities and stakeholders to adapt to the bio-physical, social and economic consequences of climate change.

The fishing industry is a primary example for an industry subject to nature’s variability, including climate change. Climate change affects fisheries along two main axes, changes in productivity in a given location and changes in fish migrations or the location of their habitats. Based on IPPC reports and other sources the paper summarizes expected changes in the marine environment. It then looks into potential fisheries productivity implications by drawing on examples from changes that occurred in the past. The paper also outlines the impacts of changing fish migration patterns of shared stocks, again illustrated by examples from the past. Those changes can influence the behaviour of the partners exploiting a shared stock, with critical consequences for the status of the stock and/or the relationships between the partners of an agreement. The paper further illustrates that if those changes affect stocks located entirely or partially in the high seas, shared management through RFMOs becomes even more challenging.

In this chapter, impacts of climate change on high seas, straddling and highly migratory stock fisheries are discussed in the context of capture fisheries trends and socio-economic implications. Factors considered include impact pathways, impact effects, future impacts and relationships to other trends. The exposure and sensitivity of fisheries to climate change are considered in terms of “vulnerability” and “resilience”. Climate change “adaptation” and “mitigation” are highlighted, noting a need to explicitly account for uncertainty in available climate impact information and potential fisheries responses. Gaps in current knowledge of climate change impacts are identified for high seas, straddling and highly migratory fish stocks. A need for relevant institutions to provide anticipatory adaptation measures to minimise impact(s) is recognised. Consequently, increased environmental and fisheries uncertainty have serious implications for the management of climate-impacted fisheries.

With increased storminess, rising sea levels and changes in ocean circulation, the British seas are becoming warmer and more acidic, entailing changes in the location and distribution of species. Alongside endemic problems such as overfishing, overcapacity and discarding the biological sustainability of stocks, climate change poses an additional pressure.

Climate change has become an issue of increasing importance in Korea, as an average sea surface temperature has risen significantly over the last decades and affects fisheries production and the distribution of fish stocks. This is of particular concern to fishers and coastal communities as they experience the effects of climate change on a regular basis.

This chapter describes the impact of climate change on Chinese Taipei fisheries and introduces how Chinese Taipei addresses the challenges. Accelerating sea surface warming in the waters surround Chinese Taipei since the 1980s has not only diminished winter migratory fish stocks year on year, but also caused such changes as displacement of fishing grounds, species regime shifts and increased the vulnerability of the marine ecosystem. The marine ecosystem and fisheries have to face the problem of the expansion of fish stocks from the south and withdrawal of fish stocks from the north. In addition, the numbers of large fish at high trophic levels have decreased under pressures from several decades of fishing activity while small pelagic fish have shown a relative increase. As the numbers of small pelagic fish show much greater inter-annual fluctuations than those species of larger size or longer lifespan, this is likely to weaken the structure of marine food (fish) pyramid even more. Meanwhile, frequent extreme-weather events and climatic variability during the warming process will damage the Chinese Taipei fishery more. Under such circumstances, traditional fishery management measures will not be able to adapt to the problems caused by climate change. External precautionary and adaptation measures need to be introduced to reduce its impact.