The ocean may well be able to meet global demand for fish, despite increases in human population and climate change impacts on ocean productivity, if resources are managed sustainably across the world. This is one of the key findings of a paper published this week in Nature Climate Change.
An international team, led by scientists from PML and funded by the Natural Environment Research Council, has undertaken an innovative study of how climate change is expected to affect the physical and biological processes in coastal and shelf regions of 67 countries, and how these may affect the social and economic prosperity of their communities. Coastal and shelf regions were specifically targeted as they yield approximately 60% of total marine fish catches.
This first-of-its-kind model integration and advanced analysis looks at the impact of climate change on the potential productivity of the ocean combined with the countries’ dependency on fish and fishing. The team was able to investigate the economic sensitivity to projected change, such as impacts upon food security, employment and trade, highlighting countries with both a high dependency on fishing and a likely expectation of significant changes in fish catch into the future.
Results suggest a general increase in productivity in the higher latitudes (polar regions) and an overall decrease in production potential in the lower latitudes (tropical regions), although the changes are expected to be less than 10% of the current yields. A 3% increase in global productivity potential is also indicated.
Of greatest concern are the nations of South and Southeast Asia, Southwest Africa, Peru and some tropical, small-island, developing states. These countries’ relatively high reliance on fisheries, in terms of wealth, food and employment, and climate change is projected to have a negative impact on their potential fish catches. Nations that may benefit from changes are mostly along the West African coast and Iceland.
The team recognises that there will be “winners and losers”, and recommends strategies to help ensure the maximum potential of fish catches across the globe is achieved, including: coupled social and ecological assessments, essential tools to guide the development of climate change adaptation measures; successful implementation of strategies for sustainable harvesting; ongoing technological development in the aquaculture industry; full-use strategies with regards to catches and a reduction in discards, and an effective distribution network of wild fish products from countries with a surplus to those with a deficit.
Prof. Manuel Barange, PML's Director of Science, commented: “This is the first study to look at the physical and biological impacts of climate change on fish resources in coastal and shelf seas and on the social and economic impacts at national level. The models used have a high resolution of 6 x 6 miles and, thus, consider the impacts on processes such as river run-offs, tidal processes and coastal upwelling, often missed by lower resolution climate models.”
“We also focused on the whole ecosystem productivity and energy transfer as opposed to being species specific. Dominant species may change as the ecosystem adapts to new climate conditions but our study focuses on total biomass production, which is a more tractable process than species identity.”