Fishy Business

9/22/2014 biodiversity , fish , food , risks , sustainability 0 Comments

Aquaculture is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. At the moment aquaculture is the fastest growing food sector in the world. From 1990 to 2010 cultivation of fish and shellfish in terrestrial and marine systems grew at an annual rate of 7.8% worldwide, a much higher rate than any other food commodity. Although there are many potential benefits to farming aquatic organisms such as increases in food and fuel supply there are also many potential drawbacks. In this post I will go through some of the latest scientific findings regarding the pros and cons of aquaculture from a global food security perspective.

Fig.1 Map over societies dependence (%) on fish for nutrition (2008)

Fish is an important food commodity and more than 3 billion people obtain ⅕ of their animal protein from fish. Some societies are more dependent on fish as a source of nutrition than others (Fig. 1). In 2012 the global fish market was valued at 129 billion dollars. However, global wild fish catches peaked around 2002-2003 and is now at a plateau (Fig. 2a and b), thus, there is an sense of urgency in the scientific and public policy community to match the gap in food needed with sustainable options.The international community's interest in aquaculture has thus become ever more present. And business is booming, roughly half of the fish consumed worldwide now comes from aquaculture and its share is expected to increase in the future as wild fisheries exceed their sustainable limits (Troell et al. 2014). Freshwater fish comprise the majority of aquaculture production today. These fish are raised in ponds, lakes, canals, cages and benefit from a wide range of inputs, technology and management.

The most common environmental problems include pollution of marine ecosystems, destruction of coastal habitats, enhanced disease and parasite transmission between farmed and wild fish populations, introduction of invasive species, increased stress on freshwater resources, and overfishing of wild fish stocks to feed farm fish. The use of wild fish in feeds can also have food security implications for low-income households that depend on low-trophic level fish as a key source for nutrition.

Since there are both major benefits and risks to aquaculture one way to make a risk analysis is to use a portfolio approach. The basic idea is to invest in a suite of assets or activities that collectively has lower risk relative to that of any individual asset. This will yield trade-off options between risk and returns and the trick is to diversify the asset bundle. The degree of risk depends on correlations between assets’ returns. When applying this approach to the global food systems one could think of the targeted return as the aggregate output of food commodities needed to meet human demands. Risks, then, involve temporary and irreversible declines in productivity captured by the variation and trend in food production and prices. Furthermore, the degree of food price volatility is indicative of the global food system’s resilience (or robustness) against a wide range of stressors such as pests, extreme weather events, climate variability and other market shocks related to changes in the energy and financial sectors. A pattern of higher and more variable prices over time would then suggest deteriorating resilience of global food supplies whilst a pattern of stable prices would indicate a more robust and resilient food system.

Source: Troell et al. (2014)

Diversify, diversify, diversify

Conclusion