FOOD FROM FISHERIES AND AQUACULTURE
Aquaculture, freshwater and marine fisheries supply about 10% from bottom trawling, pollution and dead zones, invasive spe-
of world human calorie intake – but this is likely to decline or at cies infestations and vulnerability to climate change (UNEP,
best stabilize in the future, and might have already reached the 2008). Eutrophication from excessive inputs of phosphorous
maximum. At present, marine capture fisheries yield 110–130 and nitrogen through sewage and agricultural run-off is a
million tonnes of seafood annually. Of this, 70 million tonnes major threat to both freshwater and coastal marine fisheries
are directly consumed by humans, 30 million tonnes are dis- (Anderson et al., 2008; UNEP, 2008). Areas of the coasts that
carded and 30 million tonnes converted to fishmeal. are periodically starved of oxygen, so-called ‘dead zones’, often
coincide with both high agricultural run-off (Anderson et al.,
The world’s fisheries have steadily declined since the 1980s, its 2008) and the primary fishing grounds for commercial and ar-
magnitude masked by the expansion of fishing into deeper and tisanal fisheries. Eutrophication combined with unsustainable
more offshore waters (Figure 10) (UNEP, 2008). Over half of fishing leads to the loss or depletion of these food resources, as
the world’s catches are caught in less than 7% of the oceans, in occurs in the Gulf of Mexico, coastal China, the Pacific North-
areas characterized by an increasing amount of habitat damage west and many parts of the Atlantic, to mention a few.
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