The Environmental Food Crisis

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

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