Climate and Aquatic Food Production

Abstract

Ever since man started to gather marine and freshwater animals, the level of harvest has been influenced by the climate. In this report we consider the effects of climate on aquatic food production by aquaculture and by major fisheries in the high seas, in regions of upwelling, and in tropical riverine areas. Our main findings are: 1. The literature dealing with the relations between climate and aquatic food production is incidental to rather than elucidative of those relations. 2. Long-term climatic changes and short-term deviations from the climatic norm affect fishing activities and levels of aquatic productivity. 3. The most important overall effect of climate on aquatic food production is through variations in temperature, which influence the distribution, migration, growth, and availability of food for aquatic organisms. 4. Other important climate-induced changes in the environment affect ocean currents, wind patterns, and the onset of seasonal rains such as the monsoons. The changes may act through variations in food, or malfunction of physiological, or behavioral signals. 5. Enhancement of aquatic food production through climatic changes is difficult to measure but deleterious effects could reduce the annual global aquatic food production by more than 10 percent. 6. Aquaculture production is less affected by vagaries of climate than is fishing. 7. Improvements should be made in the methods of collecting fishery statistics to permit better resolution of the effects of climate and exploitation on fish stocks. As is true for other types of food production, more reliable and longer-range capabilities for predicting impending changes of climate are also desirable. 8. Based on very preliminary analyses, an increase in atmospheric carbon dioxide might result in slight increases in the natural occurrence of fishes and hence fish production.