Green Options

By Lester R. Brown

After World War II, accelerating population growth and steadily rising incomes drove the demand for seafood upward at a record pace. At the same time, advances in fishing technologies, including huge refrigerated processing ships that enabled trawlers to exploit distant oceans, enabled fishers to respond to the growing world demand. In response, the oceanic fish catch climbed from 19 million tons in 1950 to its historic high of 93 million tons in 1997. This fivefold growth—more than double that of population—raised the wild seafood supply per person worldwide from 7 kilograms (15.4 pounds) in 1950 to a peak of 17 kilograms in 1988. Since then, it has fallen to 14 kilograms.

As population grows and as modern food marketing systems give more people access to these products, seafood consumption is growing. Indeed, the human appetite for seafood is outgrowing the sustainable yield of oceanic fisheries. Today 75 percent of fisheries are being fished at or beyond their sustainable capacity. As a result, many are in decline and some have collapsed.

While oceanic fisheries face numerous threats, it is overfishing that directly threatens their survival. Oceanic harvests expanded as new technologies evolved, ranging from sonar for tracking schools of fish to vast driftnets that are collectively long enough to circle the earth many times over. Indeed, a 2003 landmark study published in Nature concluded that 90 percent of the large fish in the oceans had disappeared over the last 50 years, as a result of this expansion.

With apologies to both Stephen King and Verizon Wireless, the “real” Dead Zones we need to talk about are hypoxic (low-oxygen) areas in the world’s water systems that can no longer support aquatic life. As Joshua Hill, over at Plantsave has eloquently said,

Dead zones are created, in the beginning, by nitrogen (among other things). Nitrogen is the byproduct (in this instance) of natural gas transformed in to ammonia fertilizer, which is then spread across the agricultural landscape of many western and emerging nations.

From there the runoff makes its way to streams, then rivers and finally the oceans. It is at this stage upon reaching the ocean that the real trouble begins. The increase of nitrogen in the waters fuels the increase of algae which subsequently absorbs exorbitant amounts of oxygen, making life unbearable for most creatures…

It’s not only the Gulf of Mexico that’s suffering from “dead zones” caused by  excess nutrients, such as nitrogen and phosphorus used as fertilizers.

Marine dead zones are spreading in the Baltic sea, and that could cause the entire ecosystem to collapse for lack of oxygen.  Dire warnings from Lasse Gustavsson, Swedish head of the World Wildlife Funds branch in Sweden.