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Humans, and all life on Earth, descends from ancient sea organisms, so it’s no surprise that our bodies crave nutrients from sea plants and animals to sustain ourselves. One example is fish oil, omega-3, which helps make us smarter. People have eaten fish since our species got started, and “mariculture,” cultivation of marine organisms in seawater, goes back thousands of years. As with other natural systems, world population increase from three billion people in 1950 to over seven billion now, coupled with higher standards of consumption, have stressed and changed the world ocean. Cullum Roberts’s book, “The Ocean of Life,” is an excellent, detailed, 2012 analysis of the 70 percent of Earth covered by salt water, our reliance on its productivity for survival, and challenges we face to protect it.
In the past few decades, mechanized ocean fishing has depleted wild populations, particularly of larger fish, and the world depends more on fish farming. China leads the world in mariculture, with almost half of its coastline dedicated to fish farms. Environmental costs of that Chinese food-production strategy include loss of mangroves and other portions of China’s natural seacoast which formerly served as ocean nurseries, as flood control, and as pollutant removers. America has been doing a better job, both in government and in private watchdog organizations. The Marine Stewardship Council has about 11,000 MSC-labeled products around the world, certified as fish that are safe for the consumer to eat, for the environment, and for the species’s survival. The Blue Ocean Institute has a “From Sea to Table Sustainable Seafood Program”, which has guidance as titled.
Many of us were brought up assuming that the world ocean was practically infinite, and that nothing man could do would make much of a difference. The Texas-size island of plastics floating in the Pacific, the precipitous declines in large marine life, increasing acidity of seawater, and the ocean’s heating up as we continue to burn four cubic miles of hydrocarbons a year has changed that. Jellyfish, on the other hand, are doing very well – they’re simple, adaptable animals which multiply quickly in oceans with fewer predators and happily replace the game fish trawlers sweep away.
Image by Ian Capper [CC-BY-SA-2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons