Our oceans are emptying at an alarming rate. Oceanographers monitoring the Marine Trophic Index—a measure of the stability of the ocean’s food chain—have discovered a disturbing trend over the past 50 years: Human consumption of marine animals has been drastically upsetting the balance of ocean life since the beginning of large-scale industrial fishing in the 1950s.
The culprit for this relatively sudden change in the ocean’s ecosystem is what University of British Columbia scientist Daniel Pauly describes as “fishing down the marine food webs.”1 After our overfishing of alpha-predators like tuna and salmon leads to their rapid dwindling, we begin eating lower down the ocean’s food chain. In the absence of their predators, species further down the chain experience a temporary population boom. Fishers respond to this newfound abundance by fishing them out of existence—and so on, down the food chain.
If this trend continues unabated, Pauly suggests, the future of seafood will be an unvarying supply of “jellyfish sandwiches.”2 An initially skeptical scientific community has confirmed Pauly’s fears, even going so far as to project an approximate date by which the world’s seafood supply will have run out based on the current rate of ocean fishing: as soon as 2050, according to the journal Science.3
Fish are not the only marine animals to suffer from aggressive commercial fishing practices. Techniques such as “bottom trawling” (in which nets are dragged thousands of miles across the ocean floor) indiscriminately destroy entire habitats of deep-sea species. Both bottom trawling and longlining (using large numbers of baited hooks on an extended line) devastate populations of dolphins, whales, sea turtles, seabirds, and other marine animals who are trapped in the nets or hooks as “bycatch.”
Unless we take immediate steps to dramatically reduce our consumption of sea life, the long-term damage to our oceans’ ecosystems may well be irreversible.
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Daniel Pauly et al., “Fishing Down Marine Food Webs,” Science, February 6, 1998.
Robert McClure, “Jellyfish for Lunch? It’s No Joke, Says Scientist,” Seattle Post-Intelligencer, May 4, 2004, http://seattlepi.nwsource.com/local/171765_fish04.html.
Boris Worm et al., “Impacts of Biodiversity Loss on Ocean Ecosystem Services,” Science, November 3, 2006.