Humans Have Brought World's Oceans to Brink of 'Major Extinction Event'

Marine wildlife at all levels of the food chain has been badly damaged by human activity, says a new report that urges immediate and “meaningful rehabilitation” if we are to avert mass extinction in the world’s oceans.

“We may be sitting on a precipice of a major extinction event,” Douglas J. McCauley, an ecologist at the University of California, Santa Barbara and an author of the study, told the New York Times

“Assessing the oceans from a holistic perspective is the only way to understand the scope at which we must act to reverse collapsing fisheries and continued habitat degradation.”
—Amanda Keledjian, Oceana

The report, published Thursday in the journal Science, finds that habitat loss, mismanagement of oceanic resources, climate change, and the overall “footprint of human ocean use” have resulted in a phenomenon known as “defaunation”—a decline in animal species diversity and abundance.

“Although defaunation has been less severe in the oceans than on land, our effects on marine animals are increasing in pace and impact,” reads the study abstract. “Humans have caused few complete extinctions in the sea, but we are responsible for many ecological, commercial, and local extinctions. Despite our late start, humans have already powerfully changed virtually all major marine ecosystems.”

“Humans have profoundly decreased the abundance of both large (e.g., whales) and small (e.g., anchovies) marine fauna,” it continues. “Such declines can generate waves of ecological change that travel both up and down ma­rine food webs and can alter ocean ecosystem functioning.”

Just as the Industrial Revolution during the 1800s decimated the huge tracts of forests, driving many terrestrial species to extinction, industrial use of the oceans threatens to destroy marine habitats and in turn damage the health of marine wildlife populations.

Report co-author Steve Palumbi of Stanford University listed several emerging threats to the oceans: “There are factory farms in the sea and cattle-ranch-style feed lots for tuna. Shrimp farms are eating up mangroves with an appetite akin to that of terrestrial farming, which consumed native prairies and forest. Stakes for seafloor mining claims are being pursued with gold-rush-like fervor, and 300-ton ocean mining machines and 750-foot fishing boats are now rolling off the assembly line to do this work.”