Stanford Report
16 January 2015
In the past 500 years, human activity has led to 500 species of land animals going extinct, a rate that has caused scientists to warn of a sixth mass extinction.
Although the situation in the oceans might seem less dire, with only 15 extinctions of marine animals in this period, a group of scientists now warn that rapid industrialization of the seas could spell a similar fate for marine life.
In a new paper published in the journal Science, a scientist from Stanford and colleagues from several universities write that the same patterns of human activity that led to the collapse of hundreds of species on land are now occurring in the sea, just a century or so later.
Many scientists have identified the birth of the Industrial Revolution as one of the tipping points for increased extinctions on land. Desirable species were hunted to extinction. Demand for lumber and expanding farmlands and factories meant leveling forest habitats. Pollution and other factors killed other animals.
Two hundred years later, the industrialization of fishing has ocean life facing similar pressures. Instead of sailing ships, satellite-guided supertrawlers now tow lines that stretch hundreds of miles. Overexploitation of fisheries has culled the population of large fish, such as tuna, by 90 percent. Shrimp farms are taking over mangroves, and 300-ton mining machines are pursuing seafloor mining claims with gold-rush–like fervor.
“There’s a conundrum: How can the ocean be overexploited and yet the species are still there?” said study co-author Steve Palumbi, the Harold A. Miller Professor and Director of Stanford’s Hopkins Marine Station. “The answer is that, especially in the ocean, there’s not just absolute extinction, but several types of partial extinctions, and that’s what we’re seeing now.”