Why ocean animals are in deep trouble

_Elsa_

‘Human activity killed off 500 species of land animals in just the past 500 years. In the ocean, where scientists count only 15 or so such losses, the numbers aren’t yet that dire.

Many scientists have identified the birth of the Industrial Revolution as one of the tipping points for increased extinctions on land. Hunting drove desirable species 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?” says study coauthor Steve Palumbi, 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.”

Types of partial extinction

There are multiple instances of local extinction, in which a species disappears in one place but exists elsewhere. And there’s commercial extinction, when a species is still present, but no longer abundant enough to be profitably fished. Grey whales fell into this category in 1899 when there were only a thousand or so left—too few to keep the whaling ships coming back to Baja. 

A third type of extinction, ecological extinction, might be the most damaging. In this case, the species is still present, but has been overexploited to the point that it cannot play its traditional ecological role. Sea otters fell into this category when they were hunted so severely that they could no longer keep West Coast kelp forests healthy and growing.

And all these problems are on course to grow as industrial use of the oceans grows. Open ocean aquaculture, wave power, wind power, robot fishing—all these industrial uses of the sea are ramping up around the world. These ventures place the oceans, in the next 100 years, in the same place as the land in the past 100 years—centers of habitat destruction, range loss, and species loss..’ (Source)

Our poor Tiffi is getting upset that some of the ocean species might become extinct.

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