Jellyfish for dinner, anyone?

National Geographic

‘The Ocean of Life’—And the Sorrow Beneath the Sea

Imagine an underwater world without whales, sharks, and dolphins, where jellyfish and algae rule. It's already happening, says marine biologist Callum Roberts in his new books, 'The Ocean of Life.'

by Callum Roberts  | May 14, 2012

Like children the world over, my daughters love turtles. At once incongruous and graceful, they connect us to the world of 15 million years ago, when very similar turtles swam alongside megatooth sharks, or 75 million years ago, when they rubbed shoulders with dinosaurs. Only eight species of marine turtle remain from a lineage that stretches back little changed deep into the age of dinosaurs. The largest living reptile is the leatherback turtle, a barnacle-encrusted eminence that can reach 10 feet long and weigh two tons. Today we confront the stark possibility that people will drive the leatherback turtle to extinction within the next human generation. Already there is just one leatherback left in the Pacific for every 20 in 1962, the year I was born.

Human dominion over nature has finally reached the sea.

With an ever-accelerating tide of human impact, the oceans have changed more in the last 30 years than in all of human history before. In most places, the seas have lost upwards of 75 percent of their megafauna—large animals such as whales, dolphins, sharks, rays, and turtles—as fishing and hunting spread in waves across the face of the planet. For some species, like whitetip sharks, American sawfish, or the once “common” skate, numbers are down as much as 99 percent. By the end of the 20th century, almost nowhere shallower than 3,000 feet remained untouched by commercial fishing. Some places are now fished down to 10,000 feet.

Why, in the face of widespread evidence of human impact, do so many people persist in thinking that the oceans remain wild and beyond our influence? The answer lies in part in the creeping rate of change. Younger generations are often dismissive of the tales of old-timers, rejecting their stories in favor of things they’ve experienced themselves. The result is a phenomenon known as “shifting baseline syndrome,” as we take for granted things that would have seemed inconceivable two generations ago.

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