First the Big Sea Beasts, Then the Rest
Loss of large sea creatures triggers ecosystems' decline

View a photo essay of three affected ecosystems

Hear the segment from All Things Considered

July 26, 2001 -- Gray whales in the Chesapeake Bay. Five-foot-long codfish off the Massachusetts coast. Tens of millions of 500-pound turtles in the Caribbean sea. Though such a bounty of large sea creatures sounds like the tall tales of fishermen, it used to be fact, says a new paper in the journal Science.

Codfish caught in a net Photo: OAR/NURP

The researchers argue that when humans started killing and eating these big sea animals, aquatic ecosystems started a long downward spiral - one that continues, in some places, to this day. On All Things Considered, NPR's John Nielsen examines the new findings.

What scientists now know about this abundant sea life, they owe in part to a pirate named William Dompier. Though Dompier was a rogue and a cutthroat, he "had a great scientific eye," says marine scientist Jeremy Jackson of the Scripps Institute of Oceanography in California. In the early 1700s, Dompier wrote in detail about Caribbean flora and fauna. After studying Dompier's notes on giant green turtles, and old British records of turtle hunting, Jackson concluded that as many as 40 million of the turtles may have lived in the Caribbean in Dompier's time.

Green Turtle Photo: Peter Bennett/Ursula Keuper-Bennett

What was true for turtles was also true for whales, manatees, monk seals, swordfish, sharks, codfish and more, according to Jackson and 17 colleagues who co-authored the Science paper. Their research evaluated dozens of historical references to large and abundant marine creatures - and also to equally important smaller creatures. Writing in 1608, explorer John Smith described oyster reefs so massive that they posed a danger when navigating the James River.

Like most of the species studies in the report, oysters were the anchor of a flourishing ecosystem. What happened, say the authors, is that all these ecosystems started falling apart when the keystone species were fished to the brink of extinction. Still, paper co-author Pete Peterson says there is a positive side to the findings. While many species on land already have been wiped out, "in the marine environment, the numbers of extinctions are few," says Peterson a marine scientist at the University of Carolina. This means "we have an unusual opportunity to restore some of the past."

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