TEXT OF STORY

Bob Moon: A little suspense now: Dun-nah . . . dun-nah . . . dun-nah . . .

OK, I was forced to do that because this Sunday is the start of Shark Week -- Discovery Channel's annual advertising cash cow. Yesterday, the federal government tightened regulations meant to discourage killing of sharks in the Gulf and Atlantic just for their fins.

Sharks might have the world's worst PR -- there are loan sharks and card sharks -- but as Marketplace's Steve Henn reports, sharks are key to some of our own economic health.

Steve Henn OK, so we all know sharks are scary. But what scares a shark? How about this: A little sesame oil, a spring onion, a sprinkle of ginger . . . those are the basics of shark fin soup.

Elizabeth Griffin is a Marine Wildlife scientist at Oceana:

Elizabeth Griffin: Shark fin soup is the primary factor driving the decimation of shark populations all over the world.

Shark fins taste like tough, slimy noodles. But they're so popular in China that Griffin estimates the soup is responsible for half the global shark catch.

Griffin: When you start to remove shark species from the ocean it causes very devastating and very unpredictable consequences.

Big sharks keep second tier-predators in check. Without them, rays in North Carolina wiped out the state's scallop fishery worth more than a million dollars. Now, scientists say those ravenous rays are hunting for Virginia clams.

In Washington, I'm Steve Henn for Marketplace.