Roy Scheider thinks we need a bigger boat.

In the 1975 blockbuster movie “Jaws,” Mayor Larry Vaughn tries to prevent Police Chief Martin Brody from disclosing shark attacks off fictional Amity Island.
“It’s all psychological,” Mayor Vaughn says. “You yell ‘Barracuda!’ and everybody says, ‘Huh? What?’ You yell ‘Shark!’ and we’ve got a panic on our hands on the Fourth of July.”
The Missouri Department of Natural Resources apparently performed similar calculus just as the summer tourist season was beginning at Lake of the Ozarks. But instead of a man-eating monster, its fear was inspired by a microscopic bacterium called escherichia coli — e. coli for short.
Testing revealed levels of e. coli at the lake that were, in some cases, 19 times the maximum allowed for safe swimming.
DNR officials, including Deputy Director Joe Bindbeutel, a long-time former aide to Gov. Jay Nixon, worried that reporting those test results would hurt tourism. So the results were withheld for a month, until further tests showed e. coli levels had subsided.
That’s dangerous, unprofessional and unacceptable.

E. coli kills way more people than sharks.
There were just 56 shark attacks, resulting in four deaths, around the world in 2008. In the United States alone, e. coli infects an estimated 70,000 people each year. Between 3,500 and 7,000 of them — many children, the elderly and those with compromised immune systems — develop a life-threatening complication that causes their kidneys to shut down.
Most of those people are sickened by eating under-cooked or improperly washed food. But the U.S. Centers for Disease Control and Prevention has reported recent outbreaks caused by “swallowing lake water while swimming and touching the environment in petting zoos.”
State health officials say they know of no one who was infected by swimming at the lake. But that’s not as comforting as it sounds. Diagnosing e. coli infection requires laboratory tests of stool samples. Even when infected people visit a doctor, that’s often not done.
Even if it were, tracing the source of contamination to the lake would be difficult or impossible. That’s because visitors to  the lake would have been exposed to numerous strains of the bacterium.
What’s more, symptoms could take as long as 10 days to appear. By that time, visitors could be far away and their vacation at the lake would seem unrelated.
“Things will be done differently in the future,” DNR Director Mark Templeton promised on Friday. He said Mr. Nixon has ordered test results to be released sooner.

Boats jockey for position at the entrace to Party Cove at Lake of the Ozarks.

But why is DNR involved at all? At some other Missouri lakes and in many other states, water quality testing at beaches and swimming areas is performed by local health departments. Public health professionals are better equipped to evaluate and respond to threats posed by e. coli and other bacterial contamination. Their job is to protect the public health, not promote tourism.
Even if responsibility for testing is transferred, DNR officials — and Mr. Nixon — still owe the public a fuller accounting of what went wrong.
Why, when the results came in, did the DNR not immediately retest to search for possible contamination sources such as broken or leaky septic systems, over which it has jurisdiction.
Why weren’t test results released when environmental groups requested them under the state Sunshine Law?
And how could anyone have thought that protecting tourism was more important than protecting the public? Where’s Chief Brody when we need him?