Bluegills: Not Just for Fishermen Anymore

By Linda Orlando

Decades ago, miners who needed to know that the air down below was safe to breathe didn’t employ fancy meters or expensive gadgets. Instead, they used an air quality detector created by God—a canary. Now another one of God’s creatures is being used by some cities in the United States to be sure that the water is safe to drink.

Since the terrorist attacks of 9/11, the government has taken the threat of future attacks very seriously. One of the major concerns is the possibility of an attack on the U.S. water supply. For that reason, federal law requires that community water systems must assess their vulnerability to terrorism.

As a response to that requirement, San Francisco, Washington, D.C., New York, and other big cities around the country have begun using bluegills to detect whether or not there are toxins in the water system. Small groups of bluegills—also known as sunfish or bream—are kept in tanks that are regularly filled with water from the municipal water supply. Sensors in the tanks constantly monitor the fish to detect any changes in their breathing, heartbeats, or swimming patterns—changes that occur in the presence of toxins. The computerized systems used to monitor the bluegills is designed to detect even slight changes in the bluegills’ vital signs, and send an e-mail alert whenever something is wrong.

Large metropolitan areas regularly employ a wide range of safeguards against various biological and chemical agents. Water supplies are constantly monitored, tested, and treated. But the drawback of electronic protection systems is that they can trace only the toxins they are programmed to protect. Bluegills, on the other hand, are much more versatile. The hardy fish, about the size of a human hand, have systems that are highly attuned to chemical disturbances in their environment. When they are exposed to toxins, they repeatedly flex their gills to expel unwanted particles—a type of fish coughing.

"There’s no known manmade sensor that can do the same job as the bluegill," said Bill Lawler, co-founder of Intelligent Automation Corporation, a California company that designed and sells the bluegill monitoring system. "Nature’s given us pretty much the most powerful and reliable early warning center out there," Lawler said. But although bluegills have successfully detected at least 30 toxic chemicals, they aren’t as reliable at detecting germs and they can’t do anything about other sorts of attacks, such as bombings or physical damage to water mains or attacks on the systems that control water flow. But still, more than a dozen cities have ordered the bluegill monitoring system, which is called the Intelligent Aquatic Biomonitoring System. It was originally designed for the Army and sells for $45,000 and up.

New York City has been testing its water-monitoring system since 2002 and is planning to expand it. In at least one instance, the New York City Department of Environmental Protection reported that the bluegill system caught a toxin before it made its way into the water supply. The fish detected a diesel spill a full two hours earlier than any of the other detection devices the agency uses.

San Francisco’s bluegills went on the job a couple of months ago to guard the water supply for more than a million people. Eight bluegills now live deep in the basement of a water treatment plant south of the city, keeping their gills open for substances such as cyanide, diesel fuel, pesticides, and mercury. Susan Leal, general manager of the San Francisco Public Utilities Commission, holds the bluegills in high regard. "It gave us the best of both worlds, which is basically all the benefits that come from nature and the best of high-tech," Leal said. The city plans to install two more tanks soon. "It provides us an added level of detection of the unknown," said Tony Winnicker, a spokesman for the city's Public Utilities Commission. "There's no computer that's as sophisticated as a living being."