Fish Protects Water Supply

A number of North American cities are using common bluegills, fish particularly sensitive to chemicals in their environment, to monitor the quality of drinking water. An Associated Press report explains: “The fish are kept in tanks constantly replenished with water from the municipal supply, and sensors work around the clock to register changes in the breathing, heartbeat and swimming patterns of the bluegills that occur in the presence of toxins.” In one instance in New York City, says the report, “the fish noticed a diesel spill two hours earlier than any . . . other detection devices,” and they thus prevented toxins from reaching the public water supply.