The bluegill, pictured above, is a freshwater fish native to, and common in, the eastern United States. They grow, on average, to be four to 12 inches long, and are regularly fried up in a pan for lunch or dinner. If you ask Wikipedia what the bluegill is good for — other than eating, that is — you’ll learn that “bluegills also play an important role in pond and lake management to keep crustacean and insect populations low, as a single bluegill population may eat up to six times its own weight in just one summer.”
The United States Army begs to disagree. To them, the bluegill served a different purpose: a swimming anti-terror device.
In 2006, the Army helped develop a system where sets of eight bluegills, held in captivity, were used as an early warning device against attempts to poison the Washington, D.C., New York, and San Francisco water supplies. The fish are not like bomb-sniffing dogs, however — if anything, they are more akin to canaries in the proverbial coal mine. Each group of fish is placed in small, individual cubbies equipped with piped-in water from the water supply, and each of these slots is outfitted with electrodes that monitor the fish’s behavior and movement. If six or more of the octet begin to act erratically, the alarm goes off, alerting authorities so they can investigate the water supply further. National Geographic put together a neat little graphic explaining the process.
As reported by The Washington Post, a spokesman for the San Francisco Public Utilities Commission explained why the fish are a useful addition to more standard monitoring systems. And don’t worry about the well-being of the fish (except, of course, when they’re poisoned). They are only held in captivity for a few weeks before other fish replace them, so this job is not one for life. Besides, the fish need to be happy and calm in order to be useful in the system, as an already agitated fish is certain to trigger false alarms.
To date, no bluegill-thwarted terrorist attacks have been reported to the media.
From the Archives: Redefining Nemo: The simply strange and un-Disney-like reproductive cycle of Nemo and his fellow clownfish.
Related: A wall-mountable fake bluegill…. for $80, for some strange reason. Maybe it doubles as a home security system?