Earmarked – Barcoded Fish, Bees & People

by Amy Anderson

www.informationmag.com – The words "barcoded fish" may sound like the punchline to a surrealist joke, but fisheries are already producing millions of biologically engineered scaly critters that one day could be as scannable as a can of soup, and the tracking technology is rapidly moving up the food chain.

Scannable fish are the product of teamwork between eager ichthyologists and Intermec, a manufacturer of automated data collection systems and supplies that has modified commercial barcode symbology. The company hasn’t stopped at fish, however, and their living subjects range in size from bees to humans.

By barcoding fish, scientists can trace the hatcheries and sub-units of hatcheries from which fish originate, using the "space available on a fish" as a "very efficient way to organize information," says Eric Volk, a researcher who helped develop the method at the Washington Department of Fish and Wildlife.

The technique allows commercial hatcheries to study the effects of pollution and habitat damage on survival rates in the wild, Volk says. He estimates that between 25 million and 40 million fish in Washington State and up to 400 million fish in Prince William Sound, Alaska, plus others as far away as France and Japan, are marked every year by a system of bars and spaces encoded in their bodies.

These bar codes, which resemble the rings in a tree trunk, are calcified elements in the ears of fish, called otoliths. They grow by the accumulation of daily layers, visible under a microscope as a series of concentric rings. Because these rings are extremely sensitive to thermal changes, a sudden drop in water temperature will cause the layer produced that day to appear much darker than its neighbors. A series of such events while the fish are in the hatchery results in a distinct pattern that lasts a fish’s entire lifespan.

That lifespan ends when the subjects are killed to extract and read the coded calcifications. The "million-dollar question," as Volk puts it, is how to devise a marking system that works without killing the fish, so that larger samples of any hatchery group can be collected, thus increasing the statistical significance of the studies.

One marked advantage of the current technique, however, is that it is relatively inexpensive: all that’s needed is a temperature-controlled pond. Draw-backs include pesky power outages and forgetful scientists who neglect to change the temperature of the water at the appropriate time, Volk says.

As part of a study carried out from 1987 to 1993, Volk worked with Intermec scientist Sprague Ackley to mark an initial batch of approximately two million salmon at the Cowlitz Hatchery in Washington State over a period of 14 days. After a month, they snagged a sample of fish, removed the otoliths and viewed them under high magnification to reveal the encoded bands. Readings by laser devices are possible but can be less reliable than the human eye, which has been the instrument of choice so far.

Eccentric as the concept may seem, this is not Intermec’s first foray into the barcoding of small creatures. In 1989, Intermec also worked with the U.S. Department of Agriculture’s Carl Hayden Bee Research Center in Tucson, Arizona to develop a system to track the movements of honey bees. Stephen Buchmann, the entomologist who carried out the project, was in line at the supermarket when the idea struck to glue bar codes to bees’ backs. He contacted Intermec and began working with Ackley to create a barcode label small enough to fit on the thorax, a space about one-tenth of an inch wide, and light enough not to interfere with the bee’s normal movements.

By using only 9 to 11 stripes, rather than the 55 stripes found on most commercial products, Intermec came up with perhaps the world’s smallest functioning bar code, no bigger than a newborn baby’s fingernail and weighing less than 20- millionths of an ounce.

Buchmann and his associates subdued the bees with a combination of refrigeration and carbon dioxide and then dabbed common shellac on each bee’s thorax, where a barcode label was pressed into place. Once the bar codeswere applied, a laser reader at the hive’s opening recorded each bee’s entrance and exit.

While barcoding critters makes for an interesting sideline, there is no reason the same idea cannot be used on humans – and it is. Intermec has applied barcode technology to track runners at the Boston Marathon,  attendees at the Sundance Film Festival and participants in the most recent U.S. presidential inauguration. Christine Goetz, Intermec’s public relations manager, says it can also be used in offices and factories, where barcoded badges are scanned at doorways to track a worker’s arrival and departure times.

For employers looking for more workplace control, is it harder to track workers than worker bees? According to Goetz, it’s "functionally the same thing."

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