Acoustic fish tags have revolutionized salmon science, allowing biologists to track the movements of salmon from spawning streams to the ocean.
But the technological challenge has been to create tags small enough to insert into salmon when they are smaller, younger fish. Since salmon’s early lives take place in small streams at the headwaters of the Pacific Northwest’s mighty rivers, tracking their movements is important to learn what truly matters for the species’ success.
Now scientists at the Department of Energy’s Pacific Northwest National Laboratory have created a microbattery that holds twice the energy compared to current microbatteries. The new battery not only can make the tags smaller, but also can power signals over longer distances – allowing researchers to track fish further from shore, from dams or deeper in the water.
The battery, slightly larger than a long grain of rice, is not the world’s smallest battery (some are tinier than the width of a human hair). But those smaller batteries don’t hold enough energy to power acoustic fish tags.
The new battery is small enough to be injected into a salmon and holds much more energy than similar-sized batteries.
“The invention of this battery essentially revolutionizes the biotelemetry world and opens up the study of earlier life stages of salmon in ways that have not been possible before,” said M. Brad Eppard, a fisheries biologist with the U.S. Army Corps of Engineers.