Smallest-Ever Acoustic Transmitter with Advanced Battery Improves Juvenile Fish Tracking and Analysis

In 2020, PNNL completed its Eel/Lamprey Tag Development project to miniaturize its Juvenile Salmon Acoustic Telemetry System  technology. The project represents a major step forward in the ability to more safely and accurately study the migratory patterns of aquatic species of concern. Using a novel microbattery to develop a tag small enough to specifically monitor juvenile eels and lampreys, the tag will also apply to many other small fish species or juveniles throughout the United States.

Once abundant throughout all tributaries of rivers flowing into the Atlantic Ocean and upstream through the St. Lawrence River to Lake Ontario, American eels are facing dramatic population declines, ranging from 50% to 90% across various locations. Because dams may impede the migration patterns of eels and fragment and/or reduce available habitats, understanding the impacts of hydropower and providing effective mitigation and passage are necessary for managing eel populations. In addition to the American eel, in the Columbia River Basin, the Pacific lamprey population—a valuable cultural and ecological resource for Native Americans—has severely declined in the past 40 years.

PNNL’s work sought to design, prototype, and perform lab and field tests of an acoustic micro transmitter to study the behavior and survival of juvenile eels and lampreys, and to ultimately provide researchers with an improved tool for understanding migration routes and timing, habitat use, and hydropower dam survival rates for species of concern. PNNL’s project team, consisting of researchers from the lab, government organizations, tribes, and state agencies, developed a miniature monitoring device—the smallest acoustic transmitter in the world—to implant into fish to better understand their movement through hydropower dams. The resulting tag, which was surgically placed in the body cavity of the species, is capable of transmitting data over relatively long distances and tracking 3D positions of fish as they move through streams. During the 38-day study, there were zero fatalities as well as minimal tag losses. Researchers also concluded that for both species, the implantation created no significant change to swimming ability

The next phase of the project is focused on providing the eel/lamprey tag tool and related protocols to the hydropower community that will enable new sensitive species monitoring. In June 2020, the project was selected to receive funding under the Technology Commercialization Fund to optimize the tag design with enhanced firmware, improving frequency accuracy, acoustic signal strength, and reducing the size of the transmitter; optimizing and commercializing the devices’ microbatteries by conducting two trial runs of battery production; and developing an advanced manufacturing process for the transmitter.

For additional information, contact TJ Heibel.