When thinking of migrating fish, most people’s minds fill with images of majestic salmon vaulting themselves over waterfalls. Few conjure thoughts of the American eel and Pacific lamprey. Although unglamorous, eels and lampreys play a pivotal role in the health of oceanic and riverine ecosystems.
Pacific lamprey spend the majority of their lives in fresh water rivers, migrating out to the Pacific Ocean as juveniles only to return a year or two later as adults to spawn. Adult American eels, on the other hand, migrate to the Atlantic Ocean to spawn with juvenile eels returning inland. For both, hydropower dams impede their routes.
To better study the interesting and extraordinarily long lives of these species and others, Pacific Northwest National Laboratory (PNNL) researchers have developed two new acoustic telemetry tags, including one micro tag that is small enough to be used to study the behavior of juvenile fishes like eel and lamprey. The other tag is designed for long-lived sturgeon to allow for over 365 days of monitoring! These new models of fish tags use the Juvenile Salmon Acoustic Telemetry System (JSATS) technology in a new way. These tags send acoustically transmitted signals that can be detected by receivers deployed in rivers and other waterways, with the sturgeon tag able to be detected up to fish that are 500 meters away—perfect for fish like sturgeon and adult eels that live deep underwater. Furthermore, both tags have longer lifetimes than most other tags of the same size on the market, which is also a good match for studying many sensitive species.
Since 2001, with funding from the the U.S. Department of Energy’s Wind and Water Power Technologies Office and the U.S. Army Corps of Engineers’ Portland District, PNNL researchers have increased the JSATS tag’s sophistication by decreasing size and improving the signal life to create overall more effective fish tracking technologies. All JSATS fish tags release quiet beeps that are picked up by receivers placed in rivers, lakes, and other water bodies as tagged fish swim by. Receiver data helps researchers map out the precise 3-D location of each fish and determine habitat use, behavior, and if fish are injured during their travels. This information helps make dams more fish-friendly by providing insights that utilities can use to revise hydropower operations or alter structures like fish ladders to make them more effective. Over the years, hundreds of thousands of young fish have been studied with JSATS tags