New acoustic telemetry system helps explain salmon migration

Washington, January 10 (ANI): A new acoustic telemetry system is helping to explain salmon migration, by tracking the migration of juvenile salmon using one-tenth as many fish as comparable methods.

The Juvenile Salmon Acoustic Telemetry System (JSATS) estimated the survival of young, ocean-bound salmon more precisely than the widely used Passive Integrated Transponder (PIT) tags during a 2008 study on the Columbia and Snake rivers.

"Fisheries managers and researchers have many technologies to choose from when they study fish migration and survival," said lead author Geoff McMichael of the Department of Energy's Pacific Northwest National Laboratory.

"JSATS was specifically designed to understand juvenile salmon passage and survival through the swift currents and noisy hydroelectric dams on the Columbia River," he added.

JSATS is an acoustic telemetry system that includes the smallest available acoustic transmitting tag, which weighs 0.43 grams.

Its battery-powered tags are surgically implanted into juvenile salmon and send a uniquely coded signal every few seconds.

Receivers are strategically placed in waterways to record the signal and track when and where tagged fish travel.

A computer system also calculates the precise 3-D position of tagged fish using data gathered by the receivers.

PIT tags are also implanted into juvenile salmon for migration and survival studies, but don't use batteries to actively transmit signals.

Instead, PIT tags send signals when they become energized while passing by PIT transceiver antennas.

In a case study, researchers implanted 4,140 juvenile Chinook salmon with both JSATS and PIT tags.

They also placed just PIT tags inside another 48,433 juveniles.All of the case study's tagged fish were released downstream of Lower Granite Dam on the Snake River in April and May 2008.

A significantly greater percentage of JSATS tags were detected than PIT tags, the case study demonstrated.

For example, about 98 percent of JSATS-tagged fish were detected at Ice Harbor Dam on the Snake River. About 13 percent of PIT-tagged fish were detected in the same stretch of river.

As a result, studies using JSATS require using roughly one-tenth as many fish as those employing PIT tags, which helps further conserve the salmon population.

"JSATS has helped us get a clearer, more complete picture of how salmon migrate and survive through the Columbia and Snake rivers to the Pacific Ocean," McMichael said. (ANI)