PNNL

Abstract

The Juvenile Salmon Acoustic Telemetry System, developed by the U.S. Army Corps of Engineers, Portland District has been used to monitor the survival of juvenile salmonids passing through hydroelectric facilities in the Federal Columbia River Power System. Cabled hydrophone arrays deployed at dams receive coded transmissions sent from acoustic transmitters implanted in fish. The signals’ time-of-arrival data on different hydrophones is used to track fish in three dimensions. In this article, a new algorithm that decodes the received transmissions is described and the results are compared to results for the current decoding algorithm. In a laboratory environment, the new decoder was able to decode signals with lower signal strength than the current decoder. In field testing, the new algorithm decoded significantly more signals than the current decoder and three-dimensional tracking experiments showed that the new decoder’s time-of-arrival estimates were accurate. For each distance, the new algorithm tracked more points more accurately compared to current decoder. The new algorithm was also more than 10 times faster, which is critical for real-time applications and an embedded system.