Assessment of an Adaptive Resolution Imaging Sonar (ARIS) for fish counting in the Lower Fraser River

In the 2015 field season, the Pacific Salmon Commission’s Stock Monitoring Group leased an Adaptive Resolution Imaging Sonar (ARIS) system for counting fish passage and estimating behaviour and size distributions of salmon species at its hydroacoustic site on the Fraser River near Mission, B.C. The Southern Fund Committee (SFC) provided funding for this experiment, which demonstrated that the ARIS sonar was able to capture high-resolution images of fish targets allowing users to enumerate salmon passage and fish size at the site. As a new generation of imaging sonar, ARIS inherits many core technological features of the Dual-frequency identification sonar (DIDSON) while providing users with greatly enhanced and superior utilities for various needs, which will provide PSC with more accurate and precise estimates of near-shore salmon passage than the current split-beam system can ever achieve.
Sound Metrics Corporation (SMC), the parent sonar manufacturer of ARIS and DIDSON, has started to gradually phase out DIDSONs from the market. The imaging sonar systems are a very important component of the Mission hydroacosutics program, which have improved the accuracy of salmon-flux estimation in near-shore waters. Given the success of the 2015 pilot lease project noted above, the successful regional adoptions of ARIS for salmon enumeration in Alaska and Washington State, and PSC DIDSON units being beyond the manufacturer’s projected lifespan, we propose to modernize the Mission site and implement the ARIS imaging sonar into our daily estimation for the 2016 field program.