Wrangell Sentinel -

Most people don’t know that 40 years ago Alaska pioneered the use of sonar to track salmon runs, or that state fishery managers operate 15 sonar sites on 13 rivers from Southeast to the Yukon.

The goal of making Alaskans more aware of one of Alaska’s most important fish counting tools has been accomplished with the launch of new web based project that lets visitors see three types of sonar in action. 

The site explains that traditional tools such as weirs and counting towers can be used to count salmon in clear, narrow streams, but not in wide, turbid rivers.

“To gauge salmon runs w...