US: Thom Litts and Adam Kaeser from the Georgia Department of Natural Resources have developed a sonar mapping method. It uses relatively low-cost equipment to provide habitat information that helps scientists understand where fish and rare mussel species are spending their time, said Stephen Golladay, a biologist at the Joseph W. Jones Ecological Center at Ichauway, where Kaeser and Litts refined their technique.
Litts has developed a programme that combines the sonar imagery with GIS coordinates and a widely available mapping programme to create a map of the river showing all the different types of habitat at the river bottom.
In the past, getting this kind of information required a two-member crew travelling down the river, stopping at different points to run a rope across and then walk, swim, snorkel or scuba dive along the rope to visually inspect the bottom, Kaeser said. Between each of these research points, they would have to estimate what the river bottom might look like.
Kaeser and Litts’ research has been prominently published in the journal of the American Fisheries Society. The pair has also trained other state, federal, private and nonprofit professionals in the US and Canada on how to use the technique.
In their paper, Kaeser and Litts estimated that it would take 10 times as long to map the same distance of stream using the traditional method and the results would be less certain.
“This is a great resource for people trying to better manage river flows and river resources in Georgia,” Golladay said.