Infrared fish passage counter tested

Yellow perch (Credit: USDA, via Wikimedia commons)

Researchers found mixed results when testing an infrared fish scanner to monitor fish movement through man-made passages in southeast Australia’s Murray Darling Basin, according to the journal Ecological Management and Restoration.

A team from the New South Wales Department of Primary Industries tested the Vaki Riverwatcher in the field and laboratory.  They wanted to evaluate the performance of the unit in varying levels of turbidity. The infrared scanning unit was also compared to more common sonar fish monitors and a fish trap.

They found that in high turbidity levels fish counts were underestimated, while in low turbidity levels fish counts were overestimated. The Vaki Riverwatcher also underestimated fish size.

Despite these initial limitations, the team reported that the instrument could be a valuable tool once dialed in.

Image: Yellow perch (Credit: USDA, via Wikimedia commons)