Assessing the Injury Rates of Fishes Using Established Boat Pulsed-DC Electrofishing Protocols

Fisheries research conducted from 1960-1990 supports a general consensus that pulsed-DC electrofishing injures less fishes than AC electrofishing. Much of this research focused on salmonids. More recent non-salmonid studies suggest pulsed-DC electrofishing can cause significant injuries to fishes. Controlled laboratory studies using bluegill, channel catfish, black crappie, and largemouth bass have reported injury rates between 0-50% and 0-45% for hemorrhaging and spinal injury, respectively. Studies assessing injury rates in the field are infrequent. In preliminary research, we found a spinal injury rate of 55% for silver carp collected with boat pulsed-DC electrofishing. With the extensive use of pulsed-DC electrofishing it is important to determine if this high rate of spinal injury is exclusive to silver carp, size specific, or unique certain to electrofishing settings. We will address these questions using fishes collected through two standardized boat pulsed-DC electrofishing protocols: 1) the Long Term Resource Monitoring Program and 2) the Long Term Illinois, Mississippi, Ohio, and Wabash River Fish Study funded through the Federal Aid in Sport Fish Restoration Program. Specifically, we will euthanize and necropsy bluegill, channel catfish, largemouth bass, silver carp, gizzard shad, freshwater drum, and common carp to test for spinal fracturing or hemorrhaging.