Fish Handling and Ultrasound Procedures for Viewing the Ovary of Submersed, Nonanesthetized, Unrestrained Channel Catfish

Abstract This study addressed the development of rapid, straightforward, and minimally stressful procedures for the ultrasound imaging of ovaries of channel catfish Ictalurus punctatus in a commercial hatchery setting. The objectives were to (1) describe the ultrasound imaging equipment and settings used, (2) describe the fish handling procedures during imaging, and (3) illustrate image orientation with respect to the physical positioning of the probe and the catfish. Ultrasound images of the ovaries of channel catfish were recorded as digital video recordings (audio video interleave format) and as still images (ultrasound image format files). This study integrated the use of nonanesthetized, submersed fish within a recirculating tank system or portable container and a submersed waterproof probe, which enabled us to use water as a transmission medium for ultrasound. This allowed us to image the fish in ventral recumbency (upright swimming position) without using a physical restraint in the tank system, or...