Evaluation of a New Preparation Technique for Flathead Catfish Pectoral Spines
Jeff D. Koch, Tyler J. Stubbs, and Randall D. Schultz
Abstract.—We evaluated precision and processing times of two methods used to prepare flathead catfish Pylodictus olivaris pectoral spines. The first method utilized a bench-mounted sander to remove the portion of the articulating process traditionally cut using jeweler’s or low-speed saws. Age estimates and processing times of structures prepared with this method were compared to those of conventional basal recess sections of the pectoral spine. The two methods produced structures with equally precise age estimates; however, exact agreement between structures from the same fish prepared using the two methods was only 41%. When age estimates of the two methods did not agree, basal recess sections were generally assigned older ages than articulating processes. This difference was likely due to failure to detect the first annulus on articulating process sections. Preparation time was similar, although readers noted that more effort was needed to age and manipulate articulating process samples under the microscope. In addition, both readers agreed that basal sections were generally more readable than articulating processes. If sanding of articulating processes is used as a spine preparation method, caution should be used to avoid sanding too far into the central portion of the process that contains annuli from early years of life.