Comparison of Pulsed Gastric Lavage and Acrylic Stomach Tubes for Sampling the Diet of Butterfly Peacock Bass

Nonlethal techniques for sampling the stomach contents of fishes have been developed for a variety of fish species. The goal of this study was to determine whether pulsed gastric lavage or acrylic stomach tubes were more effective for extracting stomach contents from Butterfly Peacock Bass Cichla ocellaris, specifically which was least injurious, retrieved the greatest percentage of stomach contents, and was least biased. Pulsed gastric lavage was less injurious than stomach tubes, with bruising of the stomach wall the most common injury being observed. The mean percent of stomach contents removed by pulsed gastric lavage (70.0%) was greater than the percent removed by stomach tubes (57.2%). Both gears were less successful at removing contents from larger fish and had difficulties retrieving contents from fuller stomachs. Pulsed gastric lavage is the recommended method for sampling stomach contents from Butterfly Peacock Bass, as it is both less injurious and more effective than stomach tubes. However, given the low average percent of diet recovered, pulsed gastric lavage may be more appropriate for studies that require only the presence or absence of a species in Butterfly Peacock Bass diets rather than for studies that require quantitative depictions of diet composition. Received December 19, 2015; accepted March 10, 2016 Published online June 24, 2016