Assessment of Field Gastric Lavage Efficacy: Salmo salar

• Main Author: Kowalik, Dave
• Format: Text
• Language: unknown
• Published: Digital Commons @ ESF 2016
• Subjects: Atlantic salmon; Salmo salar; Aquaculture and Fisheries; Rock Creek
• Online Access: https://digitalcommons.esf.edu/honors/85; https://digitalcommons.esf.edu/cgi/viewcontent.cgi?article=1088&context=honors

Post-mortem dissection (gastric) was performed on juvenile Atlantic salmon Salmo salar ranging from 52 mm to 104 mm in total length (tip of snout to end of tail) and weighing 1.04 g to 9.42 g to assess the efficacy of gastric lavage conducted in the field (Kennedy and Strange 1981). Little Creek, Rice Creek, Eight Mile Creek, Point Rock Creek, and Furnace Creek served as the sampling sites (all located in New York). The size, and quantity of recovered food items were compared between field lavage contents and laboratory dissection contents. Macroinvertebrates were extracted from the buccal region, gill rakers, esophagus, and stomach of Salmo salar and then identified to determine the most numerous orders, breadth of dietary items consumed, the mean length of ingested contents (excluding cerci and antennae), and field lavage efficiency. The most abundant order collected from field lavage was Ephemeroptera at 279 individuals and the most abundant order collected from post-mortem dissection was Diptera at 23 individuals. The mean length of food items recovered in the field via gastric lavage was not significantly different from the mean length of food items extracted via post-mortem dissection. Field lavage was performed with 90.93% efficiency when accounting for all of the sampling sites combined. 70.45% of the fish sampled had all of their stomach contents extracted successfully in the field.