Journal of Fish and Wildlife Management | 2021
Effects of Training on Side-Scan Sonar Use as a Fish Survey Tool: a Case Study in Alligator Gar
Abstract
Consumer-grade side-scan sonar has become a versatile fisheries management tool.\xa0 First applied to assess habitat, its use has expanded to surveying fishes in recent years.\xa0 However, an important consideration is the skill and experience of users, which can impact both the accuracy and comparability of surveys.\xa0 To this end, we characterized the ability of a small sample of novice users (N = 8) to identify alligator gar Atractosteus spatula in imagery, as well as the effect of a two-hour training exercise on user performance.\xa0 Prior to training, mean accuracy (expressed as the difference between observed and expected counts) among participants ranged from -2.6 to 1.3 fish and precision ranged from ± 1.2 to 2.4 fish, with the majority of participants underestimating the number of alligator gar present in the imagery.\xa0 False positives (i.e., identifying alligator gar in imagery when none were present) were common among participants.\xa0 Post-training mean accuracy ranged from -3.1 to 0 among participants and precision ranged from ± 1.6 to 3.2 fish.\xa0 The frequency of false positives was significantly reduced following training, and participants reported significant increases in confidence associated with image interpretation.\xa0 The relatively high accuracy and precision we observed prior to training indicated that side-scan sonar can be easily incorporated into large-scale fishery monitoring efforts for alligator gar.\xa0 However, our results also suggested that a rather minimal investment in training can further improve consistency and reduce uncertainty among novice users.