Reliability of fish size estimates obtained from a multibeam imaging sonar

Multibeam imaging sonars have considerable potential for use in fisheries surveys because the video-like images are easy to interpret and contain information about fish size, shape, and swimming behavior, as well as characteristics of occupied habitats. We examined images obtained using a DIDSON multibeam sonar for Atlantic sturgeon Acipenser oxyrinchus, striped bass Morone saxatilis, white perch M. americana, and channel catfish Ictalurus punctatus of known size (20 - 141 cm) to determine the reliability of length estimates. For ranges up to 11 m, percent measurement error (sonar estimate - total length)/total length X 100 varied by species but was not related to the fish's range or aspect angle (orientation relative to the sonar beam). Least-square mean percent error was significantly different from 0.0 for Atlantic sturgeon (x ̅=-8.34, SE=2.39) and white perch (x ̅=14.48, SE=3.99) but not striped bass (x ̅= 3.71, SE=2.58) or channel catfish (x ̅=3.97, SE=5.16). Underestimating len...

多波束成像声呐（multibeam imaging sonars）在渔业调查中具备极高应用潜力，因其成像效果类视频影像，易于解译，且可提供鱼类体型、形态、游动行为以及栖息生境特征等相关信息。本研究使用DIDSON多波束声呐获取的影像，针对已知体长为20~141 cm的大西洋鲟（*Acipenser oxyrinchus*）、条纹狼鲈（*Morone saxatilis*）、白鲈（*M. americana*）以及斑点叉尾鮰（*Ictalurus punctatus*）开展分析，以评估体长估算结果的可靠性。在探测距离不超过11 m的情况下，测量误差百分比（声呐估算体长 - 实际总体长）/实际总体长 ×100 因物种而异，但与鱼类的探测距离及方位角（相对于声呐波束的朝向）无显著关联。大西洋鲟（最小二乘平均误差百分比均值为-8.34，标准误SE=2.39）与白鲈（均值为14.48，SE=3.99）的该指标显著异于0，而条纹狼鲈（均值为3.71，SE=2.58）与斑点叉尾鮰（均值为3.97，SE=5.16）的误差则未呈现显著偏离。对体长的低估……