The perception of fish locomotion is important for understanding their adaptive behaviors and ethological characteristics. However, the main strategy used for extracting fish attitudes involves the use of a vision-based monitoring system, which is limited in its range of observation and cannot perform tracking for long times. Here, we report the use of a wearable tagging electronic device, referred to as an underwater vest, to capture the surrounding flow field disturbances triggered by swimming or momentary postural changes. All of these goals were achieved by integrating a pair of pseudocapacitive pressure-sensing units and a flexible circuit board. Notably, additional conditions, such as variable hydraulic pressures and minimal changes in fish posture, require high stability and sensitivity of the sensing units. Thus, hybrid hydrogel electrodes were developed through cross-linking MXene with holey-reduced graphene oxide nanosheets and further modification with 1-ethyl-3-methylimidazolium dicyanamide ionic liquids, which increased the interfacial capacitance and long-term interfacial activity of the MXene. Consequently, the sensing unit exhibited ultrahigh sensitivity (S_max~136,207 kPa⁻¹) in an aquatic environment for 60 days and superior high-pressure resolution (10 Pa) within a wide working range of 1 MPa. Ultimately, an underwater vest integrated with such sensing units clearly distinguished and recorded fish locomotion. We believe that the designed device may open avenues in flow field monitoring and ocean current detection and provide new insights into the development of sensitive underwater tagging.

鱼类运动的感知对于理解其适应性行为和行为学特征非常重要。然而，提取鱼类姿态的主要策略是使用基于视觉的监测系统，该系统的观察范围有限，无法进行长时间跟踪。在这里，我们报告使用可穿戴标签电子设备（称为水下背心）来捕获由游泳或瞬时姿势变化引发的周围流场扰动。所有这些目标都是通过集成一对赝电容压力传感单元和柔性电路板来实现的。值得注意的是，额外的条件，例如可变的液压和鱼姿势的最小变化，需要传感单元的高稳定性和灵敏度。因此，通过将 MXene 与多孔还原氧化石墨烯纳米片交联，并用 1-乙基-3-甲基咪唑鎓二氰胺离子液体进一步修饰，开发了混合水凝胶电极，从而增加了 MXene 的界面电容和长期界面活性。因此，传感单元在水生环境中表现出超高灵敏度（S _max ~136,207 kPa ^-1）60天，并在1 MPa的宽工作范围内表现出卓越的高压分辨率（10 Pa）。最终，集成了此类传感单元的水下背心可以清楚地区分并记录鱼类的运动。我们相信，所设计的设备可以为流场监测和洋流检测开辟途径，并为敏感水下标记的发展提供新的见解。