Measurement of Diurnal Body Tilt Angle Distributions of Threeline Grunt Parapristipoma trilineatum Using Micro-Acceleration Data Loggers

Abstract

The body tilt angle of a fish has a large effect on the acoustic target strength. For an accurate estimation of fish abundance using acoustic methods, it is necessary to measure body tilt angles in free-ranging fish. We measured diurnal body tilt angle distributions of threeline grunt (Parapristipoma trilineatum) while swimming in schools in a fish cage. Micro-acceleration data loggers were used to record (for 3 days) swaying and surging accelerations (at 16 Hz intervals) of 10 individuals among 20 forming a school in a fish cage. Time series analysis of 1-h mean body tilt angles revealed significant differences in body tilt angles between day (−7.9 ± 3.28°) and night (0.8 ± 5.89°), which must be taken into account when conducting acoustic surveys. These results will be useful for calculating

Measurement of Fish Habitat Use by Fish-Mounted Data Loggers for Integrated Coastal Management: An Example of Japanese Sea Bass (Lateolabrax japonicus) in Tokyo Bay

“…Recently, data loggers and a micro-underwater video camera have become small enough to be attached to small fi sh to measure acceleration, water temperature, depth, and conductivity (e.g., Alabsi et al 2011 ;Komatsu et al 2011 ;Tanoue et al 2013 ;Kudo et al 2007 ). The acceleration sensor measures the intensity of swimming behavior and the number of active burst events by fi sh such as feeding (e.g., Tanoue et al 2012 ).…”