An Introduction to Hydro Acoustic Echo Traces
抄録
This textbook, "An Introduction to Hydroacoustic Echo Traces", explains hydroacoustic information on the recording charts in the form of echo traces, digits and lines. Interpretation of echo traces is one of the most important points of fishing technology : scouting, detecting and catching fish; observation of submerged fishing gear; annual distribution of fish shoals; topographic features of sea-bed; thermal discontinuities; water temperature from surface to sea-bed, etc..