210. When using a recording depth finder in the open ocean, what phenomena is most likely to produce a continuous trace that may not be from the actual ocean bottom?

Echoes from a deep scattering layer produce a continuous trace resembling a false bottom on a recording depth finder. This layer, composed of marine organisms, reflects sound and appears as a distinct, horizontal line above the actual seabed. Other phenomena, such as multiple returns, fish schools, or transducer placement issues, generate irregular or surface-related signals, not a continuous false bottom trace.