ABSTRACT

The orientation of sea fans and sea pens (Figure 20.1) to the ßow has been attributed to hydrodynamic phenomena without any detailed explanation of the reasons (e.g., Laborel and Vacelet, 1958; Theodor and Denizot, 1965). There are two possible mechanisms through which the natural torque on the fan can cause the population to align with the axis of the dominant ßow.