Abstract
Many types of suspension-feeding plankton larvae produce one or more, up to 1 cm long mucous strings. These function as drift anchors by increasing hydrodynamic drag. This effect, together with gravitational forces, allows the larvae to remain almost motionless relative to the undisturbed water column while feeding. Larvae that are essentially tethered in the water column enhance their efficiency of suspension feeding by a factor of 1.5–2 relative to larvae that translate through the water. The reason for this is that the flow fields surrounding the animals are different in the two situations. This effect is demonstrated in two kinds of veliger larvae.