Open AccessLife in the flow: unique adaptations for feeding on drifting zooplankton in garden eels
Author(s) -
Alexandra Khrizman,
Gal Ribak,
Dmitri Churilov,
Irena Kolesnikov,
Amatzia Genin
Publication year - 2018
Publication title -
journal of experimental biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.367
H-Index - 185
eISSN - 1477-9145
pISSN - 0022-0949
DOI - 10.1242/jeb.179523
Subject(s) - zooplankton , predation , drag , burrow , fishery , underwater , flow (mathematics) , ecology , current (fluid) , habitat , water flow , oceanography , environmental science , biology , geology , physics , mechanics , environmental engineering
A major challenge faced by sessile animals that feed in the flow is to maintain effective feeding postures while enduring hydrodynamic forces. Garden eels exhibit an exceptional lifestyle: feeding on drifting zooplankton while being “anchored” in a burrow they dig in the sand. Using underwater observations, sampling and 3-D video recording, we measured the feeding rates and characterized feeding postures of garden eels under a wide range of current speeds. We show that the eels behaviorally resolve the tradeoff between adverse biomechanical forces and beneficial fluxes of food by modulating their body postures according to current speeds. In doing so, the eels substantially reduce drag forces when currents are strong, yet keep their head well above bottom in order to effectively feed under conditions of high prey fluxes. Those abilities allowed garden eels to become one of the rare oceanic fishes that live in sandy, predation-rich habitats and feed on zooplankton while being attached to the bottom.