TY - JOUR TI - Hydrodynamic model of fish orientation in a channel flow AU - Porfiri, Maurizio AU - Zhang, Peng AU - Peterson, Sean D A2 - Seminara, Agnese A2 - Walczak, Aleksandra M VL - 11 PY - 2022 DA - 2022/06/06 SP - e75225 C1 - eLife 2022;11:e75225 DO - 10.7554/eLife.75225 UR - https://doi.org/10.7554/eLife.75225 AB - For over a century, scientists have sought to understand how fish orient against an incoming flow, even without visual and flow cues. Here, we elucidate a potential hydrodynamic mechanism of rheotaxis through the study of the bidirectional coupling between fish and the surrounding fluid. By modeling a fish as a vortex dipole in an infinite channel with an imposed background flow, we establish a planar dynamical system for the cross-stream coordinate and orientation. The system dynamics captures the existence of a critical flow speed for fish to successfully orient while performing cross-stream, periodic sweeping movements. Model predictions are examined in the context of experimental observations in the literature on the rheotactic behavior of fish deprived of visual and lateral line cues. The crucial role of bidirectional hydrodynamic interactions unveiled by this model points at an overlooked limitation of existing experimental paradigms to study rheotaxis in the laboratory. KW - lateral line KW - rheotaxis KW - vortex dipole KW - organism: fish JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -