Hydrodynamic starvation in first-feeding larval fishes.
Larval fishes suffer prodigious mortality rates, eliminating 99% of the brood within a few days after first feeding. Hjort (1914) famously attributed this "critical period" of low survival to the larvae's inability to obtain sufficient food [Hjort (1914) Rapp P-v Réun Cons Int Explor Mer 20:1-228]. However, the cause of this poor feeding success remains to be identified. Here, we show that hydrodynamic constraints on the ubiquitous suction mechanism in first-feeding larvae limit their ability to capture prey, thereby reducing their feeding rates. Dynamic-scaling experiments revealed that larval size is the primary determinant of feeding rate, independent of other ontogenetic effects. We conclude that first-feeding larvae experience "hydrodynamic starvation," in which low Reynolds numbers mechanistically limit their feeding performance even under high prey densities. Our results provide a hydrodynamic perspective on feeding of larval fishes that focuses on the physical properties of the larvae and prey, rather than on prey concentration and the rate of encounters.
Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel; andThe Inter-University Institute for Marine Sciences, Eilat 88103, Israel.
Victor
V
China
Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel; andThe Inter-University Institute for Marine Sciences, Eilat 88103, Israel holzman@post.tau.ac.il.
Roi
R
Holzman
D000818:Animals; D001696:Biomechanical Phenomena; D017753:Ecosystem; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D005398:Fisheries; D057446:Hydrodynamics; D007814:Larva / Q000254:growth & development / Q000502:physiology; D008297:Male; D009055:Mouth / Q000502:physiology; D009792:Oceans and Seas; D011235:Predatory Behavior / Q000502:physiology; D012403:Rotifera; D021541:Sea Bream / Q000254:growth & development* / Q000502:physiology*; D013217:Starvation / Q000401:mortality* / Q000503:physiopathology*; D014743:Videotape Recording; D014783:Viscosity
biomechanics; larval ecology; stable ocean hypothesis; suction feeding