Source Texts
Text
Water flowing around an obstruction creates vortices (swirls) that vary in size with the obstruction's size and position, and fish sense these vortices to navigate around the obstructions. Using models of three fish-head shapes-narrow (low ratio of width to length), intermediate, and wide (high ratio of width to length)- Yuzo R. Yanagisuru, Otar Akanyeti, and James C. Liao showed that as vortex size increases, pressure fluctuations at the snout increase for narrow-headed fish but remain low for wide-headed fish. A second research team has therefore hypothesized that in low visibility, a fish will be more likely to avoid an obstruction when the associated pressure fluctuations at the fish's snout are greater.