Recent research by a team led by Jonathan Cox and Zhijin Wang shows how water flows through the nose of a guitarfish, a type of ray. The team discovered that vortex-like structures in their noses help the guitarfish to swim and smell more efficiently. This is the first time that vortex-like structures have been found in a fish's nose.
Smell is important for fish. Their ability to pick up scent depends on the movement of water. Some fish get water moving through their nose by breathing, others by swimming.
The team discovered that guitarfish move water through their nose by swimming and breathing. The movement by swimming is helped by nasal flaps.
These nasal flaps create regions of high and low pressure. Vortex-like structures resulting from the pressure difference may encourage water flow through the nose. This may make the guitarfish smell—and swim—more efficiently.
The vortex-like structures in the guitarfish's nose may be similar to the vortex rings associated with aircraft wings. These vortex-like structures caused by air circulating near the wing enable planes (and birds) to fly.
Explore further: Researchers analyze Lagrangian coherent structures in water around swimming fish
Mawuli P.K. Agbesi et al. Complex flow in the nasal region of guitarfishes, Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology (2016). DOI: 10.1016/j.cbpa.2015.12.007