Why would tidal ventilation not work well in migratory fish?

• Tidal ventilation is when air leaves and enters through the same route
• Tidal volume is amount of air usually breathes in and out
• In birds ventilation is a flow through system; it has numerous air sacs that expand when an bird inhales and shrinks when it exhales
• In avian systems, air entering through the trachea and then bronchi go into parallel air tubes called parabronchi that make up the longs; they have enormous SA and network capillaries; blood flows through in a crosscurrent direction and is less efficient than counter but more than tidal vent