Fig. 4.

Efficiency is affected by catch percentage and energy use as shown in Fig. 3. (A) At high speeds, efficiency drops sharply if whales open their mouths too early. Efficiency is increased for moderate speeds when the flippers are used to scare early fleeing fish back toward the mouth. (B) The timing of the MO in relation to the school has a much greater effect on efficiency than the timing in relation to peak speed. (C) At slow speeds, the timing of engulfment is less critical as efficiency can remain high.