Basically when you touch the screen the whale tilt up and goes higher, when you don't touch the screen he tilts and goes down.
Other than that an autoscroll based on horizontal speed of the whale.
There's nothing about friction, damping, you don't have environmental elements that influence the whale's movement (Except for the speed burst but it's just speed...) it's just all about simple orientation of speed vector. Maybe some secondary element does use physics, but the whale is definitely not physics driven.
You can emulate the same kind of movement with a simple bullet behavior.