Several large chalk boards were hung outside the refrigerator. These boards included schedules of activities for each animal, and listed the amount of food that was to be used to reinforce the animals during each activity. In other words, a trainer couldn't get fed up because a whale was not doing what was asked, and just not feed it the last ten pounds for the day. The animals know that no matter what, they will be fed. Obviously, it is to the trainers' advantage to use the food in a positive way, and they do.
P is play, a time when the trainers and the whales simply play.
The trainers act goofy, play with plush Shamus, mirrors, or radio controlled cars, and the whales can join in as much or as little as they want. There is no right or wrong at play time, everybody has fun. Whales are taught new behaviors, and rewarded when they do the right thing. More about learning in a bit. E is exercise.