The punch card is for feeding the stingrays, sharks, and seals/sea lions. You can get the punch card at the feeding both for any of those 3. On 03/22/11, the stingray and seals/sea lions feeding booths were open as soon as the park was open. You could walk right up to either one and get the punch card.
The shark feeding booth didn't open that early. It was supposed to open at 11:15. Once it was open, you could walk right up and get the punch card.
The dolphin feeding is a different story. The dolphin area didn't open until 10:00. You feed the dolphins at selected times. The feeding booth is closed until a short time before each scheduled feeding time. A long line will form.
I don't know if they sell the punch card at the dolphin feeding booth. But even if they do, you don't want to wait in that line to get it. And you don't want to wait until that window happens to be open to get it. Get it at one of the other three booths.
I highly recommend feeding all of them. It was so much fun.
I also recommend getting in the guest relations line when you get to the park and asking when the feeding booths will be open. Hopefully they can tell you. I walked all the way back to the shark area at 9:30 only to learn that it wasn't open until 10:00. Then I walked back at 10:00 only to find that the feeding booth wasn't open. I waited in the restaurant reservation line, and that lady was the one who told me it wouldn't be open until 11:15.
The dolphin feeding booth has a sign telling you when the next scheduled feeding time is, but it does not list all of the feeding times for the day.