Corpus Christi, Texas snorkeling ?'s

[miniz2k6]

i plan to make a trip to San Antonio,TX in a few months. while i'm there i plan on going snorkeling for the first time in Corpus Christi. anyone have any hints or tips for a first-timer? how do i go about legally collecting coral? will i be able to collect coral while snorkeling or do i need to dive to be able to reach the depths they are in? thinks in advance!