self-proclaimed activist told local TV station KENS.
Shannon said he grew concerned about the welfare of the animals at the aquarium after a friend told him that the marine life was dying frequently due to poor conditions.
Having three decades worth of experience with marine life, he decided to act.
First, he went to investigate the conditions at the aquarium by posing as a salt distributor, the New York Post noted.
Then on Saturday he returned to monitor the situation but, when he saw a guest squeeze the shark in the interactive touch pool, he intervened.
"Then I pulled the net out, I told the customers to get out of the way, ‘I'm going to quarantine the shark,’" he told KENS. "I'm an activist, not a criminal, and basically I don't want to produce any crimes that will make me lose my family or big charges and to open an eye and make things better."
The aquarium addressed Shannon's comments in a statement, noting that "any deceased animals he may have seen while in our back areas were an unfortunate part of being in this business."
Aquariums and marine parks have been facing mounting pressure from activists who oppose animals in captivity.
People for the Ethical Treatment of Animals has rigorously campaigned against interactive touch pools and "swim-with" programs at such facilities, stating that they "invade the animals’ already diminished worlds and are intrusive, stressful, and even dangerous for the animals, as well as being risky for human participants, too."
The organization noted that animal petting pools "are frequently exposed to foreign bacteria and other pathogens, and they can become anxious, frustrated, aggressive, and even neurotic as a result of being confined to shallow tanks and exposure to constant interaction with humans."
For these reasons, an online petition has been launched on Care2.com, asking the San Antonio Aquarium to close its touch pool.