The aquarium was planning to build a seal, penguin and sea otters exhibit, but the plans have been shelved. According to Merlin Entertainment - the aquarium's parent company - the plans were put on hold due to the peak season coming to an end, but animal rights groups believe the U-turn is down to them.
For five months protesters camped outside the Sea Life Centre every weekend to campaign against the plan, asking for signatures and handing out leaflets.
Bernard Howells of Clifton Architects, said: 'The aquarium has peak and low seasons, and due to planning delays, it was deemed to be in the centre's best interest to wait until the exhibit would be ready for the next peak season.'
Despite these claims, animal rights activist Lisa Gooch has said publicly that the change in plans was down to the campaign and its overwhelming public support.
In response, Merlin Entertainment stated that it has never been and never will be influenced by any such pressure.
A Merlin spokesman said: 'The protests were generally low key; there was only one incident where a protester managed to get into the centre, demanding to see the manager. He jostled a visitor and was quickly removed, but that was the only real incident - there was no 'extremist' action.'