LONG BEACH (CBSLA.com) — Hundreds of animal-rights activists protested a proposed major expansion by Sea World in Long Beach on Thursday.

The marine theme park received thousands of hate emails after they announced plans to build new 450,000 gallon tanks and 5.2 million-gallon pools to hold the killer whales.

Demonstrators argued breeding the whales in captivity is not only cruel, but bigger tanks will project more breeding.

“They’ve already said that they’re going to continue the captive breeding program,” explained David Hance of the Sea Shepherd Conservation Society. “They’ll breed more in captivity as well as bringing in others from the wild.”

The California Coastal Commission late Thursday approved the $100 million proposal, called the Blue World Project, but prohibited breeding of captive orcas. The commission’s approval also comes with the provision that no new whales from the wild will be kept there.

Sea World officials said they did not support these restrictions and left the room after the vote, CBS2/KCAL9 reporter Jasmine Viel reported.

PETA brought in actress Pamela Anderson to persuade commissioners to vote against the proposed plan.

“This is another pathetic attempt to make money off of vulnerable whales,” added Anderson. “Everybody knows they’re not happy in their tanks.”

According to Sea World, the whale population at their San Diego facility will not significantly increase with the project expected to be completed by 2018.