For the ocean’s most powerful predator, killer whales are surprisingly weak.

SeaWorld’s new chairman and chief executive insists that its captive orcas — better known as killer whales — would get sick and die if released into ocean sanctuaries.

“More than 80 percent of our whales were born in our care, and sea pens would be a poor choice for them,” CEO Joel Manby told shareholders on Wednesday at SeaWorld’s annual meeting.

“Uncontrollable exposure to pollution, ocean debris and life-threatening pathogens in ocean waters are just a few of the factors that make sea pens an unhealthy living environment for any of our animals.”

Manby, who took the helm on April 7, was responding to a question about whether the company had the scientific capabilities and knowledge to relocate animals to sea pens.

The chain of marine parks is under pressure to stop its killer whale shows after a damaging documentary, called “Blackfish,” accused the company of mistreating the animals. The backlash damaged the company’s reputation, along with park attendance and the stock price.

Animal activist group PETA, in particular, is waging an intense campaign and is calling on the company to create seaside sanctuaries for the whales.

Marine-animal expert Jean-Michel Cousteau — who worked on the successful release of Keiko, the star of “Free Willy,” into a seaside pen (before he died in the wild) — said it is possible to keep orcas in such an open area.

“The problem I have with SeaWorld is they are looking for all kinds of excuses to keep doing what they are doing,” said Cousteau, who is not affiliated with PETA.

For its part, SeaWorld said it’s sticking with its plan to double the size of its orca tanks.