ORLANDO, Fla. — Multiple SeaWorld employees posed as animal-welfare activists so they could spy on critics, the company admitted Thursday.

The acknowledgment comes seven months after People for the Ethical Treatment of Animals accused SeaWorld of spying. The animal-welfare group, which has waged an intense campaign against SeaWorld, went public with evidence that a San Diego employee attended protests and made incendiary comments on social media while posing as an activist. The employee, who was placed on administrative leave, has returned to work at SeaWorld.

Reading from a statement while speaking with analysts, Chief Executive Officer Joel Manby said SeaWorld’s board of directors has “directed management to end the practice in which certain employees posed as animal-welfare activists. This activity was undertaken in connection with efforts to maintain the safety and security of employees, customers and animals in the face of credible threats.”

The admission comes at a difficult time for the company. SeaWorld on Thursday issued a fourth-quarter earnings report that showed improving attendance and revenue but then told analysts bad weather and a slowdown in Brazilian visitors have hurt attendance this year. Last week, Sea- World announced a management shakeup that includes the imminent departures of Chief Parks Operations Officer Dan Brown and Chief Zoological Officer Brad Andrews.

“SeaWorld’s latest report confirms not only that the company has employed more than one spy to infiltrate and agitate at PETA but also that it values its spies more highly than the executives who have had their heads chopped off in droves, as at least one of the spies is still working at the company,” PETA said in an emailed statement.

SeaWorld’s business has suffered in the wake of the 2013 “Blackfish” documentary, which suggested the stresses of captivity caused a killer whale to batter and drown trainer Dawn Brancheau in 2010.

The spying admission “adds in a minor way to their troubles,” said Kirk O. Hanson, executive director of the Markkula Center for Applied Ethics at Santa Clara University.

“Past scandals have resulted in short-term hits to the reputation and economic success of companies,” Hanson said. “I would expect the reaction to this incident to be similar. Unfortunately the incident contributes long-term to a cynicism about the ethics of business in general.”

SeaWorld’s stock was down 11 percent Thursday afternoon.