About 500 unionized staff at Toronto Zoo could soon be off the job, raising questions about whether the animal-filled attraction would remain open to the public.

Contract talks continue between CUPE Local 1600 and zoo management, but there is a possibility of a lockout or strike as early as May 11, local president Christine McKenzie told reporters Thursday at city hall.

“They want to eliminate all of our job security (contract) language which would really threaten the conservation and the education and the research work that we do . . .” she said before a meeting of the zoo board.

Contracting out staff positions to the private sector would threaten the integrity of behind-the-scenes programs including the breeding of endangered Canadian species and getting them back in the wild, McKenzie said. The union’s members include zookeepers, scientists and gardeners.

“It would open the floodgates, basically, for our zoo to be turned into a second-rate amusement park instead of the scientific institution that it is now.”

The zoo has struggled with sagging attendance in recent years, even with four-legged stars including baby pandas.

McKenzie said the new $18-million Wildlife Health Centre — a high-tech zoo hospital and laboratory with an atrium for public viewing — is set to open May 15.

Zoo board chair Councillor Paul Ainslie said he hopes the union and managers “reach a contractual middle ground that works for both sides.”

If there is a work stoppage, the board would try to keep the zoo open — but animal safety comes first, he said.

“We have a lot of animals that need taking care of,” he said. “If we ended in a lockout or strike situation, the safety and security of our animals would come first before trying to get people through the gates.”

Asked about any move to eliminate job-security provisions, Ainslie said: “For myself, as a city councillor, you’d hope to see the same job-security provisions that we have for (CUPE locals) 416 and 79 and nothing less than that,” referring to the city’s inside and outside workers.

Locals 416 and 79 in recent years ratified, after tough bargaining, contracts that weakened so-called jobs-for-life provisions and gave full-time workers bumping rights if the city opted to contract out their positions.

Under the 416 contract, for example, only workers with more than 15 years’ service by 2019 will have that protection.