Without those guarantees, the aquarium said, it can’t support new zoning rules that would allow Chiofaro to build such a big project — because it would put the aquarium’s very existence at risk.

The aquarium is pushing for developer Don Chiofaro to cover any financial losses the nonprofit organization suffers during the billion-dollar construction project, which would be likely to last three years and wipe out hundreds of public parking spaces the aquarium says are crucial to its business.

The long-running debate over a skyscraper planned for the site of the Boston Harbor Garage increasingly boils down to one question: Can the New England Aquarium survive its construction?


Aquarium officials have been negotiating with Chiofaro but so far have no deal. On Friday, they asked state regulators who are reviewing proposed zoning for the waterfront to extend the time frame while the two sides keep talking.

“Life is simple right now. It’s binary,” said chief executive Maliz Beams. “Do we have an agreement to protect the survival of the institution? Or not? At this minute, we don’t.”

While Chiofaro’s 600-foot tower — in the works for a decade — has drawn criticism from a variety of neighbors and neighborhood groups, the aquarium over the last year or so has emerged as perhaps its most influential opponent. As a waterfront destination, it enjoys special protection under state law. It also has a well-connected Board of Trustees and with more than 1 million visitors a year a potentially powerful constituency. And the aquarium has hired public relations firms and the lobbying heavyweight ML Strategies to help press its case.

If not done carefully, Chiofaro’s project could pose an existential threat to the aquarium, said executive vice president Eric Krauss. The nonprofit ran a small surplus of $1.7 million in 2015, with $44 million in revenue, according to financial statements, and owes more in long-term debt than it holds in its endowment. If visits fall due to construction out front, or if the loss of hundreds of parking spaces keeps people away, the aquarium could quickly find itself in the red, Krauss said.


“We’re basically a break-even business now, before the risk introduced by someone else’s construction project,” Krauss said. “Most of our revenue comes from attendance. If that falls 10 percent, suddenly we’re down $3.5 million.”

So the organization is asking Chiofaro to promise to cover any lost revenue and to provide parking — during construction and permanently after the building is done. The aquarium wants this written into the zoning rules and is ready to fight the project until that happens.

While neither side would discuss details of the talks, citing a nondisclosure agreement, Chiofaro said he has offered a “gold-plated” plan to help manage construction impacts. He was confident a deal would soon be worked out.

“It’s a negotiation. It looks more intense than it really is,” Chiofaro said. “I’m very sensitive to the fact that they are a vulnerable institution. We have every interest in the world to have them survive, and thrive.”

Meanwhile, the talks between Chiofaro and the aquarium have rankled some other neighbors who’ve been watching the project closely.

In a letter to state regulators Friday, the Wharf District Council, which represents property owners along the waterfront, urged that any agreement between Chiofaro and the aquarium be made public before the zoning is approved.


“Such trilateral agreements potentially affect the whole community,” wrote the Wharf District Council’s president, Marc Margulies.

Condominium owners in the neighboring Harbor Towers high-rises, while noting “cause for optimism” over recent talks with Chiofaro and the aquarium, blasted new language that could enable Chiofaro’s tower to cover a larger footprint if he acquires the aquarium’s IMAX theater.

“Harbor Towers and the Wharf District Council considered this action to be a betrayal of their agreement and wholly unjustified,” wrote the Harbor Towers board.

State officials will now review public comments, which were due by Friday, and are expected to rule on the zoning plan in coming months.

The idea of Chiofaro buying and demolishing the IMAX theater is part of a broader plan the aquarium unveiled last year to create a so-called Blueway of public space on and around Central Wharf. But the aquarium said it has to be protected from Chiofaro’s construction before it agrees to the new park land. “We’d love to create the Blueway, and we’d love to be a part of it,” Krauss said. “But if we can’t survive, there’s not much we can talk about.”

Tim Logan can be reached at tim.logan@globe.com. Follow him on Twitter at @bytimlogan.