Northern Ireland's only public aquarium looks set to go under with the loss of 18 jobs.
Exploris in Portaferry is owned by Ards Borough Council and was to be sold off to a private company Livingstone Leisure.
But the company has pulled out of the deal – reportedly over pensions arrangements for the 18 staff who work in the centre.
On Wednesday evening the development committee of Ards council voted in favour of closing Exploris instead of continuing to run it themselves or seeking another private buyer.
It costs £550,000 a year to run and attracts around 100,000 visitors each year.
DUP councillor Trevor Cummings, who chairs the development committee, said it was a difficult decision.
"The level of expenditure required is not sustainable in this economic climate, when we face so many financial pressures and regrettably, we feel this is the only realistic option," he said.
But other local representatives and academics are horrified by the committee's recommendation.
Dr Julia Sigwart, the director of Queen's University Belfast's marine laboratory in Portaferry, said Exploris is the most important asset the council owns.
"It is a world-class aquarium that showcases the spectacular and internationally important marine diversity of Strangford Lough," she said.
"We work together on scientific projects and Exploris staff regularly advise our scientists and students on the tricky business of keeping marine animals happy and healthy.
"Our colleagues and visiting scientists from around the world all visit the aquarium and everyone marvels at what a treasure it is."
NIPSA, the largest public sector trade union in Northern Ireland, said to close this facility would be "bordering on the criminal."
"Exploris is in essence a regional facility and it should not be left to Ards Borough Council to make a decision to close it, nor should the council be asked to shoulder the financial cost on its own," Nipsa general secretary Brian Campfield said.
"We are calling on the NI Executive to intervene with a commitment to safeguarding Exploris for both the short and the long-term."
The chairman of Portaferry Regeneration, Doug Edmondson, told the Down Recorder that permanently closing the aquarium would be devastating to the town.
"On its reported figures, Exploris has in the past brought over 100,000 visitors into the area annually," he said.
Alliance MLA Kieran McCarthy said he is "shocked and saddened" at the news.
"Exploris is the jewel in the tourism crown in Strangford. I am deeply disappointed that this devastating decision has been made," he said.
Last night a petition was set up online in support of saving the aquarium.
Ards Borough Council will make its final decision on the future of the aquarium next Wednesday.
If it votes to close Exploris, the council will begin negotiations with the 18 staff members who work at the centre.
That process is expected to take two months, following which, the aquarium will be put up for sale on the market.
It is not know what will happen to the academic centre or the seal sanctuary. A council spokeswoman confirmed that in the meantime, Exploris will remain open.
Exploris Aquarium in Portaferry has been open for more than 25 years. It includes a sanctuary for sick or orphaned seals. It also plays a role in research with links to the Queen's University marine laboratory.
The centre originally opened in 1987 as the Northern Ireland Aquarium to showcase the diverse local marine life. It was officially reopened as Exploris in 1994 by Prince Charles.