The troubled Centre for Coastal and Marine Sciences is to be disbanded by the Natural Environment Research Council.
Despite an Pounds 11 million rescue package nine months ago, a long-term decline in government contracts and other external work has made the centre financially un-viable in Nerc's opinion.
The future of its laboratories at Plymouth, Oban and Merseyside, specialising in aspects of climate change, pollution, marine eco-systems and coastline morphology, will be determined over the coming year.
Talks are being held with universities and other organisations, but redundancies among the 300 staff are inevitable. Nerc's other major marine science site, the Southampton Oceanography Centre, will not be affected.
John Lawton, Nercchief executive, admitted that attempts to forge the three sites into a single body had been unsuccessful. "The CCMS really has had a dreadful two years, and we have to do our best to make sure this time we get the right solution and these labs can look forward to some stability," he said.
Fifty-one posts have been lost and director Jacqueline McGlade has resigned this year.
The Proudman Oceanographic Laboratory at Bidston, Merseyside, looks the most secure of the three after it reached an agreement to forge stronger ties with the University of Liverpool in March. This amounted to a declaration of intent to relocate the lab to the university's campus.
Nerc is negotiating with the Scottish Association for Marine Science about the Dunstaffnage Marine Laboratory at Oban, though closer contact with the University of the Highlands and Islands is also being considered.
Securing the future of the Plymouth Marine Laboratory, the largest lab within the CCMS, presents the stiffest challenge to Nerc. Possible links with the Southampton Oceanography Centre or the University of Plymouth are being investigated.
Jim Cooper, of the Institution of Professionals, Managers and Specialists, which represents staff at the centre, said the unions would be meeting management today.