Daily newspapers in Winnipeg and Ottawa were closed today as Canada's two largest newspaper groups consolidated their holdings and tried to cut some of their losing operations.

Employes of the 60-year-old Winnipeg Tribune were told of their newspaper's closure by President Gordon Fisher of Southam Inc. in a gloomy ceremony that echoed what 375 employes of the century-old Ottawa Journal had heard hours before from management of Thomson Newspapers Ltd.

Fisher said fixed assets of the Tribune would be sold to Thomson's Winnipeg Free Press for $2.25 million. The Tribune lost $13 million between 1975-79. and a $3 million loss was forecast for this year.

The Journal, which went to morning publication in an attempt to find economic salvation, lost almost $7.7 million during the last four years as well as a loss of $3.4 million so far this year, Thomson announced.

Southam announced also that for $57.2 million it had purchased Thomson Newspapers' half interest in Pacific Press Ltd. and its one-third interest in Gazette-Montreal Ltd., which publishes the Montreal Gazette.

The consolidation of the holdings of the two major newspaper organizations was the latest in a series of corporate decisions that have shaken the Canadian newspaper industry in recent months.

The series of announcements meant that former competitive situations between the two newspaper groups were ended in Vancouver, Winnipeg and Ottawa. They had ended in Montreal 11 months ago when The Star collapsed, leaving the English-language market to the Gazette.

The Montreal Star folded Sept. 25, 1979, after a lengthy strike and ruinous circulation war with the Gazette. Earlier this month, Victoria's two major dailies, The Times and The Colonist, announced they would merge in September.