Rev. Richard E. Mumma, Harvard's Presbyterian pastor, and Rev. Howard Fish, Congregational minister to the University, have resigned to open the way for a new Harvard-M.I.T. joint ministry likely to begin work next Fall.

Their resignations, effective at the end of the acedemic year, follow the recommendations of a committee sponsored by the Congregational, Baptist, Methodist, and Presbyterian churches to evaluate their ministries at Harvard this Fall.

The committee recommended that current full-time staff employed by these four denominations at Harvard and M.I.T. resign to allow the planners free rein to choose staff.

Although the new ministry has not yet been planned, it will cut down on what Mumma yesterday called the "theological zoo" at the two universities. Discarding the assumption that each minister works only with his own flock, the system might involve fewer staff members and would certainly be more "issue and task-oriented, not institution-oriented," Mumma said.

Mumma and Fish both praised the proposed changes yesterday.

Mumma has been a center for liberal and radical work at Harvard. His leaving "would be a tremendous blow to all sorts of activities," Noam Chomsky, professor in the department of Modern Languages and Linguistics at M.I.T., said last night.

The new ministry holds the promise that "the sort of things I've done can be done more effectively," Mumma said yesterday.

Although his ministry has been "controversial," Mumma said, he did not imply that the evaluating committee opposed his activities. Robert K. Funkhouser, chairman of the Presbyterian board which oversees Mumma's work at Harvard, agreed with several other observers that no disapproval was involved in the committee's recommendations.

The nature of the new ministry will depend on the composition of the governing committee, yet to be named. Mumma said that he is "not planning or hoping" to be asked back, and that he as well as Fish are making other plans. Funkhouser said, however, that Mumma might consider accepting a position under a sympathetic committee. And "the first people [the committee] would look at" are the people currently involved, Fish said last night.