PANAMA CITY, Panama (AP) _ A Panamanian became the senior administrator of the Panama Canal on Monday for the first time in its 75-year history, a move taken under the 1977 treaties that gradually turn the waterway over to Panama.

Economist Fernando Manfredo, the deputy administrator of the Panama Canal Commission for 10 years, became acting administrator and moved into his new office, canal spokeswoman Willie Frye said.

The post of administrator has been held by Americans. The treaties require that it be filled by a Panamanian citizen after Jan. 1, 1990.

The former Panama Canal Zone, the strip of land that runs along the 50- mile-long ditch, came under Panamanian control in 1979. The treaties transfer the canal itself to Panama on Dec. 31, 1999.

Manfredo, 62, was named acting administrator because the United States rejected the candidate proposed by the government of deposed Gen. Manuel Noriega to head the canal administration. The Noriega regime opposed Manfredo.

The new government of President Guillermo Endara, in power for a few days, was unable to name its own candidate by Monday's deadline.

Endara said Monday he will give careful thought to the nomination, which must be approved by President Bush and the U.S. Senate.

Congress is in recess until Jan. 20, giving Endara at least three weeks to decide. He has said he will consider nominating Manfredo.

The Canal Commission, which operates the waterway, has two new acting deputy administrators, both Americans, Ms. Frye said.

Raymond Laverty, chief executive for planning, will be acting deputy administrator of operations and Joseph Ward, chief executive for administration, was named acting deputy administrator for administration.

Ms. Frye said organization of the commission, a U.S. government agency, will remain the same.

She said morale among operations people had been low because of harassment by the government under Noriega, but had soared following the invasion of Panama by U.S. troops on Dec. 20.

The backlog of ships waiting to transit the canal has been reduced to about 80. Eighty ships cleared the canal the past two days, about the normal number.