In a move that has brought reactions ranging from shock to surprise, Robert Merry, longtime political reporter for The Wall Street Journal (circulation 2 million-plus), has decided to become executive editor of Roll Call, a weekly newsletter (circulation 7,000).

The move, described by Roll Call fans as a "coup," may be the first solid indication that new owner Arthur Levitt, chairman of the American Stock Exchange, plans to expand the publication into something beyond the light, mostly enjoyable reading it has been for 31 years.

Levitt, who said his hope is to make Roll Call "imperative reading" on Capitol Hill, bought the folksy tabloid last month from Sidney Yudain, who started the weekly, wrote for it, edited and often personally distributed it to congressional offices.

Merry, 40, now White House correspondent for The Journal, said yesterday that so far there has been "tremendous support" among his friends and associates for this leap to a publication that has been described as the hometown newspaper of Congress.

"When I first started probing, asking people I usually ask for advice about such things, I was surprised at how quickly they perceived the level of potential fun, the excitement level and the tremendous opportunity," he said.

Observing that "newspapers like Roll Call can come in under the radar screen of the metropolitan dailies," Merry said "there is a great deal of good will stored up over the years by Sid Yudain, and I want to build on that good will and expand on it."

The hiring of Merry was seen as a signal that Levitt planned to commit resources to the weekly, and Merry said he "did not take a pay cut" to come to the new job. "Levitt must be upping the ante," said Robert Neuman, administrative assistant for Rep. Morris Udall (D-Ariz). "Merry's a top-flight guy."

Said Levitt: "Before I selected Merry, I made sure of his commitment to Congress and his respect for the institution, and I'm convinced of that." As for his commitment to invest in the newsletter, which still gives more than half of its copies away each week, Levitt said there is already a new office, added staff and plans for added equipment.

"This is an indication of how committed I am," he said of the Merry hire.

Names of the last 16 regional semifinalists in the Journalist-in-Space Project were announced yesterday in Columbia, S.C., as selection of the first reporter who will travel in space moved into the next round.

The announcement of 16 candidates from the north central and western regions completed the selection of 40 regional semifinalists. The selection process is coordinated by the Association of Schools of Journalism and Mass Communication, based at the University of South Carolina.

The 40 regional semifinalists include 15 applicants from newspapers, 12 from television, two from radio, three from magazines, three from wire services and five free-lance journalists. Four semifinalists come from ABC News, and NBC News, The Washington Post and United Press International each placed two. The winning journalist was to have boarded a space shuttle this fall, but the launch was delayed because of the Jan. 28 explosion of the shuttle Challenger.

At a time yet to be determined, a 15-member national selection panel will interview the 40 regional nominees, review their applications and select five finalists. NASA will choose the winner and a back-up candidate.

North Central semifinalists are Theresa M. (Terry) Anzur, reporter for NBC News in Washington; Joan M. Esposito of Chicago, reporter for WLS-TV; Paul G. Hayes of Milwaukee, science reporter for the Milwaukee Journal; Hal Higdon of Michigan City, Ind., free-lance writer; Jim Klobuchar of Minnetonka, Minn., columnist for the Minneapolis Star and Tribune; Caroline T. (Terry) Marotta of Winchester, Mass., freelance journalist; Paul H. Recer of Houston, correspondent with The Associated Press; and Barbara M. Stanton of Detroit, reporter for the Detroit Free Press.

Western semifinalists include A. Blaine Baggett of Los Angeles, executive producer for KCET-TV; Timothy T. Ferris of Hollywood, Calif., freelance journalist; Michael W. Gold of San Rafael, Calif., contributing editor for Science 86 Magazine; Richard Hart of San Francisco, reporter for KPIX-TV; Thomas J. (Jay) Mathews of Pasadena, bureau chief for The Washington Post; Lee N. McEachern Jr. of Greenbrae, Calif., reporter for KGO-TV in San Francisco; Charles W. Petit of San Francisco, reporter for The San Francisco Chronicle; and Peter M. Rinearson of Seattle, reporter for The Seattle Times.