Tokyo, May 22 (Bloomberg) -- Japan's trade surplus probably shrank in April as exports fell for the first time this year, signaling the world's second-biggest economy may be slow to emerge from 18 months of recession, economists said. The trade surplus probably narrowed to 947.5 billion yen ($7.6 billion), seasonally adjusted, from 1.1 trillion yen in March, according to the median of 12 forecasts in a Bloomberg News survey. The trade report will be released at 8:50 a.m., Japan time, tomorrow. The yen's 6.2 percent gain against the dollar this year may dent exports, and Japan's efforts to emerge from its third recession in a decade. Before the rally, the weak yen helped exporters such as Nissan Motor Co. boost earnings, limiting the economic contraction. ``It would be worrisome if this persists,'' said Taro Saito, an economist at NLI Research Institute, who expects export volumes to fall about 1.2 percent this quarter, after rising 6.4 percent in the first quarter, as U.S. economic growth slows. The rise in the yen, which reached a 5 1/2 month high of 124.07 to the dollar in New York trade and was recently at 124.24, has prompted concern among Japanese officials that the rally will stall the economic recovery. Finance Minister Masajuro Shiokawa yesterday called the rally ``abnormal,'' hinting the government may sell yen to reverse the gains. From a year earlier, the surplus probably widened to 1 trillion yen, not adjusted for seasonal changes, from 661 billion, the survey found. Exports probably rose on a year-on-year basis for the first time in 13 months. Trade figures for the first 20 days of April show exports rose 4 percent from a year ago.