By Joseph Nasr BERLIN (Reuters) - Migrant arrivals in Germany dropped significantly last month, but the reason was rough seas, not efforts by Turkey to crack down on illegal departures to Greece, German Interior Minister Thomas de Maiziere said on Wednesday. "Our impression is that the drop (in arrivals) is predominantly linked to the weather, namely a stormy sea in the Mediterranean," de Maiziere, a member of Merkel's Christian Democratic Union (CDU), told a news conference. "We are also seeing efforts by Turkey to reduce the number of illegal migration departure from Turkey," he said.