Emigration from Bremen: "Die Maus" Database online: http://www.bremer-passagierlisten.de/. Emigrants transcribed from passenger lists covering the years 1830-1939. Not every year is included. Bremen authorities destroyed many of the early passenger lists because of lack of space. They were preserved only for the three preceding years and then were destroyed. Other later lists were destroyed in World War II. Some of the lists from 1920 to 1939 were preserved from destruction in a salt mine in Bernburg an der Saale. These came into Soviet hands after the war and were taken to the archives in Moscow. Many of these records were returned to Bremen and are included in this database.
Database of Emigrants arriving in the United States from Germany, including the port of Bremen: Emigration Database. This is a joint project of the Historisches Museum Bremerhaven and Castle Castle Garden and others. It is an index that provides the name of the emigrant and the year of emigration. It currently contains emigrants from 1820 to 1897; 1904; 1907.
Other sources for emigration from Bremen can be found in the article "Bremen: Emigration, History and Genealogical Records" in The German Genealogical Digest. Vol. 15 No.3 (Fall 1999).