Information from the National Park Service
When the center of the industry moved to San Francisco in the 1870s, African Americans continued to form a large percentage of the crews. The whaling business was no doubt the largest employer of African Americans seamen on the West Coast until it ended shortly before World War I.
Over time, larger, steam-powered vessels took the place of obsolete sailing ships and black seamen were forced to accept inferior employment on ships as cooks and stewards. The era of significant participation by blacks in whaling ended in 1923 when the Wanderer went aground off Nantucket, MA.