Complex sentence: About 20,000 Filipino farm laborers and fishermen arrived to work in the Mexican west coast (i.e. Baja California, Sonora and Sinaloa), while some had awaited to enter the United States to reunite with family members in Filipino American communities in California and elsewhere.
Split into simpler sentences: About 20,000 Filipino farm laborers and fishermen arrived to work in the Mexican west coast. These areas included the Baja California, Sonora and Sinaloa, while some had awaited to enter the United States to reunite with family members in Filipino American communities in California, and elsewhere.