 The new wave of immigration that was sparked by the gold rush would continue to have a disastrous impact on California's native population, which continued to precipitously decline mainly due to Eurasian diseases to which they had no natural immunity.Like when the Spanish missions in California were established the native inhabitants were often forcefully removed from their traditional tribal lands by incoming miners, ranchers, and farmers.There were a number of massacres, including the Yontoket massacre, the Bloody Island massacre at Clear Lake, and the Old Shasta Massacre, in which hundreds of indigenous people were killed.