Before the 1849 California Gold Rush, American, English and Russian fur hunters were drawn to Spanish (and then Mexican) California in a California Fur Rush, to exploit its enormous fur resources. Before 1825, these Europeans were drawn to the northern and central California coast to harvest prodigious quantities of southern sea otter (Enhydra lutris nereis) and fur seals (Callorhinus ursinus), and then to the San Francisco Bay Area and Sacramento – San Joaquin River Delta to harvest beaver (Castor canadensis), river otter (Lontra canadensis), marten, fisher, mink, gray fox (Urocyon cinereoargenteus), weasel, and harbor seal. It was California's early fur trade, more than any other single factor, that opened up the West, and the San Francisco Bay Area in particular, to world trade.