Stocking of Non-native Fish in Yosemite. The history of fish stocking dates back to 1877 when the first recorded fish stocking occurred in the area that became Yosemite National Park. Two years later, the first recorded fish stocking in Yosemite Valley occurred when 20,000 trout were planted into Valley streams. In the early days of fish stocking, fish were transported to water bodies in jugs and coffee cans and later by mule. That eventually gave way to aerial stocking beginning in 1952.