The Chumash and Tongva were removed from the islands in the early 19th century and taken to Spanish missions and pueblos on the adjacent mainland. For a century, the Channel Islands were used primarily for ranching and fishing activities, which had significant impacts on island ecosystems, including the local extinction of sea otters, bald eagles, and other species. Several of the islands were used by whalers in the 1930s to hunt for sperm whales. As most of the Channel Islands are managed by federal agencies or conservation groups, the restoration of the island ecosystems has made significant progress. An example of conservation progress has been the bald eagle, which was threatened due to DDT contamination, but whose populations are now recovering. With the help of scientists from the USC Wrigley Institute for Environmental Studies, the Catalina Island Fox has also recovered from a low of 100 individual foxes to over 1,500 foxes in 2018.