Fenglin Bay is an ideal river for salmon spawning and breeding. If there is a hydropower dam downstream, salmon will not be able to breed here. Only when the trees on the shore of Fenglin Bay have lost their leaves, salmon will swim here. If you see many sea eagles and brown bears gathering in this river bay, you will know that the salmon is migrating. Now there is a lot of salmon swimming in Fenglin Bay. Based on the above statement, which of the following can be derived? ['There is a hydropower dam downstream of Fenglin Bay.', 'There are many sea eagles and brown bears in Fenglin Bay.', 'The leaves on the shore of Fenglin Bay are gone.', 'Sea Eagle and Brown Bear Feed on Salmon.']