head of the California Aqueduct in the Delta began their operation, the pattern of water flow in the Delta has been changed considerably leaving the fish confused as to where to go, resulting in many generations dying off because they have not been able to find their way upstream. In 2004, only 200,000 fish were reported to return to the Sacramento; in 2008, a disastrous low of 39,000. In 1999, five hydroelectric dams on Battle Creek, a major tributary of the Sacramento River, were removed to allow better passage of the fish. Three other dams along the creek were fitted with fish ladders. The river is considered one of the best salmon habitats in the watershed because of its relatively cold water and the availability of ideal habitat such as gravel bars. By the late 20th and early 21st centuries, the government blamed crashing fish populations on overfishing, especially off the Northern California and Oregon coast, which lie directly adjacent to the migration paths of Sacramento River salmon. This has resulted in a ban on coastal salmon fishing for several years since 2002. The Red Bluff Diversion Dam, although not a large dam and equipped with fish passage facilities, also presents a major barrier. Because of inadequate design, roughly 25–40% of the incoming fish get blocked by the dam each year. The dam has also become a "favorite spot" for predatory fish to congregate, feasting on the salmon that get trapped both above and below the dam. As of 2010, the salmon run has shown slight signs of improvement, probably because of that year's greater precipitation. In 1995, a gate on the Folsom Dam on the American River broke open, causing the river's flow to rise by some . The water traveled down the Sacramento and washed into the Pacific; the influx of fresh water was such that it confused thousands of anadromous fish to begin migrating up the river, thinking that the river had risen because of late-autumn storms. Whales Marine animals such as whales and sea lions are occasionally found far inland after navigating the river for food or refuge and then losing track of how to get back to the Pacific Ocean. In October 1985 a humpback whale affectionately named "Humphrey the humpbacked whale" by television media traveled up the Sacramento River before being rescued. Rescuers downstream broadcast sounds of humpback whales feeding to draw the whale