A 1959 survey from the U.S. Fish and Wildlife Service reported Mattole spawning runs were 10,000 Chinook salmon and 4,000 coho salmon. Later in 1964, a survey from the California Department of Fish and Game reported Mattole spawning runs were 10,000 Chinook salmon and 4,000 coho salmon. During the 1980s, reports showed the Chinook salmon run fell to 3,000. This number dropped even lower in 1990 and 1991, when Chinook salmon run fell to 100 and coho salmon fell to approximately 100 as well. The American Fisheries Society classified the species as “high risk for extinction”.