The Rainbow Trout Species Identified is a California Historical Landmark, the plaque reads:
The naming of the Rainbow Trout species was based on fish taken from the San Leandro Creek drainage. In 1855, Dr. W. P. Gibbons, founder of the California Academy of Sciences, was given three specimens obtained from the creek. He described and assigned them the scientific name Salmo iridia. Rainbow Trout are now worldwide in distribution and are a highly prized game fish. California Registered Historical Landmark No. 970 Plaque placed by the State Department of Parks and Recreation in cooperation with East Bay Regional Park District, April 29, 1987.
Located in Redwood Regional Park, the plaque is 50 yards past the Redwood Gate entrance kiosk.
Initially it was thought that Gibbons had discovered a new species. It was later determined to be the same species named by Johann Julius Walbaum in 1792 based on specimens from Siberia, and the scientific name Walbaum gave it, mykiss, was given precedence over iridia. It was also found the trout in the Pacific basin were more closely related to Pacific salmon, Oncorhynchus, than to the Atlantic ones, Salmo, so in 1989 the scientific name became Oncorhynchus mykiss. But the common name, rainbow trout, lives on. 3