Uvas Creek is the only stream in the Pajaro River watershed, and in Santa Clara County, whose water right specifies minimum winter and summer releases for maintaining fish resources.

[18] The year before Uvas Creek Dam was constructed in 1957, the Santa Clara Valley Water District (SCVWD) agreed with the California Department of Fish and Game (CDFG) in a Memorandum of Agreement (MOU) to maintain flows sufficient to protect steelhead trout (coastal rainbow trout) (Oncorhynchus mykiss irideus) populations below Uvas Reservoir and to collect and truck returning adults above the dam to spawn upstream, however this latter promise was not kept.

[19] A non-profit volunteer organization called CHEER (Coastal Habitat Education and Environmental Restoration) founded by Herman Garcia, transports steelhead stranded in drying pools to reaches of Uvas Creek that are perennial.

In 2008, Garcia's organization transported more than 23,000 steelhead, a dramatic number compared to the 100-200 fish reported in the entire Pajaro River system in 1991.

[17] Other native fish species in the Uvas Creek watershed include Sacramento sucker (Catostomus occidentalis), Sacramento pikeminnow (Ptychocheilus grandis), California roach (Lavinia symmetricus), Riffle sculpin (Cottus gulosus), Pacific lamprey (Lampetra tridentata), and Threespine stickleback (Gasterosteus aculeatus).