Because fishery flows compete with irrigation needs for water, the program has been unpopular with local farmers and water districts, as well as recreation dependent on Stanislaus reservoirs. Also, despite the pulse flows, salmon and steelhead have continued to decline from the late 20th century into the 21st century (with occasional resurgences in flood years). Spring-run chinook have since gone extinct in the Stanislaus watershed, while the spring and fall steelhead runs are considered threatened. One of the biggest factors is that temperatures must be lower than for optimal spawning conditions. In years of drought, releasing too much water for steelhead in the spring leaves too cold water for salmon and steelhead in the fall. Other influences such as decrease of riparian habitat, gravel mining, and introduced predatory fish have also heavily affected native fish populations.