Coyote Creek is a river emptying into San Francisco Bay. In 1979, a breakdown of a waste treatment plant caused a significant discharge of partly-treated waste into the South San Francisco Bay through Coyote Creek. The decomposition and nitrification of the sewage components depleted dissolved oxygen and caused hypoxia and anoxia. Fishermen reported absence of fish and pelagic invertebrates. Water quality improved rapidly after treatments and fish returned after the end of hypoxia. It is unclear exactly how much the sewage spill affected South San Francisco Bay fauna.