Nueces Bay is a northwestern extension of Corpus Christi Bay in the San Patricio and Nueces counties of Texas. The bay is fed by the Nueces River, forming a natural estuary, which renders it ecologically and economically vital to the surrounding area. It serves as a habitat for the propagation of fish and shellfish, which sustain diverse species of birds and other wildlife. The bay is threatened by pollution from the heavy industry on its southern shore, which prevents oyster farming. Petrochemical production and oil are important to the surrounding economies of the major settlements of Corpus Christi and Portland, found on the eastern shore and connected by the Nueces Bay Causeway at the bay's confluence with Corpus Christi Bay.