San Francisco Bay estuary is the largest estuary on the Pacific coast of the United States. It is located at the mouth of the Sacramento and San Joaquin Rivers. Since the late 1800's, this estuary has been significantly modified by a population explosion, hydraulic mining debris, land reclamation and reduced fresh water in-flows. The bay is impacted by municipal, industrial and agricultural activities resulting in contamination of its water, sediments and biota. There has been a marked decline in the populations of salmon, sturgeon, striped bass and Dungeness crab in the estuary.