Some people do eat the perch and other small fish. Near Stockton, the river is nothing more than a canal, its banks cleared of natural habitat. Indistries and cities pump treated waste into the river, whcih also collects farm drainage from upstream. Downstream, the Pacific Ocean sloshes salt up the river and back again with each change of tide. Recreational fishing is slumping, industry officials say.
Fish are smaller and less abundant.
And low water flow greatly reduces the oxygen, which affects migrating salmon and other fish in the Stockton area. The river enters the south delta where water is pumped for drinking and sent to 22 million people statewide. San Joaquin water also is used for drinking farther downstream in Antioch. It meets standards, but many residents won't drink it because they fear its contaminants. These problems heat up in dry summers, when demand for water increases and there isn't enough flowing downstream of Friant Dam.