A decade ago, the California Department of Fish and Game's Smelt Index was 430. Now, it's 50, based on the number and weight of the fish caught in a net in the San Francisco Estuary. Fish and Game's Randall Baxter says water exports and increased ammonium pollution from water treatment plants and an invasive clam are to blame.
BAXTER: " The zooplankton are the food…the invertebrate food for these fishes. So the clam eats the algae that the zooplankton would eat and makes it more difficult for the zooplankton to do well. And because the zooplankton are food for the fish, they have a harder time finding the food that they want."