Here is a creek by the bay.

In the creek there are steelhead trout, frogs, newts, and birds.

Here is a dam on the creek.

Where the creek once was, now there is water.

Here comes a truck with largemouth bass, smallmouth bass, channel catfish, crappie, bluegill, sturgeon, shad, carp, and trout.

Here come fishermen with spotted bass, and goldfish.

Now there is a lake with many species of fish.

Here come new birds like ospreys, cormorants, and bald eagles.

There go frogs and birds.

Here come bullfrogs and new birds.

Here come people with good intentions.

Now there are rules to prevent fishing for part of the year so that migratory birds can live in the lake without people around.

Now trout cannot be stocked in the lake to help the frogs.

No one is sure how many frogs or migratory birds used to live in the creek.

Now there is a mussel from Europe that might do bad things, even to the people with good intentions.

Now there is fear.

Now the people who brought the fish from other places and the people who fish for those fish are out of favor.

Today it's January 17, 2010.

There are no boats and no people at the lake.

There are many fewer trout.

No one knows how many frogs live in the lake.

No one knows how many migratory birds live at the lake whose ancestors lived the creek.

No one knows if and when the mussels will come to the lake.

No one knows what will happen if they do.

This is the story of San Pablo Dam reservoir, the best largemouth bass lake in Northern California (formerly)