Judging by its scenic photos of bridges, ships and seals, San Francisco Bay: Portrait of an Estuary is the kind of book a Bayside resident might keep on her coffee table as a reminder of why her ludicrous rent is worth it.

But the book is more than a Bayside lovefest: It’s also a reckoning with just how polluted, dredged, diked and degraded this estuary has become since the days when sea otters and blue whales still swam inside the Golden Gate.

Writer John Hart chronicles the ongoing efforts to clean up what’s left of these waters and reveals the humble beginnings of that grand experiment. If not for three faculty wives at the University of California at Berkeley in 1960, there might be little left of the bay beyond a few foul shipping channels. These women started the “Save the Bay” movement back when cities were dredging and filling its waters to make way for houses and residential streets.

Hart introduces other unexpected bay-savers, such as the duckhunters who preserved a 140 square-mile swatch of marshlands to support their bird-shooting habit. Even the military, which gobbled up prime bay-view land for forts and bases, has proven a benefactor: Much of that land is now home to public parks.

Still, this is the only large bay in the world where you can no longer buy a single aquatic critter caught in its waters. Even the Dungeness crab, once so abundant it was thought a nuisance, has been overfished and crowded out by exotic invasive species.

Mucking around with Hart in the real San Francisco Bay uncovers many of the other equally intriguing — and often unintended — ways in which people are still reshaping it.

San Francisco Bay: Portrait of an Estuary
by John Hart, photographs by David Sanger.
194 pages, hardcover $34.95.
University of California Press, 2003.