When the Exxon Valdez ran aground in Alaska's Prince William Sound, it unleashed a regional catastrophe whose effects continue to play out these two decades later. One such apparent effect was the subsequent collapse of the region's herring.
85 percent of oyster reefs have been lost globally. In many bays, once-plentiful oyster reefs are now functionally extinct. But shellfish lovers shouldn't panic -- most of the oysters they eat today are farmed.