Its populations originally decimated in San Francisco Bay during the Gold Rush and the consequent pillaging of every local source of food (more about that here), the Olympia oyster the West Coast's only native oyster species has been the subject of restoration projects over the years and can now be found growing wild in certain parts of the northern Bay. But a new study published in the journal Proceedings of the Royal Society B, suggests that major winter storms influenced by climate change, known as 'atmospheric rivers' when they form as a band along the west coast, can have a devastating effect on these oyster populations.
The LA Times picks up the story, which focuses on the impact of several such storms in 2011. One such storm caused a torrent of freshwater from the Sacramento-San Joaquin River Delta to spill into the Bay, changing the salinity of the water around the oysters small swaths of habitat, like at China Camp State Park.
Oysters close up when the water around them becomes too fresh, but after a short amount of time (eight days) they will either asphyxiate or build up too much waste in their bodies, leading to mass die-offs like those observed in the spring of 2011.
The oysters rebounded by November 2013, but they're still smaller than the population that was decimated five years ago and storms like the one we had last week, caused by an atmospheric river, could have a similar impact on the bivalves.
Olympia oysters are smaller than we expect oysters to be and are described as having a "coppery," sweet, and celery salt flavor, and as populations have rebounded in the Pacific northwest, diners have been able to try them in larger numbers. Our coast has become more accustomed to larger and different tasting species, many imported from Japan to begin growing here more than a century ago. Sunset Magazine did a piece about where to find Olympia oysters in Seattle, in case you're curious what they taste like, and once in a while you may see them (imported from the northwest) popping up on SF menus too.