Habitat restoration is one of the most effective methods for restoring ecosystem services and functions and is an important and ongoing activity in several regions in coastal California. This has traditionally been accomplished by passive restoration via reconstruction of the physical habitat that sustains many foundation species including seagrasses, oysters, and marsh plants.  These foundation species provide refuge and trophic support for native invertebrates and small fishes, which in turn, supports larger species including birds and fishes.  The focus of our work is to develop more effective methods for restoring native Olympia oysters, while at the same time creating more complete food webs by including habitat for native cancrid crabs.  Increased abundances of these large predatory crabs can reduce predation of Olympia oysters by snails known as oyster drills (whelks). The crabs themselves are not significant predators of oysters. In most of the unstructured mud flats of California estuaries, crabs are limited by the availability of refuge from their predators.  Our project involves creating crab habitat associated with oyster restoration plots that will increase the numbers of cancrid crabs to reduce whelk populations with cascading increases in native oyster populations.

Non-native whelk preying on Olympia oysters