Fish sampling has shown that non-native fish species now make up more than 95% of the fish biomass in the Delta. Unfortunately, the relative biomass of other non-native organisms is probably even higher.
Corbicula (Corbicula fluminea) is a freshwater clam that is well established in the Delta and lower tributaries. The clam is originally from Asia where it is known as the prosperity, or good luck, clam. Although it is largely ignored by most in the Delta, we occasionally run into people taking advantage of its abundance.