Asian Clams

Asian clam (Corbicula fluminea) is a non-native freshwater bivalve that has established in Lake Tahoe. They are small, averaging less 1.5 inches, with light green or light brown shells. They prefer quiet water with low salinity and sandy substrates, but can thrive in brackish water bodies. They generally prefer to colonize near shore. They are thought to occasionally self fertilize and the young are hatched in the spring and usually attain sexual maturity by fall and may live up to seven years. Asian Clams can release approximately 350 offspring daily. Asian clams are a prolific and competitive species that can displace native species, alter the food chain and damage equipment. Monitoring of calcium concentrations in clam beds shows that the presence of Asian clams can provide a suitable environment for successful zebra and quagga mussel reproduction within Lake Tahoe.

Asian clams have been observed in Lake Tahoe at very low densities since 2002, but recently populations have been discovered in much higher (50-5,000 clams m2) densities in the southeastern portion of the lake and small populations have been discovered as deep as 80 meters offshore of Nevada Beach. During 2009, a new population was identified in Emerald Bay. Members from University of California, Davis and University of Nevada, Reno, have conducted pilot studies since the discovery of the Asian clam populations and have developed processes to control the populations. These control measures have shown promise on a relatively small scale, causing high mortalities in target clam populations. These control measures were upscaled during 2010 to target larger populations. University researchers and agency staff from the Fish and Wildlife Service, Tahoe Regional Planning Agency, Tahoe Resource Conservation District, and the Lahontan Regional Water Quality Control Board are members of the Asian Clam Working Group that prioritizes research, monitoring, and control projects of Asian clam populations in Lake Tahoe.