Invasion
Invasion Description
1st record: Long Beach/CA/Colorado Lagoon, Alamitos Bay (stocked 1951, established, Selchak and Hass 1971, cited by Carlton 1979; Crane et al. 1975)
Geographic Extent
Newport Beach/CA/Newport Bay (1940, Carlton 1979); Long Beach/CA/Colorado Lagoon, Alamitos Bay (stocked 1951, established, Selchak and Hass 1971, cited by Carlton 1979; Crane et al. 1975); population decline, near extinction in 2009, Burnaford et al. 2011); Catalina Island/CA/Catalina Harbor (1959, failed, Carlton 1979); Vacation Isle, San Diego/CA/Mission Bay (1991, Hertz and Hertz 1992, 1 specimen, chipped shell, as if dropped by a bird?)
Vectors
| Level | Vector |
|---|---|
| Probable | Fisheries Intentional |
Regional Impacts
| Ecological Impact | Herbivory | |
| The large biomass of M. mercenaria in the Colorado Lagoon appears to have had a substantial impact on phytoplankton populations in 1980, although Murphy and Kremer (1985) did not measure grazing directly. However, their metabolic measurements indicate that M. mercenaria was responsible for more than 50% of the oxygen consumption and ammonium release of the benthic community (Murphy and Kremer 1985). However, those impacts are now minimal, because of the near-extinction of the population (Burnaford et al. 2011). | ||