The Chinese mitten crab is native to the coastal rivers and estuaries of China's Yellow Sea. It was first observed in San Francisco Bay in 1992. The mitten crab is catadromous. Both sexes have a maximum carapace width of about 3 inches as adults.
Females carry eggs until hatching and both sexes die after reproduction.
Following hatching, larvae are planktonic for 1-2 months. The mitten crab has undergone an explosive growth in numbers the past several years with unknown impacts to the Bay-Delta ecosystem. It has been hypothesized that large populations will significantly reduce numbers of other invertebrates through predation, and their habit of burrowing into levees may cause significant structural damage. A more direct effect of the crab invasion has been experienced at the south Delta State and Federal fish collection facilities. The mitten crab invasion has negatively impacted the TFCF, causing high mortality of fish in collection and transport facilities.