The first occurrence of the Australian redclaw crayfish Cherax quadricarinatus (von Martens, 1868) in the contiguous United States

The Australian redclaw crayfish, Cherax quadricarinatus, is a popular aquaculture crayfish that has been introduced around the world. Here we report the first occurrence of the species in the United States in Lake Balboa, Los Angeles, California. The impacts of this species are largely unknown, and further research is needed to determine the species’ effects on native ecosystems. Sampling is needed to evaluate the population status in Lake Balboa to determine to what extent the species has spread in the greater Los Angeles River basin.