California Nerodia Watch

Nerodia Sipedon
Let’s hope we don’t get more Nerodia in the American River watersheds! Please report any sightings.

Nerodia Watch enlists citizen scientists to report sightings of Nerodia watersnakes in California. Nerodia threaten California’s native fish and wildlife species through predation and competition for resources. Their fast rate of population growth, ability to disperse overland to new habitat, and close proximity to special status species causes great concern for California’s native fish and wildlife species. This campaign is intended to monitor for the spread of existing populations, prevent the establishment of new populations, and facilitate rapid response management efforts to control or eradicate Nerodia watersnakes in California.

Currently, N. sipedon is established in Roseville (Placer County) and N. fasciata pictiventris is established in Folsom (Sacramento County) and Machado Lake (Los Angeles County). Areas that should be targeted for surveying include most types of permanent freshwater habitats, such as ponds, wetlands, canals, and slow-moving streams and rivers. Specific locations of interest include in and around Roseville, Folsom, the lower American River, the Sacramento River watershed west/southwest of Sacramento, Stone Lakes National Wildlife Refuge, Little Potato Slough, French Camp, the Sacramento-San Joaquin Delta, and Los Angeles County.

For more information on Nerodia watersnakes in California, visit CDFW Invasive Species Program – Species profiles, The California Nerodia website, the Stop the Spread of Non-Native Water Snakes in California Facebook group, and

In 2008, all Nerodia watersnake species were added to the California Department of Fish and Wildlife’s list of restricted live animals, making it illegal to possess, transport, or import them into the state without a restricted species permit from the Department of Fish and Wildlife.