U.S. Fish & Wildlife Service

Sacramento Fish & Wildlife OfficeServing the people, conserving the fish, wildlife, and plants of California

A Unit Of The Pacific Southwest Region

Kids' Species Information

California freshwater shrimp

Photo: Larry Serpa

California Freshwater Shrimp


Endangered. This means the species is in danger of dying out. We are currently doing a study about this species. We want to see whether it is still endangered. Kids have been working very hard to help it recover.

Since 1992, kids in Marin and Sonoma counties have been helping restore habitat for the species. They have led the fight to save it. They have worked on restoring streams, educating adults, raising money and even lobbying Congress. Can kids your age help save endangered species? Yes they can!

Read about how 4th graders at the Brookside School programs by kids in Marin and Sonoma counties.


Look at the picture above. If the shrimp was curled up, it would look like the prawns at your supermarket. The CA freshwater shrimp grows to about 5 centimeters (2½ inches), about the size of your little finger. There are lots of good photos on this Blucher Creek Watershed Council page.

Don Edwards S.F. Bay National Wildlife Refuge has a great article about the shrimp by Larry Serpa.

Serpa writes "Most of the shrimp are translucent, almost ghost-like, with colored flecks scattered across their bodies. This semi-transparent nature provides ideal camouflage from most native predators, such as salmonid fish.... Non-native fish such as bluegill and bass are not fooled by all this camouflage, since they carefully search vegetation for prey."


The shrimp are detritus feeders. They eat small decaying particles brought downstream to their pools. They brush up the food with tufts at the ends of their claws and lift it to their mouths. They are one of nature's garbage collectors. Think about how messy it would be if no one collected gargage from your neighborhood! That's why these shrimp are so important.


Streams in Sonoma, Marin and Napa counties. Serpa writes "The shrimp are found within stream pools, in areas away from the main current, where there are often undercut banks, exposed root systems, and vegetation hanging into the water. They need all of these habitat components for survival. The best habitats have a mixture of willow and alder trees."


Adults become sexually maturity by the end of their second summer. After that, they breed once a year in the fall. Females produce about 50 to 120 eggs. These remain attached to their mother throughout the winter.


Introduced fish. Loss of habitat and pollution from water diversion, impoundments, livestock, dairy and other farming. Housing developments. Flood control. Gravel mining. Timber harvesting. Stream barriers.


Kids have played a major role in saving this species.

Just about any place you live, you can help restore streams and ponds. Search the Internet for words like volunteer, stream, river, watershed, restoration, clean-up, and the name of your town or area.

Many of the ideas in What You Can Do to Help Wildlife and Plants (201 KB PDF) can help protect and recover streams. For example, be careful what you pour down sinks. Remember that it will end up in your community's water.


Pond Life: A Guide to Common Plants and Animals of North American Ponds and Lakes by George K. Reid. Golden Books. The book is specifically about ponds but it is a great introduction to life in freshwater in general.

Life on the edge: a guide to California's endangered natural resources edited by Carl Thelander. 1994 BioSystem Books. Pp. 408-409. This is a good article on the CA freshwater shrimp.

Words to Learn

Biologists call the CA freshwater shrimp Syncaris pacifica. Scientific names are in Latin or Greek.

Crustacean: Shrimps are crustaceans. This group includes crabs, lobsters, crayfish and vernal pool fairy shrimp.

Detritus is material from decomposing plants and animals.

Salmonid fish include salmon and trout.

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Last updated: November 29, 2017