Freshwater Shrimp Surveys Underway in Marin County Creeks

This adult female freshwater shrimp carrying eggs was captured, identified, measured, and released back into Olema Creek during recent shrimp surveys. The adult females captured generally measured around 42-49mm long.

NPS / Alex Iwaki

June 2019 - National Park Service biologists, in collaboration with US Fish and Wildlife, are surveying lower Lagunitas Creek tributaries for endangered California freshwater shrimp (Syncaris pacifica) for the first time in almost 15 years.

Researchers will identify any changes in the abundance and distribution of shrimp in Marin County’s shallow streams, which represent a sizable portion of the native crustacean’s limited range. Hopefully, increasing interest and awareness in the shrimp will help future conservation efforts. In particular, a species of non-native brackish shrimp (Palaeomon macrodactylus) was documented in the area, so gathering information on how both shrimp species are using the habitat may prove valuable.

Male freshwater shrimp are a bit smaller than females.

NPS / Alex Iwaki

Based on preliminary surveys, it appears that California freshwater shrimp have expanded their range throughout Olema Creek. Numbers have increased significantly relative to where they were 15 years ago.

For more information, contact Darren Fong.

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