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Surveys Expand Known Ranges of Two Endangered Species

Small brown and tan shrimp perched on underwater vegetation.
Endangered California freshwater shrimp have a limited range that spans only three counties in the northern San Francisco Bay Area. This fall, five of them were found in Marin County's McIsaac Creek, where they had not previously been known to live!

© Tony Iwane / Photo 399649 / 7-4-2013 / iNaturalist.org / (CC BY-NC)

November 2019 - This fall, National Park Service biologists with funding from the US Fish and Wildlife Service made an exciting discovery. They found five endangered California freshwater shrimp in McIsaac Creek, where they had not previously been known to live! Their discovery came as part of an effort that began earlier this summer to check in on the status of the species in lower Lagunitas Creek and its tributaries for the first time since surveys for a freshwater shrimp habitat requirements study were completed in 2004. Adding to the excitement, biologists also noticed juvenile endangered coho salmon and threatened steelhead trout in McIsaac Creek during their shrimp surveys!

As a small Lagunitas Creek tributary, McIsaac Creek may not have been included in past surveys. But knowing the shrimp are there now will give biologists and park managers more opportunities to study and protect the species going forward. For example, they anticipate being extra careful with regard to land use in the surrounding area to ensure that factors like sedimentation from roads or grazing won’t start impacting habitat structure and water quality in the creek. Protecting California freshwater shrimp habitat in lower Lagunitas Creek and its tributaries is especially important because most of the other creeks within the shrimp’s limited range flow through private lands and face far more numerous threats. Meanwhile, much of the Lagunitas Creek watershed is within protected areas including Golden Gate National Recreation Area, Point Reyes National Seashore, and Samuel P. Taylor State Park.

Contact Michael Reichmuth for more information.

Golden Gate National Recreation Area, Point Reyes National Seashore

Last updated: May 7, 2020