Stockton Fish and Wildlife Office
Pacific Southwest Region

SJRNWR - San Joaquin River National Wildlife Refuge

The U.S. Fish and Wildlife Service Stockton Fish and Wildlife Office is conducting fish community monitoring and evaluation for the San Joaquin River National Wildlife Refuge.


1. Assess the species composition and relative abundance of fish communities within the Refuge. Identify the native and non-native species and their habitat usage.

2. Compare fish communities within the Refuge with those in reference sites on the San Joaquin River.

3. Determine predation by non-native fish on native fish, and feeding of juvenile Chinook salmon and splittail in channel and floodplain habitats.

Initial fish sampling on the refuge began May 30, 2001. With the assistance of Refuge personnel, and using a 15 meter beach seine, fish species present on the Refuge were identified.


San Joaquin National Wildlife Refuge

Photo: USFWS