How Much Water Do Fish Need?

A question fish biologists are often asked is “how much water do fish need?”

One of the major factors affecting the decline of salmonids in California is insufficient streamflow. Streamflow controls so many different aspects of the aquatic environment such as habitat-forming processes for salmonids and other native fishes. 

It also cues specific life history events such as juvenile and adult fish migrations, behavior, and, more recently, has been shown to influence the relative success of introduced or invasive species.

Changes in streamflow can also strongly affect water quality, including temperature, but also aquatic food webs. 

Science into Action

CalTrout is studying environmental flows and using innovative strategies to find out how much water fish need to ensure thriving populations and also balance the needs of people. 

California Environmental Flows Framework. The California Environmental Flows Framework (CEFF or the Framework) is a set of tools, products, and guidance, for developing ecological flow prescriptions in California.
Balancing Water for Fish and Agriculture. Hart Ranch and Cordoza Ranch flow enhancement and fish passage projects are examples CalTrout is working to improve water use efficiency and restore cold, nutrient-rich flows back to the Little Shasta, balancing the needs of livestock and wild fish.

California Environmental Flows Framework

The California Environmental Flows Framework (CEFF) seeks to determine ecological flow criteria for native fishes and other aquatic species throughout the state, which can be used to inform the development of environmental flow prescriptions.

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