Cool Science

Fun Facts about Fish and the Environment of the Lower American River

Can you find all of the creatures in this “fish eye’s” view of the lower American River? Try downloading and printing this page and coloring them in. See a color version of this image.

An important part of the Water Forum’s mission is to preserve and protect the environment of the lower American River.

The Water Forum undertakes cutting-edge science to further understand how changes in temperature and flow affect the river and its ability to nurture fish. This work ranges from in-depth studies that map the river’s floor to identify best locations for habitat restoration to uncovering the exact size of gravel salmon prefer for their nests.

The Water Forum’s habitat restoration program creates protected places for Chinook and steelhead to reproduce and rear their young. In partnership with federal, state and local partners, the Water Forum has invested over $7 million to create over 30 acres of spawning beds and 1.2 miles of side channels, which are prime fish rearing zones.

Here are just a few of the cool science facts about the fish and environment of the lower American River, this region’s crown jewel. You can find resources for learning more at the links below.

Did you know…?

  • The lower American River is home to 43 fish species, including federally threatened Central Valley steelhead and struggling fall-run Chinook salmon, and is a major water supply source for nearly 2 million people.
  • The river’s temperature and flow are the most critical factors in supporting native fish in the lower American River. Cold water and proper flows are the foundation to fish survival with temperature, in particular, the greatest factor for species survival.
  • Here’s a unique fact about Chinook salmon and steelhead trout that swim in the lower American River: Most fish live in either fresh or salt water, but the Chinook salmon and Steelhead are part of a special group of fish that live in both. These types of fish are known as diadromous.
  • What’s the difference between catadromous and anadromous? Anadromous fish born in freshwater, but spend most of their life in salt water and return to freshwater to spawn. Both the Chinook salmon and steelhead trout are anadromous fish. Catadromous fish are born in salt water, but spend most of their life in freshwater and return to salt water to spawn. The North American and European eels are examples of catadromous fish.
  • A significant portion of Central Valley fall-run Chinook salmon completes their life cycle on the lower American River. On average, 17% of Chinook salmon who spawn in Central Valley streams return to the lower American River. These fish either build redds (nests) where they lay their eggs in the approximately 20-mile stretch of river below the dam or they return to Nimbus hatchery. Learn more about Fish Conditions.
  • There are three oak trees native to Sacramento, and along the banks of the lower American River you are apt to encounter valley oak trees. The valley oak tree can grow to be over 100 feet tall and some can live up to 400 years! It has thick ridged bark, matte green leaves that have a velvety feel and produces long acorns that grow to 3 inches in length.
  • The lower American River is the only nationally-designated Wild and Scenic River running through a major metropolitan area.

Learn more about the Water Forum’s science program and habitat work:

FISH Plan (Lower American River Fisheries and In-Stream Habitat Management and Restoration Plan): First completed in 2001, the updated plan outlines the most critical management and restoration actions needed to improve fisheries health and habitat for priority fish species in the lower American River, including fall-run chinook salmon and steelhead.

American River Rearing and Habitat Report: Provides a high-level overview of the lower American River to identify, develop initial concepts for, and prioritize potential rearing habitat enhancement sites.

The Water Forum’s flow standard for the lower American River, which establishes minimum river flows for the amount of water to be stored at Folsom Reservoir. The flow standard provides the best possible temperature and water flow conditions for threatened fish, as well as more water to be stored in Folsom Reservoir during wet or average years to save for drier years.