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The Lahontan Cutthroat Trout (Oncorhynchus clarki henshawi) is native to the Lahontan basin of northern Nevada, northeastern California, and southeastern Oregon. Like other native trout species, the Lahontan Cutthroat Trout is found in a wide variety of cold-water habitats including large terminal alkaline lakes, alpine lakes, slow meandering rivers, montane rivers, and small headwater tributary streams. They currently occupy only about 10 percent of their historic range primarily due to habitat fragmentation from dams and water diversions, changes in water flow patterns, loss of riparian and aquatic habitat quality, severe drought conditions, and the introduction of non-native trout species. One population in Walker...
Reductions of flows resulting from drought and water withdrawals threaten the Fountain Darter (Etheostoma fonticola) in the headwater springs that feed the San Marcos and Comal Rivers, Texas. These are the only two places in the world this species is found. It uses dense aquatic plants and algae as habitat. It is severely threatened by the loss of vegetation caused by an exotic snail and afflicted by a parasitic non-native trematode whose life cycle uses the exotic snail as a host.
The Sacramento River represents by far the largest population of returning Chinook Salmon (Oncorhynchus tshawytscha). There are four distinct spawning runs of Chinook Salmon; fall, late fall, winter, and spring. Historically, maximum spawning runs in the Central Valley approached 2 million salmon including: 100,000 late-fall fish; 200,000 winter fish; 700,000 spring fish; and 900,000 early fall fish. Current spawning sizes are a fragment of historic numbers and some of the spawning runs are listed stocks under the Federal Endangered Species Act. In 2009, total Chinook Salmon spawning populations were fewer than 69,000 salmon including: 50,000 fall fish; 10,000 late-fall fish; 3,800 spring fish; and 4,700 winter...
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