Filters: Tags: {"type":"Subject","name":"fishwithhabitattrouble"} (X) > Tags: {"type":"Subject","name":"pacificcoastregion"} (X) > Types: Map Service (X) > partyWithName: Daniel J Wieferich (X)
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The Delta Smelt (Crystallaria asprella) is only found in the Sacramento - San Joaquin River Delta in California and requires estuaries for juvenile and adult habitat along with the ability to migrate into tributary rivers to spawn in the spring. Declines of Delta Smelt can largely be attributed to the changes and fluctuations in flow of the estuarine ecosystem. Reduced flows resulting from water projects have resulted in saltwater intrusion into the Delta, which has reduced the amount of preferred habitat for spawning and nursery areas. When increased amounts of water are released by the water projects, larvae and adults become entrained and die, and both the fish themselves and the food they depend on are washed...
The Bull Trout (Salvelinus confluentus) is widely distributed within the region and occupies a variety of large lakes, small headwater streams and larger river systems. Of all the native salmonids in the Pacific Northwest, the Bull Trout generally has the most specific habitat requirements, which are often referred to as “the four Cs”: cold, clean, complex, and connected habitat. In November 1999, the U.S. Fish and Wildlife Service listed all Bull Trout populations within the lower 48 States of the United States as threatened pursuant to the Endangered Species Act. The U.S. Fish and Wildlife Service’s 2015 Bull Trout Recovery Plan lists historical habitat loss and fragmentation; interactions with nonnative species...
Both Green (Acipenser medirostris) and White Sturgeon (Acipenser transmontanus) are long-lived species with delayed and intermittent spawning that require large amounts of connected habitat to complete their life cycle. Both species use inshore marine and estuarine habitat along with rivers for juvenile and adult habitat and require clean substrates in rivers to successfully spawn. Hydropower dams are barriers to movements of these species in Pacific rivers and have negatively affected spawning success by creating unstable daily water flow patterns through peaking power operations as has been documented in other sturgeon species. For example, the fragmentation of the Columbia River by dams has created 17 land-locked...
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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