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The bull trout (Salvelinus confluentus) is a char of the family Salmonidae native to northwestern North America. Historically, S. confluentus has been known as the "Dolly Varden" (S. malma), but was reclassified as a separate species in 1980. Populations of bull trout in the lower 48 states are listed as threatened under the U.S. Endangered Species Act, and bull trout overall are listed as vulnerable to extinction on the IUCN Red List of Threatened Species. The Saskatchewan-Nelson Rivers population in Alberta, Canada is listed as threatened under the Species at Risk Act. Description Like other species of char, the fins of a bull trout have white leading edges. Its head and mouth are unusually large for salmonids, giving it its name. Bull trout have been recorded measuring up to 103 cm (41 in) in length and weighing 14.5 kg (32 lb). Bull trout may be either migratory, moving throughout large river systems, lakes, and the ocean, or they may be resident, remaining in the same stream their entire lives. Migratory bull trout are typically much larger than resident bull trout, which rarely exceed 2 kg (4.4 lb). Bull trout can be differentiated from brook trout (S. fontinalis) by the absence of distinct spots on the dorsal fin, as well as yellow, orange, or salmon-colored spots on the back as opposed to red spots with blue halos on the brook trout. Bull trout lack the deeply forked tail fin of lake trout (S. namaycush, another char). Distribution and habitat S. confluentus is found in the cold, clear waters of the high mountains and coastal rivers of northwestern North America, including Yukon, Alberta, British Columbia, Washington, Oregon, Idaho, and western Montana, as well as the Jarbidge River of northern Nevada and perhaps Alaska. A population of bull trout exists east of the Continental Divide in Alberta, where it is the provincial fish. The historical range of bull trout also included northern California, but they are likely extirpated. Bull trout have exacting habitat demands, requiring water temperatures generally below 55 °F (13 °C), clean gravel beds, deep pools, complex cover such as snags and cut banks, and large systems of interconnected waterways to accommodate spawning migrations. Thus, they favor the deep pools of cold lakes and large rivers, as well as high, cold mountain headwaters. Bull trout may be anadromous in coastal rivers, and individual bull trout have been found to have migrated from one coastal river to another by the ocean. Dispersal Bull trout are known for their extensive movements within river systems. They exhibit short-distance and long-distance movements, which are crucial in maintaining healthy populations and genetic diversity. During the early life stages, bull trout are often found in small, low-gradient streams or near the shores of larger rivers and lakes. As they grow and mature, they start to disperse in search of suitable spawning grounds and feeding habitats. One of the primary reasons for bull trout dispersal is the need to find appropriate spawning areas. Bull trout rely on clean, cold water and gravels of specific sizes for successful reproduction. Once mature, they migrate upstream to spawn in the same streams where they were born. This behavior ensures that the population remains connected and allows for the exchange of genetic material. The dispersal distances can vary greatly, with some individuals traveling only a few miles while others undertake extensive migrations of over a hundred miles. Long-distance dispersal is also an essential aspect of bull trout ecology. These movements often occur during the non-spawning season when the fish search for suitable feeding grounds or escape unfavorable conditions such as high water temperatures or low oxygen levels. In some cases, bull trout have been observed moving between different river basins, crossing over mountain ranges, and even traversing large lakes. These long-distance dispersal events contribute to gene flow between isolated populations, maintaining genetic diversity and increasing the species’ resilience. Understanding bull trout dispersal patterns is crucial for effective conservation and management strategies. Conservation efforts can be focused on protecting critical habitats and maintaining connectivity between populations. Conservation biologists use various techniques to study bull trout dispersal, including radio telemetry, genetic analysis, and mark-recapture studies. By tracking the movements of individual fish and analyzing their genetic makeup, researchers can gain valuable insights into dispersal patterns, population dynamics, and potential barriers to migration. Bull trout dispersal is a complex and vital aspect of their life history. Their movements are critical to maintaining population connectivity, genetic diversity, and ecosystem health. Protecting and restoring essential habitats, ensuring the connectivity of river systems, and managing anthropogenic influences in bull trout habitats are all crucial steps in conserving this iconic species. Feeding Young bull trout feed on zooplankton and zoobenthos, especially chironomids. As they grow larger, they begin to feed heavily upon other fish. In coastal Washington, some of the southernmost populations of bull trout feed heavily on salmon eggs and fry, as well as fish. Conservation The bull trout is listed as a threatened species under the U.S. Endangered Species Act throughout its range in the contiguous United States. In 1998, the Klamath River distinct population segment (DPS) and Columbia River DPS were federally listed as threatened. This finding followed a legal challenge to the U.S. Fish & Wildlife Service's (USFWS) decision in 1994 to assign a lower priority to the species' listing. The Jarbidge River DPS was listed as endangered under an emergency rule in 1998, and was subsequently downgraded to threatened in 1999. Finally, in determining that the Coastal-Puget Sound and St. Mary-Belly River DPS were threatened, the USFWS issued a threatened listing for all bull trout in the lower 48 states in 1999. In the United States, bull trout are used as a management indicator species for several national forests, including Boise National Forest and Sawtooth National Forest (Sawtooth National Recreation Area). They can also be found in the Glacier National Park. Bull trout reproduction requires cold water and very low amounts of silt, both of which are negatively impacted by road building and logging. Additionally, its need to migrate throughout river systems may be hindered by impassible fish barriers, such as dams. Bull trout populations are also in danger from hybridization with non-native brook trout. Several of these issues were raised in a long-running lawsuit where in 2003, the Oregon Natural Desert Association and the Center for Biological Diversity sued the U.S. Forest Service claiming they violated the National Forest Management Act and Wild and Scenic Rivers Act by approv.... Discover the John R Sankovich popular books. Find the top 100 most popular John R Sankovich books.