U.S. Fish and Wildlife Service Bull Trout Facts Bull trout, (Salvelinus confluentus) resident (stream) type
What is a bull trout? Bull trout are members of the char mainly an inland species, while subgroup of the salmon family, which Dolly Varden are more common in Klamath Basin in Oregon, the McCloud also includes the Dolly Varden, lake coastal areas. In Washington, both River in California and north to trout, and Arctic char. They can grow species are present in the Puget Sound Alberta, British Columbia, and possibly to more than 20 pounds (9 kg) in lake area. southeastern Alaska. Today bull trout environments. Bull trout that live in are found primarily in upper tributary streams rarely exceed 4 pounds (2 kg). How are char different from other streams and several lake and reservoir salmonids? systems; they have been eliminated Bull trout and Dolly Varden look very Char (genus Salvelinus) are distin- from the main stems of most large similar, and were once considered the guished from trout and salmon by the rivers. The main populations remaining same species. Both have small, pale absence of teeth in the roof of the in the lower 48 states are in Montana, yellow to crimson spots on a darker mouth, presence of light colored spots Idaho, Oregon and Washington with a background, which ranges from olive on a dark background (trout and small population in northern Nevada. green to brown above, fading to white salmon have dark spots on a lighter Bull trout are now extinct in northern on the belly. Spawning adults develop background), absence of spots on the California. varying amounts of red on the belly. dorsal fin, small scales, and differences Both species also exhibit differences in in the structure of their skeleton. Char What do bull trout eat? size, body characteristics, coloration, are distributed farther north than any Small bull trout eat terrestrial and and life history behavior across their other group of freshwater fish except aquatic insects but shift to preying on range. Alaskan blackfish, and are well other fish as they grow larger. Large adapted for life in very cold water. bull trout are primarily fish predators. Taxonomic work, published in 1978 and Bull trout evolved with whitefish, accepted by the American Fisheries What was the historic range sculpins and other trout and use all of Society in 1980, identified bull trout as of bull trout? them as food sources. distinct from the Dolly Varden. Com- Historically bull trout occurred pared to Dolly Varden, bull trout are throughout the Columbia River Basin, What is the life cycle of a bull trout? larger on average, with a relatively east to western Montana, south to the Bull trout reach sexual maturity at longer and broader head. Bull trout are Jarbidge River in northern Nevada, the between four and seven years of age and are known to live as long as 12 Migratory type, years. They spawn in the fall after spawning pair temperatures drop below 48° Fahren- heit (8°C), in streams with cold, unpol- luted water, clean gravel and cobble substrate, and gentle stream slopes. Many spawning areas are associated with cold water springs or areas where stream flow is influenced by groundwa- ter. Bull trout eggs require a long incubation period compared to other salmon and trout (4-5 months), hatching in late winter or early spring. Fry remain in the stream bed for up to
Illustrations: K. Morris/USFWS (continued from front) Present Range of Bull Trout in three weeks before emerging. Juvenile fish retain their fondness for the the Contiguous United States stream bottom and are often found at or near it. Do bull trout migrate? Some bull trout may live near areas where they were hatched. Others Q migrate from streams to lakes, S reservoirs (or, in the case of coastal populations, salt water) a few weeks after emerging from the gravel. Migratory bull trout attain a greater P size than resident stream fish. However, lakes and reservoirs are not good spawning habitat, so migratory bull trout may swim considerable distances to spawn when habitat conditions allow. For instance, bull trout in Montana’s Flathead Lake have I been known to migrate up to 155 miles (250 km) to spawn. Migration is important to maintaining healthy bull trout populations. R Why are they in trouble? Bull trout are vulnerable to many of the same threats that have reduced salmon populations in the Snake River Basin. full2rout2opultion2egmentsMap Key Due to their life history requirements, What is being done to protect bull trout? Bull Trout Population bull trout are more sensitive to States and Many of the actions intended to protect Segments increased water temperatures, poor Provinces other declining salmonids may also water quality, and low flow conditions 1 Klamath River help bull trout. Stream and habitat Bull Trout than many other salmonids. Past and 2 Columbia River protection and restoration, reduction continuing land management activities Rivers and 3 Coastal/Puget Sound of siltation from roads and other have degraded stream habitat, Lakes 4 Jarbidge River erosion sites, and modification of land 5 St. Mary/Belly River especially along larger river systems management practices to improve and stream areas located in valley water quality and temperature are all bottoms, to the point where bull trout important. Several state agencies have populations. In some areas, reducing can no longer survive or reproduce enacted regulations reducing or the potential for hybridization of bull successfully. In many watersheds, prohibiting bull trout harvest. Several trout with non-native fish species remaining bull trout are small, resident states have also drafted or have would enhance bull trout survival and fish isolated in headwater streams. adopted conservation plans to help bull recovery. trout populations recover. Brook trout, introduced throughout For more information, contact: much of the range of bull trout, easily Public Affairs Office hybridize with them, producing sterile What more can be done U.S. Fish and Wildlife Service offspring. Brook trout also reproduce to help bull trout? Besides the measures outlined above, a 911 NE 11th Avenue earlier and at a higher rate than bull strong commitment by private citizens, Portland, Oregon 97232-4191 trout, so bull trout populations are industry, state, Federal, and tribal 503/231-6121 often supplanted by these non-natives. groups to change, reduce or eliminate Hybridization with brown trout and activities that degrade streams and lake trout is a problem in some areas. rivers will be necessary to truly recover Dams and other in-stream structures many species of native fish. Much bull also affect bull trout by blocking trout habitat in mainstream rivers and migration routes, altering water streams is privately owned, making temperatures and killing fish as they May 1998 conservation activities on private lands pass through and over dams, or are a key element to restoring aquatic trapped in irrigation and other habitat and recovering native fish diversion structures.