Scientific name: Salvelinus confluentus
Introduction: Bull trouts are members of the char subgroup of the salmon family, which also includes the Dolly Varden, lake trout, and Arctic char. As such, its main feature is the dark body with light spots (unlike other salmonids that have clear bodies with dark spots). It is native from north western North America, commonly known as a voracious predator of other fish. There are three types of bull trout: lake residents, river residents and anadromous sea-run.
Distribution: It can be found in several north western states of the United States and in Canada in the states of Alberta and British Columbia. Water temperature is the main limitation for bull trout distribution, as it prefers water that reaches 10 to 12 degrees Celsius, with highs of 15 degrees during summer.
Weight and Measure: In streams it can grow to 3 pounds, while in rivers and lakes bull trouts can reach 20 pounds. Larger sizes of these are associated with the existence of kokanee salmons in the lakes (landlocked sockeye in lakes), fish that are part of their diet.
The world record was 33 pounds, a specimen caught in Lake Pend Oreille in Idaho,in 1949. Unverified bull trouts of 40 pounds have been reported in the Kootenay Lake in British Columbia, where kokanee salmon are native.
Habitat and life cycle: Bull trout reach sexual maturity between four and seven years of age and are known to live as long as 10 years. Spawning occurs during autumn, when water temperature decreases to 8 ° C. Unlike other salmonids, their eggs require long incubation periods (4 to 5 months). The "fry" stay in the spawning beds for about three weeks. It is characterized by the extremely aggressive way it feeds.
Physiognomy: Like other species of char, the fins of bull trout have white leading edges. Its head and mouth are unusually large for salmonids, giving it its name. Bull trouts color is highly variable, however, the background color of the body mainly ranges from olive green to brown above, fading to white on the belly, and in rivers its coloration is platinum gray. Its body is covered with small, pale-yellow to crimson spots. There are also some specimens that have white or orange bellies, and orange to red lower fins. Like most salmonids, mature males have more color than females as they gain size and age.
Bull trouts are often confused with Dolly Varden. Both have the potential to grow to sizes greater than 5.5 pounds, but their appearance begins to distinguish when they develop. Bull trout are larger on average, with a relatively longer and broader head and their eyes are positioned above the head.
Diet: Small bull trout diet consists on terrestrial and aquatic insects, but they shift to preying on other fish as they grow larger.