Bull trout

Salvelinus confluentus

Nicknamed the "grizzly bear of the fish world" for its fierce disposition and reliance on pristine, unspoiled habitat, the bull trout is one of the most threatened and least-known members of the salmon family.

Bull trout behavior and facts

  • Named for its large head, the bull trout is a species of char native to Northwestern North America.
  • Bull trout are often confused with another Pacific Northwest native, the Dolly Varden, as well as the similarly-patterned brook trout, which is introduced from Eastern North America.
  • While char have light spots on dark bodies, rainbow trout and Pacific salmon have dark spots on light bodies.
  • Bull trout can vary in color, but are most often olive green with pale yellow or pinkish spots.
  • Young bull trout feed on aquatic invertebrates. Adults are highly piscivorous, meaning they feed primarily on fish.
  • In some locations, fish comprises 99% of bull trout diet.
  • Bull trout can grow to impressive sizes. The Oregon State record bull trout weighed over 23 pounds, while the largest bull trout caught in Washington weighed more than 22 pounds.
  • Bull trout are picky about their habitat, relying on the four C's to survive: Cool, Clean and Connected water and Complex habitat. They require even colder water than salmon.

Reproduction and life history

  • Unlike some members of the salmon family, bull trout can spawn more than once.
  • Some populations undergo epic migrations. In Washington's Skagit River system, individuals have been recorded swimming more than 115 miles and gaining 3,000 feet of elevation to reach their spawning areas.
  • While spawning chinook and steelhead are famous for their aerial waterfall-climbing acrobatics, bull trout can leap over and negotiate obstacles to reach spawning grounds well beyond the reach of other fish.
  • Bull trout and Dolly Varden require pristine headwaters to spawn.
  • Using her tail, the female digs a depression called a redd in gravel. She deposits eggs in the redd and the male fertilizes them. The eggs are then covered with gravel and she digs another redd upstream.
  • Spawning peaks in September and ends in November. Afterward, bull trout return to the main stems of rivers, lakes or the ocean.
  • Sexual maturity: 4 to 5 years
  • Lifespan: more than seven years

Vital statistics

  • Length: up to 37 inches
  • Weight: Up to 30 pounds

Status

Formerly one of Oregon's largest and most common freshwater fish, bull trout are now found in less than half of their former range. Human activities such as road and dam building have severely impacted trout habitat. Bull trout are listed as threatened by the U.S. Fish and Wildife Service.

Bull trout, the Oregon Zoo and you

You can see bull trout at the zoo's Eagle Canyon exhibit. These trout are on loan from the U.S. Fish and Wildlife Service to provide conservation value as a living educational display for the public.

The USFWS and other agencies and groups are working closely together to recover bull trout. Collectively, these organizations monitor the status of existing populations and are reintroducing bull trout into habitats from which they have disappeared.