Lightning Creek Bull Trout Habitat (Photo courtesy of Ed Connor)

Skagit River Watershed
Bull Trout Project

Bull trout don't recognize international boundaries. The Skagit River Watershed supports river life in the United States as well as Canada. Thankfully, work to help protect and understand the bull trout's life is being pursued collectively by partners beyond national boundaries.

The Skagit River begins in British Columbia, Canada. Its headwaters provide excellent habitat for bull trout. Up to a thousand square miles of habitat exists for bull trout above Ross Dam, three hundred of which is north of the border.

In 2001, to learn more about the status of bull trout in the Upper Skagit Watershed, scientists embarked on a five-part study:

1. Temperature monitoring:
   Scientists wish to know if water temperature is stable or changing in bull trout territory. Water temperature is a key indicator of habitat quality. If streams become too warm, bull trout populations will be unable to survive. Temperature data will help scientists know the natural range of water temperatures for the Skagit Watershed.
2. Juvenile and resident char surveys in key stream reaches:
   By monitoring fish in key sections of streams, scientists can begin to understand how populations in the Skagit fluctuate over time.
3. Lake drawdown and barrier monitoring during fall of 2001:
   During drought conditions Ross Lake's water level drops, and barriers can form in the mouths of rivers that enter the Lake. These barriers can have a devastating effect on populations of spawning bull trout. Scientists monitor areas which have the potential to stop migrating bull trout at spawning times.
4. Spawning surveys:
   In areas where bull trout are known to spawn, researchers count redds (nests) during spawning season. Over time, scientists will better understand the health of populations by knowing how many fish return to spawn.
5. Radiotelemetry study:
   Scientists implant small radio transmitters inside the flesh of a small sample of bull trout and follow their movements for three years. Radiotelemetry gives scientists a thorough understanding of the migrations of a few fish, which helps them understand the general movement for an entire population.

Scientists plan to continue their study. As is true in all statistical analysis, more data collected over more time will give scientists a finer-detailed view. As part of long-term monitoring efforts, scientists will:

1. Identify key spawning and rearing areas
   
2. Determine distribution and estimate abundance of native char within the Upper Skagit Basin Watershed
3. Establish population trends in Upper Skagit Basin Watershed
4. Develop watershed-wide management goals
5. Use native char as an indicator species of habitat conditions and trends

Bull Trout as an Indicator Species

Ecologists are the doctors for nature. They seek to identify indicators of health, just like doctors do when they take your temperature and blood pressure. Since bull trout are dependent on very precise environmental temperatures, scientists gain insight on global climate health by monitoring bull trout populations.

For example, if the overall climate of North Cascades was becoming warmer, so would the river temperatures, which could cause a decline in bull trout numbers. So in this scenario, it is possible that scientists could monitor bull trout populations to discover climate trends in the North Cascades. But what if bull trout are declining due to other factors, such as over-fishing, dams, inbreeding, or habitat destruction? Scientific finger-pointing can be risky business, because sometimes the factors are so complex that the culprit is difficult to identify. And sometimes there is more than one factor that may lead to a decline of a population.

However, it is important for scientists to seek reliable indicators of nature's
health. When nature is unhealthy—just like when you have a fever—it is time to find the cause(s) and work toward healthy solutions.

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