Twenty years ago, the number of fall chinook salmon returning to the South Fork Stillaguamish River was too low to support a hatchery program using conventional broodstocking methods.
To address this challenge, the Stillaguamish Tribe of Indians implemented a less common approach at its Brenner Creek Hatchery: raising captive broodstock to support chinook recovery while salmon co-managers work to restore habitat. While progress has been gradual, the trend is positive.
“Escapement numbers have slowly started to tick upwards since our operations began,” said William Irwin, the tribe’s hatchery manager. “The goal is to stave off extinction of Stillaguamish chinook while rebuilding habitat, which the tribe is also actively working on.”
Since the first group of captive broodstock was spawned in 2014, the hatchery has released more than 1 million offspring into the river system, supporting the incremental rebuilding of the population.
“We’re seeing encouraging signs that this strategy is working,” said Kadi Bizyayeva, Fisheries Director for the tribe. “Every year brings us closer to a self-sustaining population in the Stillaguamish River.”
For captive broodstocking, natural-origin juvenile salmon are captured from the river system and raised at the hatchery. This controlled environment enhances survival by reducing predation, maintaining water quality and providing nutrition for up to six years, until the salmon reach spawning maturity.
“It’s a very unique program,” Irwin said. “It also enhances fish culturists’ knowledge and skills.”
At any given time, the hatchery managed multiple age classes of fall chinook—from newly captured juveniles to mature adults—alongside the latest fry raised for release.
Each of the broodstock fish undergoes routine fish health monitoring and is individually tagged and DNA-sampled to ensure genetic diversity among.
The hatchery aims to release about 200,000 juvenile chinook each spring. These fish are marked with coded wire tags, enabling biologists to track their origins and migration patterns when encountered in rivers or the ocean.
“We’re constantly learning from this run thanks to coded wire tag data,” Irwin said. “We’re learning a lot about northern impacts from Canadian and Alaskan fisheries.”
In October, the tribe’s fisheries staff began spawning the latest group of adult chinook raised as captive broodstock. Their offspring began hatching in November and will be released in the spring.
Above: Scott Boyd, deputy fisheries director for the Stillaguamish Tribe, delivers fertilized chinook eggs to an incubation station in the Brenner Creek Hatchery. Story and photos by Kimberly Cauvel
