Building better kokanee fishing through "captive broodstock" that may stabilize stocking numbers

Idaho Fish and Game’s hatcheries provide about 30 million fish annually for anglers, and those include about 7 million kokanee. These silvery, landlocked sockeye salmon are an anglers’ favorite because they fight hard and taste great. 

In many of Idaho’s most popular kokanee fishing waters, most of the kokanee caught by anglers were born in hatcheries, but the eggs that produced them were taken from fish living in the wild. Each year’s kokanee-egg supply is largely driven by how many adults survive to spawning age in the wild. 

But things are about to change in the kokanee world, in fact, they’re changing as you read this. Biologists are taking a different approach. Rather than crossing their fingers and hoping Mother Nature delivers enough kokanee (and eggs) for the next generation, Fish and Game biologists started raising thousands of “captive broodstock” kokanee in hatcheries to hopefully make egg production more reliable and predictable. 

“Kokanee fishing is really popular and important to a lot of anglers, so we’re doing our best to meet their expectations,” said Joe Kozfkay, Fish and Game’s state fisheries manager. “We face a lot of uncontrollable natural variables that can make that challenging, and we feel like raising broodstock will improve our response to some of that natural variability, so we’re giving it a try.”

A prize for a dime

Kokanee are not only a prized game fish, they’re also a great deal for anglers. Fish and Game stocks young kokanee when they’re about 3-inches long – commonly known as fingerlings – for about a dime each. Survival varies, but they’re still a real bargain.

Most anglers – especially kokanee anglers – know the number of fingerlings stocked each year is reliant on how many adults survive into late summer when the red wave swims upstream to spawn. Fish and Game biologists build picket weirs to corral thousands of adults, spawn them, and then take fertilized eggs to hatcheries.

Assuming the captive broodstock experiment works out, Fish and Game will have the option of adding eggs that were taken from adult kokanee raised in hatcheries. 

“This is not an either/or situation,” Fish and Game Hatchery Complex Manager Bryan Grant said. “Natural-origin (wild) kokanee and their eggs will still be used, and eggs taken from the captive broodstock will supplement them if biologists can’t get enough eggs from wild fish.”

Grant also pointed out that captive broodstock and “wild” kokanee are essentially the same fish. The current broodstock being raised to adults in the Grace Hatchery in southeast Idaho originated from the North Fork of the Payette River north of McCall. 

A quick (and important) overview of kokanee biology

While kokanee appear similar to trout, they’re still a bit different. After spending two to three years feeding, kokanee grow to catchable sizes, and like their salmon cousins, they die after spawning. 

Kokanee feed exclusively on plankton, which are small aquatic organisms barely visible to the naked eye. They spend most of their lives in schools suspended midwater within larger lakes and reservoirs, an environment often devoid of other game fish. Because of those traits, kokanee don’t directly compete with other fish species, and they can often thrive in waters with poor habitat for other game fish.

But few lakes or reservoirs have enough naturally spawning kokanee to provide sustainable fishing that meets anglers’ expectations. In many Idaho waters, kokanee caught by anglers originated in hatcheries.

Hatchery crews have the capacity to raise and release about 8-10 million fingerlings annually. But biologists have seen kokanee declines in many Idaho waters, including Deadwood Reservoir, which for years produced thousands of spawners that helped fill hatcheries with eggs. Due to a recent shortage of eggs, fingerling releases have bounced around 6.5 million in recent years. 

So we’re going to get lots more kokanee soon?

In the words of Lee Corso, not so fast, my friend. If it were that easy, it would have been done years ago. The goal for captive broodstock is to ensure there’s enough fingerlings to meet demand around the state, and in most waters, adding more wouldn’t necessarily mean more kokanee available for anglers. 

Idaho’s lakes and reservoirs can’t produce unlimited catchable kokanee, so there are tradeoffs. But the key takeaway is this: Fish and Game is trying to hedge its bets to ensure there will be a steady and reliable supply of kokanee fingerlings in most of Idaho’s waters where they’re currently stocked. 

How many survive to catchable sizes will still rely on many factors, some of which are beyond Fish and Game’s control. The cycle of good years and bad years for kokanee fishing (hopefully more good years), still depends on favorable environmental conditions that drive the local populations.

Because kokanee fingerlings take about 2 or 3 years to reach catchable size, one bad year of environmental conditions can affect three generations of stocked fish. To put it simply, kokanee typically need consecutive years of good conditions to produce good-to-excellent fishing, and the reverse is also true. A year or two of poor conditions can negatively affect kokanee fishing regardless of how many fingerlings are stocked. 

Managing kokanee, it’s all about tradeoffs

To summarize, biologists estimate how many kokanee a body of water can likely sustain. Consistently producing the same number of catchable kokanee every year is difficult because biologists don’t know how much plankton will be available from year-to-year. Kokanee are often stocked in irrigation and flood-control reservoirs, so lots of fish can be lost through dams during high spring flows or during summer irrigation drawdowns.

Fish and Game biologists have decades of experience managing local kokanee fisheries, so they have a pretty good recipe, but they don’t control all the ingredients.

To learn more indepth about kokanee management, read this article. 

Getting the ball rolling

As mentioned earlier, the captive broodstock project is already underway. Initial broodstock consists of about 10,000 kokanee annually, including roughly 5,000 females that are expected to produce 3 to 3.5 million eggs. For you kokanee fans out there, these will be “early spawners” that are typically stocked across central and southern Idaho and “late spawners” will remain mostly in north Idaho. 

The first fingerlings produced by captive broodstock are expected to be released during spring of 2026.

While this is a new project for Idaho, it’s currently working in Wyoming.

“We have a really good relationship with Wyoming Game and Fish hatchery staff, and we’ve used their knowledge and experience to develop a blueprint to start our program,” Grant said.

Idaho Fish and Game also currently raises about a million ocean-going sockeye annually. That captive broodstock and hatchery program is among the most advanced in the world, so there’s a lot of experience to draw from. 

Unique challenges with kokanee

Each species of trout or salmon raised in hatcheries has its own challenges, Grant said. While hatchery crews are confident the kokanee broodstock program will succeed, he expects there will still be a learning curve. 

“We don’t have surefire production data to tell us how a kokanee captive broodstock population will do at our hatcheries for three years before they will be ready to spawn,” Grant said. “We have a solid blueprint to follow, but it will be helpful to get a few years of spawning, feeding and stocking underway and learn more from there.”