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

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.