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Rainbow Trout of Katmai

Chasing the egg hatch in the world's most productive watershed.

Rainbow Trout of Katmai

Fly fishers, brown bears, and rainbow trout all make annual migrations to the headwater streams of Katmai National Park. (Grace Smith photo)

Because we often observe them feeding by sight, and our imitations smell nothing like natural food, rainbow trout have trained fly fishers to overlook the fact that they have an almost supernatural sense of smell. Unlike our nostrils, the nares of a trout are not connected to its respiratory system. Together with the olfactory sacs, they are a dedicated sensory system that allows trout to detect odors in concentrations of just a few parts per million.

Smell is just one of the many driving factors behind the spectacular rainbow trout migrations that occur throughout the Bristol Bay watershed of Southwest Alaska. When the first sockeye salmon egg drops high on Funnel Creek, the trout downstream in the Moraine River and farther down in 46,000-acre Kukaklek Lake can smell it, home in on the source, and find it.

Their quest for salmon eggs is also driven by seasonal changes, by inherited genetic traits, and importantly by learned behaviors. In their first year of life, the rainbow trout in these watersheds thrive on salmon eggs and later, salmon flesh, to build energy reserves for the coming winter. When the salmon nutrients are gone, the rainbows drop downstream into the many lakes that are characteristic of the region, but they will remember and return.

The sockeye salmon ecosystem of the Bristol Bay watershed is the world's largest, with Iliamna, Kukaklek, Nonvianuk, Naknek, and many other lakes and tributaries providing the foundational habitat for 30 million sockeyes to return from the sea every year, along with millions of other Pacific salmon including Chinooks, Coho, chum, and pink salmon. That's why fly fishers care so much about the Pebble Mine issue. If the Bay itself is poisoned by the mine, the salmon stocks will tumble and the entire house of cards comes down.

Even the most sheltered suburbanites are aware of the Alaska salmon migration, the brown bears that feed on them, the critical role they play in the region's economy, and of their cultural importance to the native communities that have depended on salmon for thousands of years. But the rainbow trout seem to be our little secret. They aren't intentionally harvested by tribal or commercial nets, bears don't bother with them, you don't see "Alaska trout" in grocery stores, and because they don't turn the river red, they don't serve as fodder for documentary television. But to fly fishers, they are the most valued fish that swim in Alaska.

Katmai Headwater Fish

The first sockeye salmon to enter fresh water are genetically and organically engineered to travel hundreds of miles upriver into the headwaters of each river/lake system. This is ground zero for sockeye salmon, it's the fertile gravel where the eggs are laid in the fall, and the alevin hatch in the spring. By scent and by virtue of their own genetics and habitual feeding, the rainbow trout are also drawn into these small, clear streams for a "hatch" of salmon eggs, and fly fishers gather for the same reasons they chase Green Drakes on Penns Creek, or Salmonflies on the Big Hole. It's a singular feeding opportunity for native trout that is particularly suited for fly-rod tackle and tactics, and when you hit it just right, you'll see the best of what a river has to offer.

On my most recent visit to these headwater streams–a two-week trip to first Big Ku and then Royal Wolf lodges in Katmai National Park–I had the opportunity to see firsthand the ebb and flow of the rainbow trout migration. Unlike salmon movements, which are one way up a single river to a specific spawning site, the trout–using their keen sense of smell and perhaps by visually and mentally assessing the feeding situation–quickly move up and down multiple rivers within a watershed. In that way, it's trickier than hitting the Salmonfly hatch because regardless of what happens with the insects on the Big Hole, the trout are there and presumably feeding on something. It's not that way with Alaska rainbows.

Rainbow Trout of Katmai
Egg-fed Alaska rainbows are binge feeders with enormous girths you can't fully comprehend from two-dimensional photos. They are heavy and powerful; expect them to weigh 50 percent more than trout fed on aquatic insects. (Ross Purnell photo)

One day a headwater stream will be rolling with salmon eggs and the rainbows are gorging, and just a few days later the salmon finish spawning and the trout disappear–presumably drawn to other egg-laying events in other streams. Hitting these events at their peak is no easy task, as environmental factors affect the egg drop as much as they do a mayfly or stonefly hatch, and ocean conditions and commercial harvest cause huge fluctuations in the salmon spawn from year to year. Sometimes the egg drop is a week early, sometimes it's a week late. This is the primary reason you don't want to get locked into a specific river at a specific time of year.

Case in point, on the lower American River in early September 2014, Royal Wolf guide Todd Emerson watched the trout fishing go from spectacular on a Sunday to dismal on a Tuesday. And it wasn't just a downturn in the catch rates; Emerson could see that the big trout just left for greener pastures. So while some unfortunate souls were pumping up their rafts for a six-day camp-and-float on a river the rainbows had already deserted for the year, we flew to the Moraine, where the rainbows had just mysteriously shown up. Flexibility is key in a wilderness region as vast as Katmai.

Matching the Hatch in Alaska

When the trout are on eggs, the fishing can be ridiculously easy, particularly if you've reached an area that doesn't get much fishing pressure, or a new crop of fish has just moved up from the lake into an egg drop that is just getting underway. In those instances, any bright pink/orange spot of color brings savage hookups.

In most instances however, matching the egg hatch is as detailed and technical as a Trico spinner fall on the Missouri because the trout get caught, released, and trained, while the food is both uniform and plentiful–it's a perfect storm of selectivity.

In any match-the-hatch situation, size, shape, and color (in that order) are the most important variables. In Alaska, plastic beads perfectly imitate the round shape of every salmon egg, so size and color become the only variables. Is it still a fly if there are no fur or feathers on the hook? That's up to every fly fisher to define for themselves, but I know it's just as "natural" as a Chubby Chernobyl, and more in line with the traditions of matching natural trout foods than any trout nymph made with a gold bead. The good news is that for anglers with a fly-tying ethos, you can hand-paint each bead with fingernail polish to create unique mottling patterns the trout will appreciate.


Chinook salmon eggs are from 8 mm to 12 mm in diameter due to the variability in the size of the salmon. The other salmon species are more standardized: Coho salmon eggs are 7 mm, pink salmon 6.8 mm, chum salmon 7 to 9 mm, and sockeye salmon eggs 6 mm.

Egg color is incredibly important, as the trout are acutely aware of poor imitations in the clear water, and will move 3 feet to the side just to avoid a bead that is the wrong shade of apricot. Like a mayfly hatch, the egg drop moves through different phases. One group of spawning sockeyes may be dropping fresh, brilliantly clear orange eggs, while just upstream another group may just be digging new redds, and in the process stirring up old, fertilized, or dead eggs, which are different colors from mottled peach to dirty white or amber.

Experienced guides can look at a group of salmon and assess what's actually going on, but often the trout play by their own rules and in some instances prefer a different color than what you might expect. Your guide will likely carry enough beads to entertain a kindergarten class for hours, but it's always fun to come prepared with your own. sells more than 100 different colors of 6 mm beads, but your best bet is probably the "Alaska Selection" of 12 different colors (360 beads total) for $40.

Rigging. The old-school pegged-bead rig used a figure-eight stopper knot in the monofilament less than 2 inches above a short-shank hook, and a flat toothpick to jam the bead in place. The trout eats the bead, you set the hook, pulling the point into the outside of the fish's mouth. (It's better for the fish than most fly patterns where the hook is inside the mouth and can cause more significant injury or bleeding. I use size 10 and 12 Tiemco 2499 barbless Super Point hooks.)

Rainbow Trout of Katmai
Richard Clark casts to Lake Iliamna rainbows on the Gibraltar River under the guidance of Royal Wolf guide Kris Kennedy.

You can also skip the peg altogether and knot the monofilament around the bead using an improved clinch knot. To hide the knot, just slide it around so it's inside the bead. The slickest and most durable method is to use clear, tapered silicone pegs from to position the bead on the line, and then neatly clip the ends of the peg flush with the bead. The bead won't slip, and the clear peg won't discolor your natural-looking egg, or ruin the perfectly round silhouette.

Apart from the terminal tackle, the leader setup is pretty standard, with 3X nylon tippet standard in most situations. Be careful in experimenting with 4X tippet, as you may get more strikes, but Alaska rainbow trout fat with a summer of feeding are uncommonly strong and heavy. In the small headwater streams of Katmai National Park in August–prime time for sight fishing with 5- and 6-weight rods–expect plenty of 18- to 24-inch rainbows that are 50 percent heavier than any insect-eating rainbows you've encountered in the Lower 48.

Lodges. I've fished the Bristol Bay area regularly since 1996, and have encountered myself and heard of some shady operators who promote the snagging of salmon, abuse and exploit their own employees, and in rare cases, even take deposits to lodges they no longer own. The remote wilderness of Alaska is home to some "characters," so I advise everyone to work through a dependable booking agent who has visited and verified the outfitters they work with. Mike Mercer at The Fly Shop at Redding, California ( has in the past 33 years visited more fly-fishing venues in Alaska than anyone else in the industry. Other reputable agents include Jim Klug at Yellow Dog Fly Fishing and Ken Morrish at Fly Water Travel.

Mercer arranged my trip to Royal Wolf Lodge to coincide with the peak of the sockeye spawn in Katmai rivers. The lodge is located on the outflow of Nonvianuk Lake, and we flew each day in float planes to a different river in or near the park. Chris and Linda Branham built the lodge piecemeal starting in 1993 and today have one of the most comfortable and spacious wilderness lodges anywhere in Alaska, with a sterling reputation for outstanding fishing and hospitality every year. It's difficult for newcomers to get in, as repeat customers take most of the space and get priority for their favored weeks.

Chris Branham has 45 years experience as an Alaska bush pilot and personally flies one of the lodge's three planes each day. There's no one I'd rather fly with, as his safety record and experience are unparalleled.

Beyond the lodge facility, the local waters which are among the most productive wild trout rivers in the world, and the experience of staying and fishing inside one of the country's best true wilderness parks, guests will most of all appreciate the expertise and experience of Royal Wolf's unparalleled full-time guide staff.

It's common elsewhere in Alaska to end up with a twenty-something guide from the Rockies who is experiencing Alaska for the first time himself. That's not how it is at Royal Wolf Lodge. Chris Branham has put together a "dream team" of experienced professional guides, many of them with decades of experience in Alaska, all of them also highly coveted guides on other waters in the Alaska off season, from Mexico to Patagonia and the spring creeks of California. Dave Goodhart, Todd Emerson, Kris Kennedy, Ryan Davey, and Scott O'Donnell can teach you how to Spey cast on the Kvichak, spot rainbows as well as any Kiwi guide, navigate rapids, evade and deter grizzly bears, and make the most of your time on the best rivers Alaska has to offer. Enjoy your trip!

Ross Purnell is the editor of Fly Fisherman.

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