Monthly Archives: January 2023

The Hybridization of the Kern River Rainbow

The Kern River Rainbow

This article is about the spread and hybridization of non-native trout species to the upper sections of the Kern River. Let me be clear: this increase and hybridization of nonnative species makes the fly fishing even better. With more species in the river there are more trout to catch. With more little trout being hatched, more bigger trout are eating them and getting huge. The great fly fishing in last few seasons of fly fishing on the Upper Kern certainly prove that. The fly fishing on the Upper Kern River has been nothing short of spectacular. The concern to many is that the Upper Kern River is one of the few places left in the world that only contains wild native trout…. A pureness that has not been “ruined” by the stocking of non-native fish.

Notice the white tipped fins and the faint par marks on the lateral line

The Kern River Rainbow is special.  It is classified by the U.S. Fish and Wildlife Service as a candidate species for listing under the Endangered Species Act.  The upper Kern River is also special. From the Forks of the Kern upstream to Tyndall Creek is a designated Heritage and Wild Trout Water.

At the end October ’22, on the annual “Couples Backpacking Trip to the Forks”, my wife Kelly caught and released a large rainbow on the Upper Kern River just short of Kern Flats. It was a beautifully colored fish. But, other than a glance I barely looked at it. That is typical of me. In my haste to get the hook out of its face and take the trophy shot and get the fish back into the river unharmed and healthy as quickly as possible I failed to notice something interesting. And concerning to many. I didn’t notice that it was most likely a male fish in spawn.

Well, one of the couples on this trip (Micah & Dasha) love to eat the trout when backpacking.  So, legally, they harvested two trout.  I’m not weird about that.  Just like I’m not weird about conventional tackle fishermen like some fly fishers are.  I just don’t like the taste of a wild native Kern River rainbow.  To me, they taste like bugs…. which, of course, is mostly what they eat. My wife Kelly likes to eat them to as does her buddy Mere.  So I do a recipe where I poach the hell out of them wrapped in foil over an open flame in olive oil, white wine, lemon and seasonings that does it’s best to take that gamey taste away… but, it really doesn’t.  I have documented it in my stories on this site a few times. 

Well, in the process of preparing the fish for the frying pan Micah says to me, “Do you want to eat some of the eggs?”   “Eggs?” I thought to myself.  “It’s October.  Kern River rainbows are springtime spawners.  Huh?”.  There are plenty of rainbow trout that are fall and winter spawning fish.  The Upper Owens River is a testament to that.  And those trout in the Upper Owens are all nonnative stocked fish that have turned wild.  They come out of Crowley Lake and up the river to spawn.  Most of those rainbow species in Crowley (and there are a number of rainbow trout species in that lake) come up the Owens River to spawn in the winter.

Well, I wrote up the story of that trip here.  And on the very top of that story is that now fairly infamous picture of my wife Kelly with that fish.  Here it is:

Notice the lack of spots below the lateral line and none on the face

Steve Schalla, my friend, authority of fly fishing in the sierra, and owner of – the ultimate resource for the fly fisher who wants to learn how to fish the sierra, saw that picture and said to me, paraphrasing, “Tim, look closely at that trout.  It’s a hybridized fish.  It barely has any Kern River Rainbow in it.  Notice the lack of spots below the lateral line.  Also notice the lack of spots on the face.  Also notice the sparse, large spots on that fish.  A Kern River Rainbow has small, peppery spots which are profuse over most of the body and on the fins.”

I pulled this straight from Steve’s site, and you can find it directly on the “interweb” at Steve’s site here:

Distinguishing Characteristics
The Kern River Rainbow can be distinguished by irregularly shaped spots that are both above and below the lateral line. The spots decrease as the extend towards the belly. Coloration is similar to the Coastal Rainbow trout, however the Kern River Rainbow has a distinct red stripe with faint parr marks along the lateral line. The dorsal, pelvic, and anal fins have a white tip. You will also find orange tints along the belly.

The Kern River Rainbow (Oncorhynchus mykiss gilberti) is a subspecies of the Kern River Golden Trout. The Golden Trout are thought to be derived from the rainbows that were isolated about 70,000 years ago by both glacial and tectonic activity. It is suspected that 10,000 years ago, Redband Rainbows or Coastal Rainbows migrated from the Northern Sacramento Basin to the Kern River System by way of the San Joaquin drainage into Lake Tulare. This was a period of very wet climate conditions. The Redbands hydridized with the Kern River Goldens to produce an unique subspecies, the Kern River Rainbow. This fish had a distinctive “rainbow trout” appearance with the coloration and spotting pattern but retained the “Golden Trout” aspect with the distinctive, yet fading, Parr Marks and Red Stripe along it’s lateral line.
Much of the integrity of this subspecies has been lost within the Kern River system due to stocking of hatchery-bred rainbow trout throughout the 1900’s. Only since 1990, has non-native trout stocking been discontinued. Recent genetic testing indicates that the purest strains of Kern River Rainbows occurs in the Kern River from the confluence of Durrwood Creek (5 miles below the confluence of the Little Kern River) to the headwaters in Sequoia National Park. These Kern River Rainbows are genetically distinct from the other rainbows found further downstream. Genetic sampling found that the rianbows below Johnsondale Bridge have hybridized with stocked rainbows to such an extent that they could no longer be considered “Kern River Rainbows”.
Pure strains of Kern River Rainbows are being reared at the Kern River Hatchery in Kernville. A program is in place to re-introduce these pure strains into its historical range and keep non-native trout out of the upper river.



I’m not a scientist; I’m not a fish biologist.  What am I is someone who is fascinated by the biology of the Kern River and its surrounding ecosystem.  So, I read and study and listen to experts as much as I can about it.  I am also someone that has fished the Upper Kern River for ~25 years.  And because of that I notice trends.

It appears to me that this hybridization of the pure strained Kern River rainbow with stocked fish is a trend that seems to be spreading farther and farther up river each year.

Another trend I have noticed is the lack of fight in some of the fish I catch and release.  I cannot tell you how many times I have said out loud and on this site, “Nothing Fights like a Kern River Rainbow.”  The Kern River Rainbow does numerous aerial acrobatic jumps and they just don’t give up.  But over last season I really did notice fish with the lack of vigor typical of a nonnative stocked fish.

Additionally, one of the trends I have noticed over time is the amount of brown trout in the Upper Kern River. Brown Trout are not native to the Kern River. They are not even native to the United States. When I first started fishing the Upper Kern it was unheard of to catch a brown trout in the Upper Kern. 15 years ago I’d catch maybe 1 brown out of every 250 trout I’d catch. 10 years ago that ratio was down to 100-1. I swear for the last couple seasons it’s more like 50-1. Shoot, I even caught a large brown right in front of the huck site.

How did stocked nonnative trout get in the Upper Kern River?

Before I attempt to explain this little “chestnut” let me talk about the sections of the river relevant: 

  • Section #4 is from Riverside Park in Kernville up to Hydroelectric Powerhouse #3 run by Southern California Edison (SCE)
  • Section #5 is from Powerhouse #3 to the Fairview Dam
  • Section #6 is from Fairview Dam to Brush Creek which is .6 miles short of the Johnsondale Bridge.
  • It is generally accepted that the Upper Kern section starts at the Johnsondale bridge and goes for over 60 miles to the river’s headwaters at Lake South America (which helps to drain Mount Whitney).

It’s well known and publicly published on the California Fish and Game site here that that the lower, downstream sections of the river (4&5) get stocked with nonnative trout. That huge amount of fish planting supports a number of businesses in Kernville and the surrounding areas. It written that CDFW tries to plant only triploid trout within these sections. A triploid is a fish that has been genetically engineered not to spawn. So, all the energy that is used for spawning goes into making them get big quickly. It’s great for the catch and keep traditional gear fishers and the sporting industry. But, as a fly fisherman if you have ever caught a 8 lb triploid, you know it’s like pulling dead weight. Hatchery fish, so crowded, eroding their fins on narrow cement lined pens has not been a recipe for success…. Especially in California. That is well documented. Interestingly enough, The Wyoming Game and Fish Department has the only captive California Golden Trout brood stock program in the world….Wyoming! How embarrassing for us Californians. It’s also interesting that most folks in the science and fly fishing communities of the rockies believe that there is no such thing as a pure strained Yellowstone Cutthroat anymore. It has succumbed to hybridization.

A few years back there was an attempt to rear pure strained brood stock Kern River Rainbows at the Kern River Hatchery. But, those fish succumbed to disease and had to be destroyed.  Disease is a common story for hatchery fish. 

So, with a man-made impediment in the Fairview dam preventing the hatchery stocked nonnative trout in sections 4 & 5 from moving up to the Upper Kern River.  And plenty of natural impediments in terms of waterfalls and class 5 & 6 rapids between the Johnsondale bridge and the confluence of the Little Kern River and the Main Fork (north) of the Kern River (commonly called “the forks”) in the way.  Then how the hell are nonnative, planted trout appearing 40 miles upriver?

Well, the short answer is that the experts assume nonnative trout were occasionally planted above the Fairview dam at the Johnsondale bridge at some point in the last 125 years.  But, there is no evidence nor documentation that I can find to that fact.  There, is, however plenty of documentation of nonnative trout being planted in the many tributaries of the Upper Kern River from the Western side of the Sierra.  In fact, there is documentation of once instance where a dozen or so women rode horse back to Upper Peppermint creek (~10 miles from the trailhead of the Forks of the Kern) and planted brown trout fingerlings around 100 years ago.  That would explain how brown trout are appearing and getting more prolific through time.  That is what brown trout do.  Just look at how they have taken over the Lower Owens River.  So seeing more and more brown trout in the upper Kern River is concerning to me.

“Honey, I’m going hunting. Do you mind grabbing your girlfriends and a bunch of the horses and carrying these little fish in buckets for 40 or so miles and pour them into peppermint creek so I can fish for them next summer?”

But get this: Many scientists believe hybridization could have occurred naturally: through a natural invasion of coastal rainbow trout. And consequently, hybridization could simply be a natural process. There are plenty of examples in nature of cross breeding.

In recent years, the California Dept of Fish & Wildlife (CDFW) conducted surveys in search of pure strained Kern River rainbow trout. Genetic studies found a population in a headwater lake to Big Arroyo which is on the High Sierra trail at an altitude above 10 thousand feet. Those pure strained Kern River Rainbows we the ones attempted at the Kern River Hatchery. Unfortunately, it was unsuccessful. An Upper Kern Basin Fishery Management Plan was written by CDFW to restore, protect, and enhance the native Kern River rainbow trout populations and prevent them from becoming an endangered species. The execution of that plan has yet to be realized.

Call to Action

Let’s be clear: Hybridization is not something that is fixable in a legitimate, let alone humane way.  You can only slow it down.  And one may not even want to fix it. Plenty of states including my own have done the “kill everything, then plant hatchery born pure strains.”  But, you can imagine the complications and risk for failure in that tactic.  Nature has a way.  Even if it’s not natural. 

Every year for the last 10 or so I have fished the Upper Kern at the end of the season.  I have documented it well on this site. The fishing season closes on November 15th.  But, the weather makes it miserable for the backpacker.  This trip is not for the faint of heart because even if it’s not snowing or raining, the nighttime temps can dip into the teens.  The fishing, however, is always spectacular.  Now I know one of the reasons why.  Much of the great fishing has to do with the spawn of the non-natives.  Male trout get really stupid during a spawn.

So, after that October 2022 couples trip I was motivated and inspired to pay special attention to catching nonnatives during the November end of season backpacking / fly fishing trip. By this time, that picture of Kelly and my stories and discussion had spread to CA DFG, CalTrout, Trout Unlimited and numerous people from the relevant forest districts. I had email threads going a mile long with the good folks interested in the state of hybridization.

The ask was simple.  Me and some of my expert level fly fishing buddies were to pay special attention to and document what we caught and released.  Documentation was defined as the picture of the trout, where it was caught, and the date and time it was caught.  Today’s smartphones stamp each picture with a lat/long in addition to the date/time so the “where and when” would be easy.  Our lack of photography skills would be the issue, but seemingly not too difficult to overcome.

Armed with an excel spreadsheet provided by the Forest District we would also have a column where we would estimate the mostly hybridized and/or nonnatives, barely hybridized or pure strained and document that.  Not a scientific process at all.  Just a gut feel from some fly fisherman.  But, this would be valuable research (and generally interesting) before a massive genetic testing effort occurs… which I imagine is in the works soon.  For me, the most exciting, interesting part of this trip was that we were going to fish and document above the giant waterfall that is around a mile upstream from Painters Camp.  It’s 200, maybe 300 feet tall.  Getting around it requires a death defying climb up the west side, which of course, I have been stupid enough to do.  Or following a trail that goes over 2 miles and almost a mile away from the river on the east side.  If you stare at that waterfall you would say, “There is no way in hell a trout can make it up that thing.”  But, mother nature has a way.

So what did amateur field biology project to see the effects of trout hybridization in the Upper Kern River yeild? Nothing. The snowstorms of mid November 2022 prevented us from even getting to the Forks trailhead. I was fine with driving my tundra in 4WD in 2-3 feet of snow on roads not plowed. We got within 4.5 miles of the trailhead. there were some awesome huge boulders on the road we had to navigate around. Ultimately, we were forced to stop in front of a giant tree, felled on the road by the storm. We didn’t even attempt to budge it. The tree lying on the ground was taller than me. We couldn’t push or pull it with the trucks because it landed perpendicular on the road. Darn.

You can see the felled tree in the way off in the distance.

So the mission is planned for spring / early summer.  And since it seems like we are going to have the biggest winter in California snowpack history it may be end of July before we can get in there to do the amateur field biology project to see the effects of trout hybridization in the Upper Kern River.  If you are interested in participating in the project, either as part of my group or on your own then email me from the contact page on this site.  


Sections of the Kern River, July 31, 2022 by Arnold Lynn

California Department of Fish and Wildlife: Kern River Rainbow

Steve Schalla’s Fly Fishing the Sierra

Wyoming Game and Fish

Wyoming Game and Fish Department – Wyoming Wildlife Magazine

California Fish and Game Fish Planting Schedule of the Kern River


How I Tie the Huck Hopper

I cannot tell you how many times I have been asked to make a video of how I tie the Huck Hopper.  Well, I have finally motivated so here it is.

Over the years, I have sold a gazillion huck hoppers off the site.  People adore this thing.  I adore this thing.  I have caught fish on the huck hopper all over the world.  But, many of you fly tyers want to tie it yourself.  I get it.  Fly fishing incorporates a lot of pleasures intermingled with some frustration and even pain.  And one of those pleasures is fooling a fish on a fly that you tied yourself.

I call my home water the Upper Kern River even though it is 300 miles north of where I live.  I have taught many many people how to fly fish on the Upper Kern River.  Shoot, my son Mark is a fly fishing guide in Bozeman and he cut his teeth on the Upper Kern.  My favorite stretch of the The Upper Kern is within the Golden Trout Wilderness and is accessed by the Forks of the Kern Trail; typically with a backpack.  What I call the forks is a 15 mile stretch of river above the confluence of the main fork, north, of the kern river and the little kern river.  There is not a lot of altitude at the confluence, less than 5000 feet, and for that 15 miles and beyond the river and it’s surrounding area supports a huge population of many species of grasshoppers.  Between teaching folks to fly fish losing hopper imitations to trees or simply just having the trout chomp and waterlog those flies I had a similar  problem to Charlie craven. Charlie Craven’s “Charlie Boy Hopper” was my inspiration for the Huck Hopper.  But, unlike Charlie, I was backpacking.  I didn’t have the luxury of tying more flies at night.  I would simply run out.  I needed a durable solution that was easy enough to tie that produced results. 

So, I started field testing my first prototypes on the upper kern and the results were spectacular.  There was just one problem.  I also needed a nymphing solution in a dry/dropper rig.  The upper kern has deep runs where getting the fly down produces very well.  But hanging two heavy nymphs below a fairly large, size 6 huck hopper would sink it.  At the same, I reasoned that the upper kern river should never see a bobber.  It’s too special.  The Upper Kern River within the Golden Trout Wilderness is designated as a “Wild and Scenic” river by the State of California.  It is one of the only places left in the world that supports a majority of wild natives: The Kern River Rainbow (KRR) is its own sub species of the rainbow trout.  So, I started tying huge huck hoppers in sizes 2 and 4.  I call them battleships.  And to my surprise the kern river rainbows continued to attack them.  In fact even the little KRRs would rise to those big huck hoppers, grabbing them by the legs and pulling them down to drown them.  Big flies equals big fish and I started catching some monster KRRs.  And those big huck hoppers could hold up even the heaviest of nymphs all day long.  Doubles were now not a rare thing on the Upper Kern with a big huck hopper on top.

Credits to the great Charlie Craven for the inspiration:

And thanks to Par Avion for the music!

The video includes fly tying techniques for the beginner. and details the materials I use and where i get them. but it also covers the background, history, why and how: