Lake Almanor fish stocking - here's the 411

This topic was brought up by Marmite a couple weeks ago, and I've also been fielding questions from locals up here regarding rumors about the CDFW fish stocking program for Lake Almanor (i.e., rumors of no longer stocking brown trout and Chinook salmon).  I got in touch with the CDFW District Fish Biologist for Plumas and Sierra counties, and here's the scoop:

The only changes so far are going from fertile fish to sterile fish (diploids to triploids).  This is to try to prevent mixing hatchery fish genetics with wild fish genetics.  I cannot guarantee what will happen in the long run, but for the time being, there are no plans to discontinue stocking anything at Lake Almanor.  The decision to no longer plant fertile fish was made at a higher level.  Last year the Chinook allotment was not filled because triploid fish were not available.  From what I understand, that should not be a problem this year.

So the only really big change is that CDFW will no longer be stocking diploid fish.  I also heard that that will apply to the Almanor Fishing Association's net pen program (they raise and release about 50,000 rainbows into the lake every year).  However, I'm not sure if this will apply to the smaller operation going on with the Chester High School's Aquaculture program.  Over the years they've been permitted to release their fish (usually around 2,000 or 3,000), consisting of diploid rainbow or brown trout, into the lake.  There may be an exception for these fish because they are the progeny of fish captured in seasonal streams that flow into the lake.

It will be interesting to see if this affects the fishing during the respective spawning seasons for these fish.  Historically, during the spawning season the lake's largest brown trout are pretty vulnerable because you know they'll be concentrating around springs and creek mouths trying to spawn.  The lake does support significant populations of wild rainbow and brown trout that use various perennial streams for spawning.  But it looks like the days of highly vulnerable, stocked brown trout in spawning condition milling around the back of Geritol Cove (where they were stocked) may be numbered.

Thanks for the updates Chris, much appreciated.

Will they be planting triploid brown trout, or only rainbows and kings?



Poor Diroblo is gonna be sad to hear about the demise of the Geritol Cove stocker browns!      

Thanks for the updates Chris, much appreciated.

Will they be planting triploid brown trout, or only rainbows and kings?



Poor Diroblo is gonna be sad to hear about the demise of the Geritol Cove stocker browns!   

From the sounds of it, everything they are stocking will now be triploid, including browns.  I find it interesting that they are now required to stock triploid Chinook.  From what I understand, these are surplus stock from the Feather River Hatchery that are more of a 'put and take' type of fishery that cannot sustain itself without constant stocking.  What genetics are they protecting by changing the Chinook to triploids if they're remaining within the same watershed?  Seems like wasted effort converting those fish to triploids.

Haha, yeah that brown trout fishery at Geritol might slowly dry up!  Poor Diroblo!  It gets hammered pretty hard by guys in-the-know.  They'll soak roe in the back of the cove there and will annihilate the browns.  I don't fish it so it doesn't bother me that the fish may stop showing up there to spawn.  It could piss off some locals that they'll no longer be able to get their easy limits of darky brown trout.  They'll just have to figure out how to catch them beyond soaking roe at the cove.

Bigger, stronger, grow faster.....did I say bigger???
But they do not reproduce.
As long as they continue stocking that lake ...forever....should still be a fun lake to fish.
What happens when they stop stocking it???????? And some dip wipe will come along and implement that idea. Just a matter of time.

Triploids still attempt to spawn I think... Just not viable... So no change?

I did some brief lit research on triploid fish, and found some interesting (and surprising) information:

- The theory that triploid fish will grow significantly faster than diploids since the triploids can dedicate all their energy to growth instead of gamete development doesn't hold true across all fish species.  Triploid channel catfish do show significantly increased growth rates.  However, triploid rainbow trout show significantly slower growth than diploids (I read this in more than one publication).

- Many male triploid rainbow trout will develop gametes, but they are not viable.  So it sounds like the males may very well develop the physical attributes you'd normally see in a male trout that's ready to spawn (i.e., hooked jaw, dark colors, humped back, etc.).  Meanwhile, most female triploids will not develop any eggs.

- Triploid rainbow trout were found to be less aggressive than diploid trout.


So according to the research, it's looking like the triploid rainbow trout that are being stocked will grow slower (and will likely be smaller) AND will be less aggressive (and thus, tougher to catch) than the diploid fish.  Lame.

Lame indeed. 

Thanks for the update Clayman. I appreciate you taking the effort to do the research.  I will pass your information on to Kenny Wilson at Camp Wilson.

Triploid browns? 
I'm not sure what the statistics bear, but the triploid rainbows they regularly plant in socal grow very big very fast. I don't doubt there is research stating the opposite is true. But c'mon, look at those huge mutant bows! With the forage available at Almanor, we may see an infestation of 20lbers in the future.

Triploid browns? 
I'm not sure what the statistics bear, but the triploid rainbows they regularly plant in socal grow very big very fast. I don't doubt there is research stating the opposite is true. But c'mon, look at those huge mutant bows! With the forage available at Almanor, we may see an infestation of 20lbers in the future.

Believe me, I'd love to see that!

But the stuff I've been reading doesn't seem to bode well for triploid fish in Almanor.  In controlled environments (like hatcheries), studies show triploid trout to grow significantly faster than their diploid counterparts.  However, the opposite is true when the fish are placed in a more 'natural' setting like a lake or river.  Seems the triploids just have a harder time getting through winter conditions, while the diploids can cope with the harsh environment just like they always have.  Those comfy SoCal lakes probably aren't comparable to an environment that sees water temperatures dip into the mid-30s for months at a time.

I honestly don't know what's going to happen with triploids in Almanor.  I really do hope they thrive and get BIG.  But the majority of the literature I've read so far suggests the opposite, for rainbows anyway.  Haven't found much on triploid browns.  One perk the browns have over the rainbows is they tend to fare better than rainbows in super-cold environments.  So who knows, maybe those monster triploid browns we dream about will become a reality  .

It's kinda like all the kids that grew up eating mikyD's and my boy Ty who grew up fishing, hunting and dry camping. If TSHTF and they all get thrown into the wild. Who would you bet on?

Thank you for the great information on the diploid vs. triploid stockings in California. Washington state and Canada have doing the same for years.

Sounds like I need to make some more trips up there soon, just in case 
Thanks for the info. Chris

It's kinda like all the kids that grew up eating mikyD's and my boy Ty who grew up fishing, hunting and dry camping. If TSHTF and they all get thrown into the wild. Who would you bet on?

I completely agree Randall: wild stocks are always going to out-live and outperform introduced "planters" in a natural setting.  But the main objective for changing all the diploid fish to triploids is to "prevent hatchery fish genetics mixing with wild fish genetics." I could see this being a damn good reason to make the switch...if it was 50+ years ago.  Diploid stockers have been dumped into lakes like Almanor for several decades, and every year those fish have run up the local rivers and streams to spawn right alongside the wild fish.  Just what amount of genetic integrity could there be left?  Not much I bet.  Let alone any truly "native" strains of rainbow, save for the few fish that wash down from the headwaters.

I guess it's better that they're making this move later than never.  Perhaps it'll open up the doors to fish stocking across different basins, like they did with abandon back in the 70s and 80s (i.e., Eel River steelhead being thrown into the American River, etc.).

If I remember correctly I heard that Triploid male fish will still spawn but that their sperm will terminate the eggs. That is why the Alsea steelhead hatchery trys to avoid male triploid fish from getting into wild populations on their return run. If they spawn with a wild female they kill her entire clutch. This is a topic that the Research hatchery is looking into on what is better for the steelhead pop. Is it better for the hatchery mixing of genetics or the complete loss of the eggs. Ill try and find some papers on this what do you think Chris?

Wes