Steve

Thanks for your feedback. If the unsupplemented run's production is hovering at less than replacement level due to the crappy habitat, the priority in restoration efforts should rest on habitat improvement. If what you say is true, it sounds to me that managers have instead opted yet again for a techno-fix during the past 25 years that the tribe's "life support" hatchery program has been in place. That is more than 4 complete chinook life cycles in the intensive care unit!

To expand on that medical analogy, yes, we can keep a patient on artificial life support for 25 years as well.... a ventilator to do the breathing, a pacemaker to keep the heart pumping, pressor drugs to maintain blood pressure, and a surgical feeding tube directly into the stomach to keep the patient nourished while his mouth is stuffed with techno-tubes. But if the underlying systemic cause for the patient's cardiopulmonary failure is not addressed, it's completely futile. Better to just pull the plug than to keep investing $10,000 a day on an effort that will NEVER make the patient better! If we did that for 25 years, that's 10,000 x 365 x 25 = $ 91.25 million dollars!

As far as the genetic and reproductive fitness issues are concerned, they are easily discounted when managers observe a short-term stabilization or rebound in abundance. They see fish coming back, so it's all good. As I think about it, the only way the hatchery makes up for the natural production deficit (recruit ratio less than 1) is by churning out more spawners to make up the difference. But as you'll see, that can be an unsustainable model.

Let me illustrate with an imaginary depleted run on the River Zip which has been trashed by logging. Everyone knows the habitat is crap, but let's pretend that no efforts are made to improve habitat and that habitat-limited production in the river is fixed, neither increasing nor decreasing.

In round numbers, let's say the depleted run has a 500 fish baseline and the $hitty habitat limits productivity to a recruit ratio of 0.8 (4 returning adults for every 5 spawners). That means if we do nothing, the return on those 500 spawners would be 400 recruits. Now let's put a broodstock program in place that takes 50 pairs of fish to artifically boost production. Let's say this hatchery is so good that it's recruit ratio is 2 (two and a half times better than natural).... meaning for every spawner they mine from the wild run, they get two back!

In the first year of operation, the hatchery would take 100 fish and 400 would spawn naturally. The hatchery would bring back 200 fish and natural production would bring back 320 for a total of 520 fish... a marginal gain of 20 fish or 4%. At that fixed rate of "recovery" it would take 18 years to double the run to 1000 fish.

But wait.... you can't assume the overall production will remain constant because as more and more hatchery fish are allowed to spawn naturally, the productivity from natural spawning starts to fall off due to diminished reproductive fitness. In the steelhead studies at Hood River, reproductive fitness is reduced by 15% in the first generation alone! In other words hatchery fish that are one generation removed from their wild brethren are only 85% as productive. So in our little fairy tail, where wild production in the $hitty habitat is only 0.8, the expected "natural" production from the returning hatchery fish would be only 0.68 (0.8 x 0.85).

Now let's go back and apply that misfit decrement in production to the hatchery fish in our hypothetical example. 200 of the 520 recruits arising from the original brood year were hatchery-produced, 320 were naturally produced. If all of them were allowed to spawn, they would bring back (200 x 0.68) plus (320 x 0.8) = 512 fish. In other words, in the second generation the marginal gain in productivity will be only 12 fish or 2.4% more than the baseline population of 500.

But since our hatchery is going to operate for more than just one generation, we need to cull out another 50 pair of wild fish for broodstock. So in that next generation, total production would be as follows:

(and yes Curt and Steve, I realize that I'm simplifying here because the fish actually come back in staggered age classes which makes the real analysis much more complicated, but regardless this exercise is still instructive)

the 100 wild broodstock fish brought into the hatchery would bring back 200, the 200 hatchery fish spawning on the gravel would bring back 136, and
the remaining 220 wild natural spawners would bring back 176.

Total production from that second generation would be 512 fish... in other words the fish just replace themselves.

Run the same analysis in the third generation and you get 200 fish from hatchery production, 136 fish from hatchery spawners, and 170 fish from wild spawners.... for a total of 506 fish.... a net loss of 6 fish or 1.2%.

Run the same analysis for the fourth generation and you get 200 fish from hatchery production, 136 fish from hatchery spawners, and 165 fish from wild spawners... for a total of 501 fish, a net loss of 5 fish or 1.0%.

Run the same analysis in the fifth generation and you get 200 fish from hatchery production, 136 from hatchery spawners, and 161 fish from wild spawners.... for a total of 497 fish, a net loss of 4 fish or 0.8%.

In that fifth generation all the gains from hatchery supplementation have been erased, and even with the wild broodstock hatchery program in place, the entire population is technically no longer self-sustaining. However as you can see in this example, the marginal loss with each generation does diminish, and so by the 10th generation, the losses are down to just one fish per generation at a population of about 485 fish. From there, it's just a downhill slide, albeit at glacial speed, toward extinction where every last fish counts, even the ones that are "inconsequentially" harvested in our non-selective fisheries.

I guess that's better than a baseline 20% loss per generation. If we do nothing in this example the population shrinks down to about 50-60 fish after the 10th generation. Clearly, both strategies lead to extinction... one is just so much slower and more painful to watch. The only way out of that death spiral is an increase in natural productivity. As has been said repeatedly by Lichatowich and others, you just can't have "salmon without rivers". In the end game, it's all about productive habitat... DUH!.... now there's a revelation!

As Steve said, he'd rather see the "conservation" hatchery in place while we grapple with the habitat issues.... last ditch artificial life support for our dying patient until we are willing to address what's really killing him. But let's be honest about it... the hatchery isn't "conserving" jack$hit. It's only delaying the inevitable until genuine conservation.... namely habitat restoration in this example.... can bring some semblance of natural productivity back to the system.