Conservation management often focuses on counteracting the adverse effects of human activities on threatened populations. However, conservation measures may unintentionally relax selection by allowing the ‘survival of the not-so-fit’, increasing the risk of fixation of maladaptive traits. Here, we report such a case in the critically-endangered Chatham Island black robin (Petroica traversi) which, in 1980, was reduced to a single breeding pair. Following this bottleneck, some females were observed to lay eggs on the rims of their nests. Rim eggs left in place always failed to hatch. To expedite population recovery, rim eggs were repositioned inside nests, yielding viable hatchlings. Repositioning resulted in rapid growth of the black robin population, but by 1989 over 50% of all females were laying rim eggs. We used an exceptional, species-wide pedigree to consider both recessive and dominant models of inheritance over all plausible founder genotype combinations at a biallelic and possibly sex-linked locus. The pattern of rim laying is best fitted as an autosomal dominant Mendelian trait. Using a phenotype permutation test we could also reject the null hypothesis of non-heritability for this trait in favour of our best-fitting model of heritability. Data collected after intervention ceased shows that the frequency of rim laying has strongly declined, and that this trait is maladaptive. This episode yields an important lesson for conservation biology: fixation of maladaptive traits could render small threatened populations completely dependent on humans for reproduction, irreversibly compromising the long term viability of populations humanity seeks to conserve
Of course, if rim-laying had been fixated, the species would still have become extinct...
With the caveat that some species don't qualify for protection. Variola major, for example, or Plasmodium malariae. I'd even go so far as supporting the complete elimination of Anopheles albimanus and several of its relatives, and I don't think I'm the only one.
Not trying to detract from your point, just... this area has a lot of weird wrinkles that are hard to navigate.
Radiolab reminded me of that last week, discussing some measures used to preserve the Galapagos:
It added an addendum, a heartbreaking story about bird preservation, and how difficult it is to preserve species that fare better without human contact in a world now utterly full of humans:
Then there's the feral rabbits, camels, horses (brumbies), pigs etc.
Extinction events for natural reasons shouldn't be as frequent. Otherwise there would be far fewer species left. Therefore any extinction process we witness, especially with a species starting out with a healthy population, probably isn't natural.
Without knowing which traits a species "needs", the best conservationists can do is to increase numbers while preserving diversity. The "50% of all females laying rim eggs" is just a reflection of the single breeding pair's genomes. If rim eggs had been discarded, only copies of the "good" genes could have been tossed along with those eggs, and "bad" genes inadvertently selected by virtue of not being linked to the rim egg gene - which was exactly how the rim egg gene itself came to be in the last breeding pair.
Increasing numbers while preserving diversity will give the bottlenecked gene pool a chance to mix into as many combinations as possible before being released back into the wild, without natural selection driving the species to extinction. It doesn't always work, but if it doesn't work the species was done for regardless of our efforts.
[NB A fisherman explained this to me in Mallaig Scotland, none of the fishing boats I've been on were so high tech!]
Easier for humans to recall, communicate, and error-check.
I've got a ton of pre-arranged neural circuitry, evolved over centuries, trained with decades of live data, all geared towards noticing typos and touch-typing words... It seems shame not to leverage it.
It's easy to hit random characters when touch typing on a full keyboard, but it's much easier to just swipe a couple words together in the url bar than it is to get the correct capitalization as well as having to hold down the key for about a second each time you need a number.
So this string is easier to pronounce, but it's actually fairly tricky to communicate and error-check.
I feel you wouldn't use it for actual locations, though, e.g. "it was too far away from me".
As another poster noted, at this stage they're not likely to live long enough to develop most diseases.
I guess this device would be relatively self-cleaning, then, also.
The Pacific species basically start to decompose as soon as they hit fresh water.
Once they've spawned, they fall apart like something out of a bad horror movie. I've seen semi-alive fish that you could stick your thumb through without any effort (usually snagged by a tourist who's proud of his accomplishment).
While doing a little googling, I found an article  claiming $7 million in fish ladder work after structural damage forced a reduction in water level. So perhaps this solution could be cost effective or quickly put in place in case damage occurs just before a run.
The number quoted as $9,000/'Snakeriver Sockeye' that made the 800 mile journey upstream to Redfish Lake, Idaho. In 1992, as they tell it, only one fish made it. But that apparently was the first year after the project began. Then again, only 243 made it 2011 . Only ~1,500 made it back to Granite lake, which is 400 miles upstream . So it's part of a larger problem in the area.
So the $40million spent equates to 222 fish per year on average.
I'm pretty sure the 'Fish Canon', however humane, can at least match the 1 fish every 36hrs rate of existing systems.
It's also worth noting the US Army Corp of Engineers ship large numbers of juvenile fish downstream on barges. Collecting them with the 'Fish Cannon' and then shipping them on barges back upstream (or furthest upstream lock) is just a budget/politics problem not one of technology.
NHAAP is the National Hydropower Asset Assessment Program, and it's put together a large chunk of the groundwork for the DOE's hydropower vision project.
"Our ancestors traveled the beige tube to new waters, while the two-legged creatures watched and guided them."
Also, the storytellers die before their audience hatches...
Look at 0:14. This thing is put a little bit after the start of the pipe, creating a draft. The fish's own body becomes the "plug" that this air pump pushes up.
Ok, I see. The "blower unit" was pretty easy to miss though, or maybe I'm just sleepy.
And I love the thinking that went into this invention. I really appreciate the novel approach although I can't help but wonder how they've dealt with the issue of friction and how that might affect the fish - I imagine that there's a fair amount of heat created over such a long run, even at the relatively low speeds described in the videos.
I think it has been designed for a very specific commercial issue (maximising the restocking of wild salmon). I'm guessing this has applications elsewhere where you want to transport live fish/tubular slimy animals.
Source: my dad has built some fish hatchery equipment including volitional entry devices.
If I interpreted it right, there would indeed be an obvious (gentle) downstream. :-)