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
This sounds like a success story to me, not a failure, despite the unintended consequences. I feel like the stories not finished though. Was the population able to survive without humans going forward? Or has it entirely died? Or something in between?
I think the lesson should be: If a species is hovering over the brink of extinction, it's a better idea to do whatever it takes and only worry about the consequences later...
Of course, if rim-laying had been fixated, the species would still have become extinct...
> If a species is hovering over the brink of extinction, it's a better idea to do whatever it takes...
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.
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:
http://www.radiolab.org/story/birds/
Cane toads were introduced to Australia [1] with devastating consequences to the local fauna. I suspect that's one of the species it'd be most happy to be rid of.
Then there's the feral rabbits, camels, horses (brumbies), pigs etc.
Or perhaps to dig deeper as to WHY they are on the brink of extinction. If they develop a trait that causes them to lay their eggs on the rim (which can be directly linked to the species decline), isn't that just Darwin at work? Who are we to step in an say "yep, they're idiots for doing it, but we should still save them."
Charles Darwin was a scientist, not a super-natural deity responsible for evolution. He can't be "at work".
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.
That kind of trait doesn't just come out of the blue - there always is some form of selection pressure involved. Most likely caused by us in some way. That's why we need to step in. But yes, ideally at the point that causes this selection pressure to exist in the first place.
Natural selection isn't some benevolent deity. Its MO is to drive species to extinction, it's just that when some individuals find a way around it we call that evolution.
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.
Transferring live fish by pipeline has been used in the fishing industry for a long time - large trawlers will store fish in salt water in tanks and when they get into port they are transferred by pipeline directly from the trawler to the fish processing plant so they are still alive when they hit the table where they are "processed".
[NB A fisherman explained this to me in Mallaig Scotland, none of the fishing boats I've been on were so high tech!]
I wonder if the tech is any different. If the fish are going to be slaughtered shortly, then it wouldn't matter (ethics aside) if they're a little hurt in the process, provided the meat isn't damaged, whereas here it is quite important that the fish remain unharmed.
For the bears this company will supply intrastomach vacuum feeder, once supplied from the salmon cannon, it will fire every fourth salmon directly into bear's guts.
Gfycat seems to use a randomized adjective-adjective-animal_name for their URL structure. Certainly more memorable than the imgur six-character alphaneumeric string.
An utter bitch to type compared to a short string of garbage, though, and typing a URL manually (friend gives you a URL over the phone or in person) is the only case I can think of where the URL itself matters.
Well, I guess we'll just have to agree to disagree. I'd rather type out "Ethiopian" than waste time finding out that someone said "bee" instead of "dee" or accidentally putting "e9800998" instead of "e9800098".
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.
I find it the opposite to be honest, but probably only because I'm using swype on mobile.
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.
There appear to be some snags, though -- "Faraway" is lacking capitalization for the "away" bit, and, even more confusingly, "wolf" isn't capitalized either. Word boundaries aren't always obvious, but I feel certain that the "wolf" of "Ethiopian wolf" is an independent word.
So this string is easier to pronounce, but it's actually fairly tricky to communicate and error-check.
You'll note that I characterized "Ethiopianwolf" as being even more confusing than "Faraway", since "wolf" is definitely a separate word and it isn't clear whether "away" is or not. That unclarity still makes it difficult to communicate the capitalization in the case where capitalization matters.
Are they actually case-sensitive, though? Randomly capitalizing words seems to have no effect to me (unless iOS is sneakily autocorrecting it), so it's something of a moot point.
Capitalizing random letters in the URL didn't have any effect for me either. So I'm a little confused as to why they show the capitalization they do, but I withdraw the idea that there's a usability problem.
I wonder how this affects the fish's slime coating, which is important to preserve. It seems like this would be rubbed off on the material as the fish is propelled along the tube, no?
I'd be more worried about disease propagation. Would need to be self-cleaning, methinks .. super-clean the pipe in between fishy-pilot takeoff with a super-steaming? Hmm .. Combine the two, and we've got lunch. :)
It seems unlikely that they're going to be exposed to anything in the tube that they're not already exposed to when they congregate together at the bottom of a dam (or a natural waterfall). They can get pretty packed..
As another poster noted, at this stage they're not likely to live long enough to develop most diseases.
They can create more just as your body would create scar tissue if I scraped some of your skin off. Meanwhile, the exposed area is far more likely to become infected as your skin no longer protects it. Not a perfect analogy but it illustrates my point well enough.
Since this is to help them on their final stage of their migration to the spawning grounds (after spawning they die), I don't think infection is a big issue.
All Pacific salmon (which is what these are) die after spawning. A few Atlantic salmon (about 10%, ATW) will survive to make another trip.
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).
I recently watched DamNation [1] and was quite surprised at the shear number of dams located in the United States. The film claims that most have outlived their purpose. I can't recall the exact cost stated per fish to divert them around dams or raise them in a hatchery, but it was fairly high. The film's production quality was quite high and was fairly eye opening.
While doing a little googling, I found an article [2] 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.
Per this comment, I checked out 'DamNation'. It was fascinating, thanks for the recommendation.
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 [1]. Only ~1,500 made it back to Granite lake, which is 400 miles upstream [2]. 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.
Oh, I'm glad you said that. I didn't watch the second video because I didn't expect it to be any better than the first, but it turns out it's way more informative.
If you're interested in the current state of the US hydropower generation, potential resource out there, and really most everything around hydropower in the USA, check out the NHAAP website.
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.
This would be crazy if fish start to understand the cannon. Use it on their own and then continue on to find their destination (rather than be totally lost and confused)
Similar to how the salmon "learned" to swim back to where they were born, the increased survival frequency of salmon who can efficiently negotiate such a cannon would be expected to change the population.
I've just finished listening to a radio interview where the guest asserted that technology and innovation is solely the domain of young white males focused on social networking problems to make money for the benefit of investors. I am so happy to have seen this on the heels of such a terrible interview.
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.
What attracts the fish to the tube? The ladders work by providing some water that is going down stream slowly it is an obvious path. If there is no water to swim upstream against I don't understand why a fish would enter a random tube.
At about 88 secs in the second video[1] they show the inside of some sort of "trap" for the fish where water flows rapidly over a grate (and claim "volitional entry"). But I agree it's still an open question whether you could mitigate the fish's behavior effectively.
Salmon will swim towards turbulence (as part of a simple navigational strategy) so you can get them to swim into something using that. However, as with fish ladders, I expect it isn't 100% effective.
Source: my dad has built some fish hatchery equipment including volitional entry devices.
I've watched all the videos and I still can't understand how that thing can possibly work. They say it creates vacuum and transports things using atmospheric pressure, but both ends of the tube are open! What vacuum are they talking about? Is there a pump at one end sucking air? Am I looking at an elaborate prank?
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.
This device in its usefulness reminds me the squid gun of the infamous Vector superhero from Despicable Me. Normal people build cascades around dams for salmon. Once built these require zero maintenance.
I think for specific situations this can be useful. In the final video they show a 'holding tank' the salmon eventually get to and are then hand transported through the building to the next body of water.
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.
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjourna...
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