Nothing like a good debate!!!
L46 Leave alone !!
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Dan D' Man
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I like the key words "not disturbed". That would be great...I wish it would only happen that way.McEve wrote:Given the slow reproduction rate of the Zebra I can't see how they would manage to replenish the numbers in only 2-3 years. That's only one generation. Surely it would take at least 3-4 generations before they have reestablished any consiberable amount of fish, so we're talking 10 years rather than 2-3, if they are left alone and not disturbed in any way?
In my opinion, the Xingu Zebra population is not starting from F0 parents like private breeders. We must assume that the natural population has a cross-section of anything from fertilized eggs, young fry, sub-adults & full sexually active adults. So it is an on-going cycle, with F1's-Fx being produced year-round (hopefully). What can be considered a healthy population and how long before it reaches that stage? I think that is a question that biologist should answer & counsel Brazil's govt
McEve,
Doesnt numbers in 2 years depend on whats left now.The more that are left, the quicker they will replenish.
If (and thats a big IF) each pair have 2 clutches per season of approx 15 youngsters per brood ie 30 per pair. After a year if there have been no fatalities, there will be 15 times more zebras.
If (just for the sake of this calculation)there are a 1000 adults left ( half of each sex) , theoretically you get 15000 after a year.
However if there are a 100 left or 50 pairs,you get 1500 after a year, so the more that are removed at this time the worse it gets.
These figures are dependent on the calculation above and of course will vary on the numbers in each brood and the number of broods per season.
If for example there is only one brood per season and only 10 survive this gives you 5 times more zebras after a year.
Theoretically this number will double the following year.The year after that, the babies born 2 years previously will be learning about the birds and the bees, and help boost the numbers yet again.
Regards,
Des.
Doesnt numbers in 2 years depend on whats left now.The more that are left, the quicker they will replenish.
If (and thats a big IF) each pair have 2 clutches per season of approx 15 youngsters per brood ie 30 per pair. After a year if there have been no fatalities, there will be 15 times more zebras.
If (just for the sake of this calculation)there are a 1000 adults left ( half of each sex) , theoretically you get 15000 after a year.
However if there are a 100 left or 50 pairs,you get 1500 after a year, so the more that are removed at this time the worse it gets.
These figures are dependent on the calculation above and of course will vary on the numbers in each brood and the number of broods per season.
If for example there is only one brood per season and only 10 survive this gives you 5 times more zebras after a year.
Theoretically this number will double the following year.The year after that, the babies born 2 years previously will be learning about the birds and the bees, and help boost the numbers yet again.
Regards,
Des.
Last edited by Des on Wed May 25, 2005 7:08 pm, edited 1 time in total.
Sojapat,
My little ranting about the birds in Australia was only made to show that we may not agree with the laws of the land they are made in but we have to abide by them.
I am on your side of the fence and dont agree with any illegal activity/poaching.
Dan D'Man,
I believe that this post was started due to a member stating that they were due to import a batch of Zebras from Brazil into the UK.
Although you do have a point about the future dangers of the dam, which a lot of us knew about, some of us do not agree with the importation of livestock that are currently on a Banned list.
Regards,
Des.
My little ranting about the birds in Australia was only made to show that we may not agree with the laws of the land they are made in but we have to abide by them.
I am on your side of the fence and dont agree with any illegal activity/poaching.
Dan D'Man,
I believe that this post was started due to a member stating that they were due to import a batch of Zebras from Brazil into the UK.
Although you do have a point about the future dangers of the dam, which a lot of us knew about, some of us do not agree with the importation of livestock that are currently on a Banned list.
Regards,
Des.
This is given the best possible scenario, with no fatalities and optimal conditions (no preying fish, no disease, in short - no fatalities at all)Des wrote:McEve,
Doesnt numbers in 2 years depend on whats left now.The more that are left, the quicker they will replenish.
If (and thats a big IF) each pair have 2 clutches per season of approx 15 youngsters per brood ie 30 per pair. After a year if there have been no fatalities, there will be 15 times more zebras.
If (just for the sake of this calculation)there are a 1000 adults left ( half of each sex) , theoretically you get 15000 after a year.
However if there are a 100 left or 50 pairs,you get 1500 after a year, so the more that are removed at this time the worse it gets.
These figures are dependent on the calculation above and of course will vary on the numbers in each brood and the number of broods per season.
If for example there is only one brood per season and only 10 survive this gives you 5 times more zebras after a year.
Theoretically this number will double the following year.The year after that, the babies born 2 years previously will be learning about the birds and the bees, and help boost the numbers yet again.
Regards,
Des.
It rarely works like that.... We agree one one thing, the more that are left the more there will be to increase the population
But when a specie is on an endangered list, it usually implies more than 2-3 years to regrow a healthy and stable population....I do not nessesarily agree that one should follow the law simply because the law is there. There's too many reasons for a law to be passed - financial (most common) politicial prestige power so forth - protecting the enviroment usually comes pretty far down the list. which is why so many enviromentalists end up in jail or with huge fines, as they use civilian disobidience to get their point across when they find a law is wrong, (not surving the purpose, or working as intended and then taking ages to change). Often they get the world (read "press"
) to take notice and actually manage to get things changed as well. Cudos to them for that - even though they're not always right either.I realize what I say now might be a very hot potato indeed, but should under no circumstances be interpreted towards me defending illegal imports of any endangered specie - as I do not!
Hmmm... I'm not even sure what we're discussing anymore here, there's so many side tracks here
Oh yes, "leave the L46 alone". Absolutely! but I would be very interested in seeing a report of how the Zebras future is going to be protected! it would set my heart at rest to see the plans for the preservation og the Zebra. And that's a big part of the problem isn't it - there's no official and reliable information released, so people end up speculating - which ends up in rumours 
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Dan D' Man
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Rob; that's great news from a group trying to work with IBAMA!
On an ideal world, IBAMA should commision a group of local fishermen to catch & relocate X number of Zebras to other locations within Brazil that would not be threatened by any type of construction (destruction?) On a real world: this cost money & resources. Keeping it real, unless private groups gather enough publicity, funds & political influence, this won't happen.
On an ideal world, IBAMA should commision a group of local fishermen to catch & relocate X number of Zebras to other locations within Brazil that would not be threatened by any type of construction (destruction?) On a real world: this cost money & resources. Keeping it real, unless private groups gather enough publicity, funds & political influence, this won't happen.
Hi McEve,
Thanks for your answer . My "quick" calculations were worked out on a Hypothetical situation. Researchers out there in the Xingu, should be the ones to work out the numbers. Nobody knows what the exact numbers of L046 that are left in the Xingu . What we do know is that there are now very few indeed, hence the need for IBAMA to put the L046 on the Banned list late in Dec 2004.
Sojapat, who was in the Xingu late last year , stated I think, that the fishermen were only coming back with one or 2 of the L046 after a whole days fishing/catching.
For the sake of some of our newer members ,for more information on the Official RED LIST ,have a look here:
http://www.zebrapleco.com/forum/viewtop ... c&start=15
What we should not do ,is cloud the issue with the dam scenario.There is a BAN NOW ( since late Dec 2004) and we, as you quite rightly say should not be defending the illegal importation of endangered species.Therefore the title of this Forum : Keep the L046 in the Xingu.
Rob,
I think it would be great if a spokesperson for these conservationists could contribute to this forum.
Regards,
Des.
Thanks for your answer . My "quick" calculations were worked out on a Hypothetical situation. Researchers out there in the Xingu, should be the ones to work out the numbers. Nobody knows what the exact numbers of L046 that are left in the Xingu . What we do know is that there are now very few indeed, hence the need for IBAMA to put the L046 on the Banned list late in Dec 2004.
Sojapat, who was in the Xingu late last year , stated I think, that the fishermen were only coming back with one or 2 of the L046 after a whole days fishing/catching.
For the sake of some of our newer members ,for more information on the Official RED LIST ,have a look here:
http://www.zebrapleco.com/forum/viewtop ... c&start=15
What we should not do ,is cloud the issue with the dam scenario.There is a BAN NOW ( since late Dec 2004) and we, as you quite rightly say should not be defending the illegal importation of endangered species.Therefore the title of this Forum : Keep the L046 in the Xingu.
Rob,
I think it would be great if a spokesperson for these conservationists could contribute to this forum.
Regards,
Des.
Hi
A lively debate!
I totally agree with the ban in principal. Zebras should be allowed to recover for as long as they need to.
However, this export ban is just so hypocritical when the Brazilian government is seemingly allowing this dam to be built. Whats the point of allowed the L046 and other species in this area to rest and recover when the dam will just wipe them out? This is why I personally would prefer to see (if at all possible) as many species relocated to other areas. I would also personally prefer to have the last zebra plecs distributed between the successful L046 breeders around the world, rather than left to fend for themselves in the Xingu....IF....the dam is built. Obviously if the dam is not going to be buitl, we should leave them well alone and make do with the tank bred L046s.
Regards
Tom
A lively debate!
I totally agree with the ban in principal. Zebras should be allowed to recover for as long as they need to.
However, this export ban is just so hypocritical when the Brazilian government is seemingly allowing this dam to be built. Whats the point of allowed the L046 and other species in this area to rest and recover when the dam will just wipe them out? This is why I personally would prefer to see (if at all possible) as many species relocated to other areas. I would also personally prefer to have the last zebra plecs distributed between the successful L046 breeders around the world, rather than left to fend for themselves in the Xingu....IF....the dam is built. Obviously if the dam is not going to be buitl, we should leave them well alone and make do with the tank bred L046s.
Regards
Tom
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Dan D' Man
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Rob, tell Andrew that I'll volunteer! Maybe they can send some govt-approved colonies of Zebras for experimental relocation in my pond! Seriously, I'm going to ask my brother what is done for similar situations. My brother in Panama has been involved in constructions of dams, water locks, etc and he is an aquarist too.. he might have some insight.
Seriously, I'm going to ask my brother what is done for similar situations. My brother in Panama has been involved in constructions of dams, water locks, etc and he is an aquarist too.. he might have some insight.
I know that for the Lake Victoria project they were looking into ways of replacing lost species of cichlids in numbers large enough to support redistribution.
I would think in this instance they'll be doing research into the conditions the zebras require for continued population levels that will stay self supporting. Keeping in mind that most of the people doing that type of research won't have any experience on the reproductive needs of the fish, some of the information contained here could really be invaluable.
On that note, count me in if they need anything I can do from here Rob
.
Barbie
I would think in this instance they'll be doing research into the conditions the zebras require for continued population levels that will stay self supporting. Keeping in mind that most of the people doing that type of research won't have any experience on the reproductive needs of the fish, some of the information contained here could really be invaluable.
On that note, count me in if they need anything I can do from here Rob
.Barbie
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Dan D' Man
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Rob, I got some feedback from my brother regarding some of the effects of ecology on the food chain. Can you ask Andrew if he knows of any natural predators of the Zebras in the Xingu? Like would Gold Nugget Plecos attack Zebras, eat their eggs,etc. We baby our L046's so much, we wouldn't think of having behemoths together with Zebras, but that is what happens in nature. One point is when a river is affected, the stronger survive and become stronger predators on weaker species just to survive. There's a lot more info, but I better PM you one of this days. The reality of building dams & politics is not for the weak of heart.
