Captive coral adaptations

[Moontanman]

Is it known that coral that has been raised in captivity change their forms and are easier than wild caught corals to grow and propagate in captivity. The longer they are propagated in captivity the easier they are to grow, is this adaptation simply individual corals growing to meet the demands of their enviroment or is it actual genetic evolution to adapt to changing conditions? Coral is most often propagated by growing cuttings rather than by sexual reproduction.

[Essay]

is this adaptation simply individual corals growing to meet the demands of their enviroment or is it actual genetic evolution to adapt to changing conditions?

Plants radically change their form in domestic environments (but animals do too).

 

I think this is both "growing to meet the demands" and NOT genetic evolution, BUT epigenetic modification.

:confused: Wow, is that an akward sentence?

 

My point is to focus on epigenetics, which can account for the changes without the need to invoke the slower, and more 'random,' "natural selection."

 

...or put another way; most of the variation you see in different generations is already contained within their individual genetic compliments, and is not due to change or pre-existing variation across the genome.

 

The expression of that variation is controlled by epigenetics (and probably "crypto-genetic mechanisms" also).:hihi:

 

Does this make sense (and sound right)?

:)

[Moontanman]

Plants radically change their form in domestic environments (but animals do too).

 

I think this is both "growing to meet the demands" and NOT genetic evolution, BUT epigenetic modification.

:confused: Wow, is that an akward sentence?

 

My point is to focus on epigenetics, which can account for the changes without the need to invoke the slower, and more 'random,' "natural selection."

 

...or put another way; most of the variation you see in different generations is already contained within their individual genetic compliments, and is not due to change or pre-existing variation across the genome.

 

The expression of that variation is controlled by epigenetics (and probably "crypto-genetic mechanisms" also).:hihi:

 

Does this make sense (and sound right)?

:)

 

It does make sense and I wonder if coral will be more adaptable in the wild than most people seem to think. Coral that is raised in captivity grows in warmer water and under much less than the ideal conditions often sited as nesesarry for coral growth. In captivity coral grows quite rapidly, some grow several inches in a year and a saleable peice of coral can be grown in as little as three months. A really impressive cluster or coral head can be grown in a year under aquarium conditions.

[Not half- but whole!]

I would say you have some unique "pseudo-evolution" occurring in captive coral propagation. While there is no sexual reproduction going on, you do have selection for the most appropriate polyps , a survival of the fittest. The polyps most adapted to the tank conditions thrive, and out-compete the other polyps. a thinning of the heard so to speak.

Reef tanks are optimally kept in very specific conditions, and many tanks are very close replicas of each other (at least chemically). Captive propagation is essentially selecting for the individuals that fit these criteria.

There may even be a genetic bottleneck on the horizon as more and more corals are propagated asexually (although sexual propagation is starting in some advanced tanks).

[Moontanman]

I would say you have some unique "pseudo-evolution" occurring in captive coral propagation. While there is no sexual reproduction going on, you do have selection for the most appropriate polyps , a survival of the fittest. The polyps most adapted to the tank conditions thrive, and out-compete the other polyps. a thinning of the heard so to speak.

Reef tanks are optimally kept in very specific conditions, and many tanks are very close replicas of each other (at least chemically). Captive propagation is essentially selecting for the individuals that fit these criteria.

There may even be a genetic bottleneck on the horizon as more and more corals are propagated asexually (although sexual propagation is starting in some advanced tanks).

 

I am wondering if this pseudo-evolution occurs in the wild as well? If so will wild corals be able to adjust to the changing conditions in the ocean better than is now projected? Captive Reef tanks are not very close to the ideal conditions in the ocean, often they are much warmer and contain higher levels of nutrients.

[Not half- but whole!]

I think in the wild you would have less selective asexual propagation. Those that are fragging their corals are maintaining if not ideal conditions, probably very consistent conditions. Many reef tanks now run VERY low in terms of nutrient load in the water (and probably why some previous "bullet-proof" corals from 20 years ago now do horribly in many tanks, such as the elegance coral). With the heavy skimming and technical sterilization that many tanks have the microfauna is absent.

 

I have seen data (that I have drawn a complete blank on the source, perhaps Coral Magazine) that there have been some very surprising re-colonization of areas that had bleached.

[Moontanman]

I think in the wild you would have less selective asexual propagation. Those that are fragging their corals are maintaining if not ideal conditions, probably very consistent conditions. Many reef tanks now run VERY low in terms of nutrient load in the water (and probably why some previous "bullet-proof" corals from 20 years ago now do horribly in many tanks, such as the elegance coral). With the heavy skimming and technical sterilization that many tanks have the microfauna is absent.

 

I have seen data (that I have drawn a complete blank on the source, perhaps Coral Magazine) that there have been some very surprising re-colonization of areas that had bleached.

 

I would question the low level nutrient conditions in reef aquaria compared to wild reefs. When I had reef tanks I used algae scrubbers to remove nutrients and the flow through my skimmers was held to very slow in a separate sump. I also used deep (live) sand beds collected from the wild. These things resulted in lots of plankton being released at night and probably caused a higher than perfect nutrient load but the small polyp stony corals did quite well. I do know that most reef tanks run quite a bit warmer than most reefs do. When I was growing coral I kept my tanks in the low to mid 70's most of the people I knew that kept coral kept their tanks in the high 70's to low 80's and even higher in some cases. I agree that constant conditions are as important as correct conditions. I have read about the re-colonization of bleached corals. I hope it turns out to be more extensive than we now know.