Coral sexual reproduction question.

[cooljackal]

I've read a lot of articles explaining the yearly sexual reproduction of coral reefs. They explain the process but I haven't seen it happen in captivity. Is it because we don't know much about the specific conditions that must be met? I wonder when (or if) we are able to do this, it would be amazing.

[Crakeur]

I saw oral sex, came in and realized I was simply seeing what I wanted to see.

 

since I'm here... do a search on reproduction. there were, a while back, some links posted with regards to reproduction in tanks. I think it is simply the difficulty in producing the ideal conditions (ie natural reef conditions) that would foster sexual reproduction in a tank. I'm curious to know if any major aquariums even experience it. Might be worth a phone call or email.

[tinyreef]

y'know i saw a pic of a brooding xenia on blane perun's commercial site. he's been pretty successful in aquaculturing so he may have some insights (as would some of the livestock sponsors here, successful aquaculturists in their own right).

 

excess protein intake and energy requirements are basically shunted to the reproductive process imo. if you can feed your corals well and get 'em in the mood (moonlight, wave action, mood music, temp., booze, chemical triggers, etc.) they should spawn, in theory. :x

[chvynva916]

I worked on a tank in which pocillipora kept popping up everywhere. I assume this was the result of a spawn.

[RobD]

Originally posted by cooljackal

I've read a lot of articles explaining the yearly sexual reproduction of coral reefs.  They explain the process but I haven't seen it happen in captivity.  Is it because we don't know much about the specific conditions that must be met?  I wonder when (or if) we are able to do this, it would be amazing.

 

One of the factors that is supposed to help the timing of coral spawn in captivity is moonlight cycle simulation. You might find some hits on this, if you do an overall web search. Also, I'm sure that I've seen documentary footage showing this in the wild, you might be able to find that on DVD through Netflix, but I cannot confirm the details for you.

 

The short answer is that I think many tanks don't simulate lunar cycles so they don't give the tank the queues they need to spawn. That would be my guess on why it's not common in captive reefs.

[brahm]

Stuff like this gets me thinking.. Maybe there are more upsides to keeping a tank by a window then there are downsides... The Natrual Sunlight, and Moonlights, may present a less captive assocation with the corals and the enviroments we enclose them in. Granted baking your tank on a really hot day is a BIG downside.

[cooljackal]

I guess if you keep the water conditions just right, and are a reef freak. You may come up with an intense enough light source (multiple halides) with the correct filters for the types of corals you are keeping and have the light cycles computer controlled so that they match the real light cycle. Ofcourse you would need light that can fade but also create the right moonlight. You may just get your corals to spawn in september or something.

[Dingo]

/*puts on cheesy oracle hat*/

 

You will breed with your corals during the next full moon.

 

/*removes hat and places reef tank in bedroom*/

[RichMacys]

Originally posted by chvynva916

I worked on a tank in which pocillipora kept popping up everywhere.  I assume this was the result of a spawn.

 

pocillipora will eject polyps especially when placed or moved in the the tank.

[powerofslack]

Used to work in a coral spawning research lab, although my project didn't have a lot to do with that particular stuff- according to those guys, it's all about the light cycles- the corals time very strictly it by both the sunlight cycle (for time of year), and the moonlight cycle (to make sure they're all really synched up)- so most years they would go to collect/film stuff the first full moon in April, and one year they had to plan for two conseuctive full moon trips to be sure they had the correct one, since the full moon straddled the optimum time of year- of course all of the corals still knew which one it was and all spawned at the same time- so from what I've heard worst case you would need a timer on your main lights to simulate seasonal changes in day length as well as a timer controlled moonrise/moonset/moon phase simulation light at night to be sure to get spawning- I don't know whether anyone has succeeded using less than these full requirements- I do know that the slime that corals eject when stressed looks nothing lke what happens when they eject gametes for spawning. Hope this is helpful!

[texan1]

Reviving this old thread, I would think that the fact that corals spawn during the full moon has very little to do with the LIGHT the moon is putting off, but more to do with the gravitational effects of the full moon. These being higher tides and lower tides, and more drastic tidal changes.

What do y'all think?

[powerofslack]

Turns out, no. (Sorry to break the news!) So, the gravitational effects of the moon due to r^2 regular old gravity are in fact not really felt worth a crap by anything on the Earth, when compared to say the gravity of the Earth itself. Tidal force is an r^3 thing, which is why even though it's the much bigger and farther away Sun that the Earth revolves around, it's the smaller but closer Moon that causes the tides. Tidal forces are "noticed" by things in proportion to their own length scale, which is sort of why ponds don't really have tides to speak of, and why something the size of even a large coral would be hard pressed to sense tidal forces. Finally and most importantly, this part is hard to explain without being able to draw a picture (okay, okay, so I'm too lazy to scan one in but you can Google it!), but there is not any direct correlation between the phases of the moon and the timing of the tides that is consistent from year to year. Turns out, it's the light after all!

[birdman204]

actually, I think it's both. the reason for full and new moons are due to the earths position between the moon and the sun. Both of the gravitational forces can be felt on earth as exampled by the earth rotating around the sun, and the moon rotating around the earth. So why is it then that the Great Barrier all spawn on the same day at the sime time of year? They do it when the tidal phase shifts, due to the earth moving closer and farther from the sun, the moon and the sun pull in unison to create giant tides.. There are places in south america where tides can go as far as 200 miles inland! So it appears that both play factors. In aquaria the best thing you can do is to provide natural moonlight phasing because it is believed that the gravitational forces can still be felt in our tanks...

Although Fant brought up an interesting point to me, and that was corals need to reach a certain size before sexual maturity, and I am not sure if our nano-s provide adequate space.

 

my .02 cents. I just hope it makes sense.

[Fant]

Might need to be a certain size.. i duno for certain..

[bgoode]

Here's a couple articles by Eric Borneman on the subject. Unfortunately, it could be any number of things. It will be cool when corals spawn regularly in captivity.

http://reefkeeping.com/issues/2003-05/eb/index.htm

http://reefkeeping.com/issues/2003-06/eb/index.htm

[powerofslack]

Well, hmmm. There's a little more to the phase/tides thing than I really said list time- specifically, the ellipticity of the Moon's orbit is locked to the radial vector of the Earth's orbit, which means that the times that the Moon is slightly closer to the Earth or farther away for the Earth (during the Moon's orbit around the Earth) actually correspond with the phases of the moon, so that the lowest low tides and highest high tides in each month will always correspond to a specific phase of the moon, for example. Because of this, it might be hypothetically possible (although I'd speculate it's unlikely, but hey who knows) for corals to sense these especially low or high tides via changes in static pressure as a way of sensing the phase of the moon, but it's pretty improbable that they could sense tidal forces directly. On another note, the change in the distance between the Sun and the Earth as the Earth rotates around the Sun doesn't affect the tides at all. In fact as I mentioned, tidal forces and gravitational forces are quantitatively very different things, (one is an r^3 force, the other r^2), and because of this, as mentioned, the Sun has very little to do with the tides at all in fact. Hey congrats on tank of the Mo! It looks great.

[birdman204]

Good points power. I would be suspect to say it is just the moon, The spawning occurs at the same time of the year, where we have 13 moonphases through a year. My statement was simply a theory, The time of year could be triggered by a number of things, water temp, currents, the distance of the earth from the sun, and the distance of the moon from the earth. They may all be indirect , but they all have a direct affect. And some scientists have noticed that animals in the tank react to the tide changes in aquaria regardless of lighting or flow. I am guessing it is something to do with evolution , you know, dolphins navigating by magnetic fields and what not... There are a lot of things the corals aren;t telling us

Thanks, I need gil to come over for more pics. some of my stuff has really colored up nicely under the 20K.

[powerofslack]

Oh, (I mean D'oh!) I realize I made a mistake and misunderstood what you were trying to say to some extent, because I had a hidden assumption and I took it for granted that everyone else had the same assumption too! With the sun, it's very very likely to be the light thing, more specifically the length of the days as this changes throughout the year. The mechanisms for biological regulation due to changes in day length have been exhaustively studied in plants like deciduous trees etc., and even in animals, including both ones that hibernate, and those that simply store more fat as winter approaches, and in all of the studied cases there is a clear explanation for how the process is regulated by changes in the length of the days right down to the molecules involved and all. However, in at least some plants changes in temperature also help to reinforce this regulation, although these plants also have the canonical day-length based regulation. So anyway my incorrect assumption was that the whole discussion was just about "how do they know it's the full moon", and not also about "how do they know which specific full moon it is", because I guess I figured that, although as far as I know this hasn't been shown in corals (didn't sound like it from the Borneman articles), the part about what time of the year it is is probably regulated the same way it is in everything else: by the length of the day, which made me misunderstand what you were saying a little. Come to think of it, maybe knowing how this works for day length is part of what makes me biased in my hunch that even with the "when is the Moon full" part it's the light thing, although hey who knows. Like I said temperature is at least a possibility by precedent for the time of year thing, although given the temps on reefs my money is on day length still. Anyway now at least I hope I'm unconfused enough that we're talking about the same thing and I know what everyone's trying to say. You know what, maybe I'll email my old boss who does coral research stuff and see if he knows of any research I'm not aware of about this that I couldnt dig up on the net. You never know... If I have any luck I'll bore you guys with it as soon as I hear back!

[birdman204]

Yeah. I love discussions like this. I am gonna go home and watch the coral seas again on blue planet. A little x-mas gift I rcvd that touches on this subject.

I beleive that all of these factors contribute, maybe not directly to the animal itself but maybe the environment that affects the changes the animal feels. That is what needs to be done to closely replicate a natural environment. As for the gravitational pull , mother nature handles that part, so we need to worry about lighting, diet, and a muriad of other things to get this events to occur more frequently in home aquaria.

[birdman204]

http://www.gsfc.nasa.gov/scienceques2001/20011221.htm

 

Interesting info. In brazil at the amazon, only when the sun AND the moon align do they get tidal bores that reach as far inland as 200 miles !!! holy cow!!!! Anyways, Just some more info for the gravity theory. Again still probably alittle bit of everything.