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Coral Spawning

By Various Authors. Posted to reef-l emailing list, Wednesday the 12th to Monday the 17th of July 2000.

Andy Hipkiss

Has anybody got any ideas on what parameters need to be in place to encourage SPS corals to spawn? I've read the bits in F&N and it looks like its a bit hit and miss.

Is it purely a case of the correct moon cycle, or is it also temperature dependent?

Has anybody got any good online references to spawning events in the wild? Perhaps cyclical tidal effects apply?

I guess what I'm asking is, from the top, what happens in the wild and how can be start to mirror the environment in our tanks.

Sorry for such a broad question!

Eric Borneman

Spawnings in corals are dependent on quite a number of things. It's time to do away with this whole moonlight myth.

Corals produce gametes when they are energetically able to do so. In other words, they have to be healthy, non-stressed, and have enough surplus of energy through feeding to produce them. That's the first thing.

Corals also have to be of a certain age or size to be reproductively mature. In other cases, a certain polyp density or area must be present. For some octocorals, like female Sarcophyton spp., you may have to have a decade old colony. For some Acropora spp., the branches will need to be almost a foot long. Others may mature within a year or two - like some Xenia spp.

In some cases, if a colony is collected from the wild with spermaries or ovaries already in place on the mesenteries, they may spawn in response to stress. Or, they may resorb these tissues.

Not all corals are broadcast spawners. Some are internal brooders. Some are surface brooders. Some produce asexual planulae. Some, like Pocillopora damaicornis, may be broadcast spawners in some locations, broooders in others. Some may do both from the same location, depending on local conditions. Those that brood typically have different life histories. Brooders may produce planulae once per year, or once per month, or several times per year.

So, among the broadcast spawners, what happens? Temperature is the determining factor in most locations for corals that are sexually mature and when energetically able to do so. The gradual warming of the water signals the production of gonads. If there are anomalous water conditions, some colonies may miss a season. Or they may miss others' mass spawning by a month, a week, or two months, etc. In locations like the Red Sea where odd temperatures can occur, the process probably occurs in different ways, explained below. However, if all things are ideal, and temperatures follow normal cycles, and the colonies are ripe, then they need a trigger. Here, such corals tend to follow lunar cues - or so it seems. Its not always the same, and there is no given time of the moon that all corals spawn. It varies depending on location and species. Furthermore, there isn't enough moonlight for corals to detect the photons. In fact, corals can't detect light at all. What happens on cloudy nights? Corals spawn anyway. Tidal cues may be important here. Endogenous or circadian rhythms may also be important.

But, zooxanthellae can detect light.

And here is the interesting part. In the Red Sea, in certain locations, tides and temperatures are highly aberrant. There is only one constant - day length. If you recall from basic biology, plants tend to follow two patterns in their flowering, fruiting, growth and leaf-color patterns - long day/short night plants that react only when the night is shorter than a critical value and short day/long night plants that react only when the night is longer than a criticial value. They produce chemical substances at that time that trigger behavior. Zooxanthellae, thus, may be responding not to moonlight levels but to day/night-length values and thus triggering the release of coral gametes. Further evidence? How the heck would a Dendronepthya or Tubastraea in a cave "know" what the moon cycle was like?

The chemical signalling is also likely responsible for the release in other species. For example, spawning of zooxanthellate corals may trigger spawning in clams, which triggers spawning in azooxanthellate corals, which triggers spawning in echinoderms, etc...

So, you ask for references? There are too many, but Yusef Fadlallah has a good review of the spawning patterns of many corals in the journal Coral Reefs, and there is a good secondary review in Dubinsky's Coral Reefs V 25 or Ecosystems of the World. If that isn't sufficient, contact me after you have locted and read these, and I will be happy to produce more than you probably care to read.

Mike Kirda

The Fadlallah ref Eric talked about is pre-1990, I think, therefore not in this database. Here are some post-1990 ones...

   SEARCH STRING su(coral spawning)

DATABASE ArticleFirst


Record 5

      AUTHOR Slattery, M; Hines, G A; Starmer, J; Paul, V J
       TITLE Chemical signals in gametogenesis, spawning, and larval 
              settlement and defense of the soft coral Sinularia polydactyla
JOURNAL NAME Coral reefs  journal of the International Society for Reef 
              Studies.
  VOL, ISSUE Volume 18, Number 1
       PAGES pp. 75     
        YEAR 1999
        TYPE Article
        ISSN 0722-4028

Record 10

      AUTHOR Sakai, K
       TITLE Gametogenesis, spawning, and planula brooding by the reef 
              coral Goniastrea aspera (Scleractinia) in Okinawa, Japan
JOURNAL NAME Marine ecology progress series.
  VOL, ISSUE Volume 151, Number 1-3
       PAGES pp. 67     
        YEAR 1997
        TYPE Article
        ISSN 0171-8630

Record 12

      AUTHOR Fadlallah, Yusef H
       TITLE Synchronous spawning of Acropora clathrata coral colonies from 
              the western Arabian Gulf (Saudi Arabia)
JOURNAL NAME Bulletin of marine science.
  VOL, ISSUE Volume 59, Number 1
       PAGES pp. 209    
        YEAR 1996
        TYPE Article
        ISSN 0007-4977
  J ALT NAME Bulletin of marine science of the Gulf and Caribbean

Record 14

      AUTHOR Babcock, Russ
       TITLE Synchronous multispecific spawning on coral reefs Potential 
              for hybridization and roles of gamete recognition
JOURNAL NAME Reproduction, fertility, and development.
  VOL, ISSUE Volume 7, Number 4
       PAGES pp. 943    
        YEAR 1995
        TYPE Article
        ISSN 1031-3613
  J ALT NAME Clinical reproduction and fertility Australian journal of 
              biological sciences

Record 15

      AUTHOR Coll, J C; Leone, P A; Bowden, B F; Carroll, A R; 
              Konig, G M; Heaton, A; Nys, R de; Maida, M; Alino, P M; 
              Willis, R H; Babcock, R C; Florian, Z; Clayton, M N; 
              Miller, R L; Alderslade, P N
       TITLE Chemical aspects of mass spawning in corals. II. (-)-Epi-
              thunbergol, the sp rm attractant in the eggs of the soft coral 
              Lobophytum crassum (Cnidaria
JOURNAL NAME Marine biology.
  VOL, ISSUE Volume 123, Number 1
       PAGES pp. 137    
        YEAR 1995
        TYPE Article
        ISSN 0025-3162

Record 16

      AUTHOR Gittings, S. R.; Inglehart, W. A.; Rinn, G. S.; Dokken, Q. R.
       TITLE Coral mass spawning on the flower garden banks, NW Gulf of 
              Mexico
JOURNAL NAME Bulletin of marine science.
  VOL, ISSUE Volume 54, Number 3
       PAGES 1076
        YEAR 1994
        TYPE Article
 ISSUE DESCR Symposium on Florida Keys Regional Ecosystem
        ISSN 0007-4977
BL SHELFMARK 2866.990000
  J ALT NAME Bulletin of marine science of the Gulf and Caribbean

Record 17

      AUTHOR Babcock, R. C.; Wills, B. L.; Simpson, C. J.
       TITLE Mass spawning of corals on a high latitude coral reef
JOURNAL NAME Coral reefs  journal of the International Society for Reef 
              Studies.
  VOL, ISSUE Volume 13, Number 3
       PAGES 161
        YEAR 1994
        TYPE Article
        ISSN 0722-4028
BL SHELFMARK 3470.325000

Record 18

      AUTHOR Van Veghel, M. L. J.
       TITLE Reproductive characteristics of the polymorphic Caribbean
reef 
              building coral Montastrea annularis I. Gametogenesis and 
              spawning behavior
JOURNAL NAME Marine ecology progress series.
  VOL, ISSUE Volume 109, Number 2/3
       PAGES 209
        YEAR 1994
        TYPE Article
        ISSN 0171-8630
BL SHELFMARK 5373.904000

Record 20

      AUTHOR Coll, J. C.; Bowden, B. F.; Meehan, G. V.; Konig, G. M.; 
              Carroll, A. R.
       TITLE Chemical aspects of mass spawning in corals.  I.  Sperm-
              attractant molecules in the eggs of the scleractinian coral 
              Montipora digitata.
JOURNAL NAME Marine biology.
  VOL, ISSUE Volume 118, Number 2
       PAGES 177
    PUB DATE January
        YEAR 1994
        TYPE Article
        ISSN 0025-3162

Record 21

      AUTHOR Hayashibara, T.; Shimoike, K.; Kimura, T.; Hosaka, S.; 
              Heyward, A.; Harrison, P.; Kudo, K.; Omori, M.
       TITLE Patterns of coral spawning at Akajima Island, Okinawa, Japan.
JOURNAL NAME Marine ecology progress series.
  VOL, ISSUE Volume 101, Number 3
       PAGES 253-262
    PUB DATE November 25
        YEAR 1993
        TYPE Article
        ISSN 0171-8630
    LANGUAGE English

Record 22

      AUTHOR Babcock, B.; Mundy, C.; Keesing, J.; Oliver, J.
       TITLE Predictable and unpredictable spawning events in situ 
              behavioural data from free-spawning coral reef invertebrates.
JOURNAL NAME Invertebrate reproduction & development.
  VOL, ISSUE Volume 22, Number 1-3
       PAGES 213-228
    PUB DATE December
        YEAR 1992
        TYPE Article
 ISSUE DESCR Economic and Applied Aspects of Invertebrate Reproduction
        ISSN 0792-4259
  J ALT NAME International journal of invertebrate reproduction and 
              development
    LANGUAGE English

Record 23

      AUTHOR Harrison, Peter
       TITLE Coral Spawning on the Great Barrier Reef.
JOURNAL NAME Search.
  VOL, ISSUE Volume 24, Number 2
       PAGES 45-47
    PUB DATE March
        YEAR 1993
        TYPE Article
    ABSTRACT On certain predictable nights of the year, many species of 
              coral spawn simulataneously
        ISSN 0004-9549
  J ALT NAME Search (Sydney, N.S.W.) Australian journal of science
    LANGUAGE English

Record 24

      AUTHOR Ward, S.
       TITLE Evidence for broadcast spawning as well as brooding in the 
              scleractinian coral Pocillopora damicornis.
JOURNAL NAME Marine biology.
  VOL, ISSUE Volume 112, Number 4
       PAGES 641-646
    PUB DATE April
        YEAR 1992
        TYPE Article
        ISSN 0025-3162
    LANGUAGE English
  

Andy Hipkiss

Corals produce gametes when they are energetically able to do so. In other words, they have to be healthy, non-stressed, and have enough surplus of energy through feeding to produce them. That's the first thing.

So we're talking about carbohydrate availability (e.g. from leaky zooxanthellae?) Or (additionally) CHO, lipids and proteins from the water column?

Corals also have to be of a certain age or size to be reproductively mature.

That's clear.

In other cases, a certain polyp density or area must be present.

That's not so clear -) ..... Logically therefore, a skimmerless (or a carbon-less) tank would be appropriate since it implies that the coral colonies are chemically sensing each other (?).

For some Acropora spp., the branches will need to be almost a foot long.

I guess this is where I don't understand the cooperative nature of the individual Acropora animals. I need an "idiots guide" to what is a complex systemic scenario -o

So, among the broadcast spawners, what happens? Temperature is the determining factor in most locations for corals that are sexually mature and when energetically able to do so.

OK. So going by the various average seawater temperature charts I have seen, I need to get a precise chiller and controller and vary the average temp between (let's say) 24 and 28C?

They need a trigger. Here, such corals tend to follow lunar cues - or so it seems. Its not always the same, and there is no given time of the moon that all corals spawn.

Right. But it looks like I need to target the temperature control first.

In fact, corals can't detect light at all. What happens on cloudy nights? Corals spawn anyway. Tidal cues may be important here. Endogenous or circadian rhythms may also be important.

Or just the fact that tides follow lunar cycles away. IIRC, spawning happens shortly after the neap tide?

There is only one constant - day length. If you recall from basic biology, plants tend to follow two patterns in their flowering, fruiting, growth and leaf-color patterns - long day/short night plants that react only when the night is shorter than a critical value and short day/long night plants that react only when the night is longer than a criticial value.

The only problem I have with this is that (with the joys of the British weather), plants start their flowering(etc) cycle earlier if Spring (i.e. Higher temperature) comes early.

How the heck would a Dendronepthya or Tubastraea in a cave "know" what the moon cycle was like?

Indeed, I seem to recall some TV program commenting on the same species in the same area but some being a far greater depths (i.e. As you mentioned, unable to detect (via zoox., or otherwise)), still spawning on the same night.

The chemical signalling is also likely responsible for the release in other species.

Again we're looking at a skimmerless/carbon-less system?

Eric Borneman

So we're talking about carbohydrate availability (e.g. from leaky zooxanthellae?) Or (additionally) CHO, lipids and proteins from the water column?

Not really. Most of the photosynthate from zooxanthellae is carbon rich and is respired by the coral animal. Spermaries and ovaries are a lot of protein - nitrogen requiring and typically met through feeding and uptake.

That's not so clear -) ..... Logically therefore, a skimmerless (or a carbon-less) tank would be appropriate since it implies that the coral colonies are chemically sensing each other (?).

They'll sense each other anyway - there's only a few drops of water in an aquarium comparatively. The chemical signalling in spawning is probably mostly through compounds in the eggs once released and there may be others. I'm not sure if its in Mike's ref list, but there is an article called something like "Chemical control of spawning in Alcyonarean corals" if I recall correctly.

I guess this is where I don't understand the cooperative nature of the individual Acropora animals. I need an "idiots guide" to what is a complex systemic scenario -o

These are perforate corals and have complex connections between polyps. It's not really to do with the individual colony and sensing each other, its between colonies. Perhaps within, too. I'm not sure. The size factor has to do with age and maturity.

OK. So going by the various average seawater temperature charts I have seen, I need to get a precise chiller and controller and vary the average temp between (let's say) 24 and 28C?

Might help, but the temperature change may be somewhat hardwired by species and/or location. If you knew where the colony came from and could emulate those conditions, it would be best. Still, I would think that some degree of annual temperature cycling couldn't help but help.

Right. But it looks like I need to target the temperature control first.

No, first is making sure the colonies are old enough, fed enough, and have the capacity to produce gametes. Then the temperature, then the trigger, and to be sure if the species you are working with are spawners and use lunar cues as a trigger. As no one has really gotten this down to anything resembling a regular occurrence yet, this is logical guesswork only.

The only problem I have with this is that (with the joys of the British weather), plants start their flowering(etc) cycle earlier if Spring (i.e. Higher temperature) comes early.

I have seen plants flower in autumn after a hurricane, too.

Again we're looking at a skimmerless/carbon-less system?

nah. I doubt it will matter.

Keith Redfield

But neither one of you brought up the issue that most coral spawns will in general be a Very Bad Thing for the tank, and likely nuke the entire thing. Best done in multi-thousand-gallon systems with lots of standby filtration (or new water) available, i.e commercial facilities (Hmmm...I have multi-thousand gallon systems...)

Charles Delbeek showed some nifty ideas for propagating them by collecting spawn in the areas where they are tightly governed by the lunar cycle (GBR, PNG, etc).

Andy Hipkiss

But neither one of you brought up the issue that most coral spawns will in general be a Very Bad Thing for the tank, and likely nuke the entire thing.

Quite possible, however the spawning ought to be predictable and suitable "cleanup" measures at hand.

Equally and more importantly, the knowledge gained might be worth the grief ... I casually say, being quite along way away from being in that situation -)

Mike Kirda

Quite possible, however the spawning ought to be predictable and suitable "cleanup" measures at hand.

It is a simple matter of engineering. You have to be ready for the spawn, and that means having the ability to do a 100% water change. It is easily 'feasible', but will cost some coinage and space to do it right...

Personally, I'd look at having, say, a 500 gallon system plumbed into a 500 gallon reserve. 1000 gallons total and when the spawn is anticipated, you can close a valve and have 2 separate systems that have essentially the exact same water chemistry. Then when the spawn happens, you can do a 500 gallon water change (100%). Simple if you design the system right.

Eric Borneman

But neither one of you brought up the issue that most coral spawns will in general be a Very Bad Thing for the tank, and likely nuke the entire thing.

maybe. I don't think enough experience exists with mass spawnings in captivity yet to say one way or the other. I also think it will depend on just how nasty the individual species eggs might be or how much the oxygen levels might drop and for how long.

James Wiseman

It would also be pretty simple to collect coral spat out here in the Gulf of Mexico when the Flower Garden Banks spawn. This spawn occurs pretty much like clockwork every year (Very healthy reef to say the least). I think this would be a GREAT way to "harvest" some gametes in order to try to raise protected carribean corals.

Mike Kirda

I'm not sure if its in Mike's ref list, but there is an article called something like "Chemical control of spawning in Alcyonarean corals" if I recall correctly.

I don't think it was in there- the list is by no means complete. Once I did a search on 'spawning' and got back hundreds of references. Most of them about various fish. I'm not going to wade thru that many...

There are several articles recently that deal with eggs and the sperm chemo-attractants. When you think about it, spawning, in the larger sense, encompasses a lot of different areas. You need to look at coral nutrition, various cues, probably species composition on the reef, water chemistry vis-a-vis chemical cues, then fertilization and settlement strategies. Settlement is a whole other ball of wax...

Of course, you know this, but others may not have considered it fully. There are literally hundreds of articles that would fall under the header of 'spawning', but do not appear in the databases under this moniker due to the fact that the research is much narrower and focuses on only one small aspect of the greater topic 'spawning'. You are best to pull a few refs, and look at it's references. Notice researchers that seem to be working on the topic, then look for other articles that they have published. Sometimes you need to work backwards to uncover this stuff. Also, some databases (i.e. Web of Science) are scientific citation databases. So, if one of these articles are referenced once, you can see whom else has referenced it. This method has uncovered a lot of great nuggets for me...

Andy Hipkiss

Not really. Most of the photosynthate from zooxanthellae is carbon rich and is respired by the coral animal. Spermaries and ovaries are a lot of protein - nitrogen requiring and typically met through feeding and uptake.

Fine, so its definitely worth persevering with my feeding regime, which is mainly targeted at the micro-fauna/flora (i.e. I use various planktonic sources). However I'll probably pick everyone's' brains over this topic at a later date.

The size factor has to do with age and maturity.

My one question on this point is what's the life expectancy of an individual coral animal. Is it the maturity of the colony or the maturity of individual animals? I suspect the former as otherwise we could just chop a bit coral from the older part of the colony and have ready made spawning stock.

If you knew where the colony came from and could emulate those conditions, it would be best.

Well I know the area the older corals I have come from, and I've managed to find the data from that approximate area.

No, first is making sure the colonies are old enough,

True

fed enough,

Ah but that's a "how long is a piece of string" statement -) ... (Hopefully that's a US phrase as well)

As no one has really gotten this down to anything resembling a regular occurrence yet, this is logical guesswork only.

Indeed, but some of you guys have been far more diligent with your research than I, even though I've probably been in this hobby somewhere approaching yourself (+-5 years). (Self-flagulation moment!)

Eric Borneman

My one question on this point is what's the life expectancy of an individual coral animal. Is it the maturity of the colony or the maturity of individual animals? I suspect the former as otherwise we could just chop a bit coral from the older part of the colony and have ready made spawning stock.

Ah, the great debate that Ron, Dieter and I spent an hour discussing over beers in France a few months ago! Good question. Is it a polyp? The original settled polyp? Is it tha age of each polyp in a colony? The age of the whole colony? What about a fragmented colony? Acropora infill their bases and eventually "give up" on those base polyps to allow for growth of branch tips. In any event, the life expectency of a colony is theoretically unlimited. For a polyp, it depends on the species. For reproduction, it is generally the colony itself that determines readiness, although for single polyp corals it is the polyp alone. Your comment on salvaging the older part of the colony has also been addressed in papers on reproduction in fragmented corals. The older part of the colony does remain more reproductively viable, although there is a period where reproduction will not occur because of the actual breakage process - injury repair and return to stable growth occurs first.

Keith Redfield

maybe. I don't think enough experience exists with mass spawnings in captivity yet to say one way or the other.

Not to pull a harker, but tell you what I will pull up all references I can find of spawns nuking a tank, and you pull up your list of successful creation of new coral via spawn. Then we count...

;^)

My point is only that if you haven't got a system designed to anticipate this, you're going to have serious problems. Mikes plan seemed reasonable. But still lots about settlement queues, male vs female, etc not known too right? Bear in mind I've never kept those ugly brown sticks you folks call SPS.

Eric Borneman

references? I'd settle for one. You mean reports, don't you? LOL

OK, what about the reports of the plenum crashing tanks? Or power failures? Or sea apples? Or Rio powerheads? I would argue that this is aquarist lack of foresight or lack of ability in managing a tank, or currently unmanageable situations. IMO, it does not mean that you should just say, hey, spawns have the capacity to nuke a tank, so lets forget about it. A new Acropora in a tank can nuke the whole thing, too, but its not stopping anyone from keeping them - perhaps it is causing some degree of caution and foresight, and I think thats all thats required to deal with potential coral spawns, too. On the flip side, I have had several large spawns (not mass) that have not been a problem at all. Of course, thats a report, not a reference.

As for creation of coral from spawn, that is being done left and right in all sorts of recruitment studies. I could name five papers - references - from a single conference alone.

My point is only that if you haven't got a system designed to anticipate this, you're going to have serious problems. Mikes plan seemed reasonable. But still lots about settlement queues, male vs female, etc not known too right?

That's exactly right. And it appears that Andy, who started this thread, is a person trying to design a system to anticipate this without serious problems.

Settlement queues are coralline algae for all species studied thus far with a heirarchy of preference between species. It does not appear that rugoosity, light, or biofilms are involved. Perhaps depth. Male v. female obviously. For hermaphriodites, its a non-issue. For gonochoric species, it would be necessary to sex them, but for those so inclined, this is not really a big deal. I can't tell a male from female Bangaii without effort, either. Maybe not even then ;-) Those breeding them as amateurs tend to throw a whole bunch in a tank and let them figure it out. Why not the same for corals?

Richard Harker

Not to pull a harker, but tell you what I will pull up all references I can find of spawns nuking a tank, and you pull up your list of successful creation of new coral via spawn. Then we count...

I'm not quite sure what you mean by a "harker." We don't need tank references. There is a documented case where a spawn occurred during an incoming tide rather than outgoing tide and it killed off 90+% of the coral and a very high percentage of fish in a lagoon. That would tend to suggest that there is a real danger in a captive mass spawn.

Personally, I'd look at having, say, a 500 gallon system plumbed into a 500 gallon reserve. 1000 gallons total and when the spawn is anticipated, you can close a valve and have 2 separate systems that have essentially the exact same water chemistry. Then when the spawn happens, you can do a 500 gallon water change (100%). Simple if you design the system right.

Mike, it is a little more complicated than that if the goal is to "capture" the spawn (here I'm talking about a broadcast spawn). Your engineered solution may prevent a tank from going anoxic, but you still have to deal with the spawn.

Capturing the egg bundles is fairly easy if you can do so right after the spawn. They can be collected with a net, but the bundles quickly dissolve and you have large eggs and a scum (the sperm). How do you collect and save sperm?

The best solution I've seen is one where the animals ready to spawn are moved into a seperate system, where they are allowed to spawn and then removed. You now have a system with just egg bundles. If you have other corals spawning at the same time, those bundls are mixed with the original batch for cross fertilization.

Hundreds of gallons are used for a small spawn and large water changes follow any successful fertilization.

The process is fairly simple, but labor intensive. Probably not the sort of thing a hobbyist with an aquascaped system is going to want to do.

James Wiseman

Do you think it would be possible to capture eggs and sperm from the slick out at the flower gardens and settle the fertilized gametes onto Tampa Bay Saltwater or some other Gulf of Mexico liverock?

I ask because I am going out on a "research" trip with NOAA during the spawn this year, and weather permitting, I should be able to capture some gametes. If so, how long do I have to settle them? Would I have to settle them offshore in holding containers, or would I have say 36 hours to get back to dry land and settle them at home?

I think it would be a fun thing to try, but I only have 3-4 weeks to get ready.

Richard Harker

I think it would be great to try to capture a spawn. Last year I photographed the mass spawning on Bonaire for several nights and the literature I've read on the flower garden spawn suggests that the spawn is very similar.

All you have to do is find a coral ready to spawn and place a garbage bag over it. The buoyancy of the egg bundles will cause them to float up into the bag. You'll quickly get several hundred egg bundles.

I'll have to review the papers to tell you how long before settlement. As I recall, something like 24-72 hours, but let me check.

I've been monitoring mass spawning in the Solomon Islands for the past five years, and there the egg bundles break down by the following morning producing long slicks. In 36 hours you'll have a few fertilized eggs, but mostly die-off. The key to keeping the fertilized eggs alive will be to dilute the water as quickly as you can.

I've got both video and stills of last year's spawn. Let me know if it would be helpful to send you copies.

There are literally hundreds of articles that would fall under the header of 'spawning', but do not appear in the databases under this moniker due to the fact that the research is much narrower and focuses on only one small aspect of the greater topic 'spawning'.

Actually there are relatively few references regarding stony coral broadcast spawning and therefore a short list for Andy to review. There's one article on the Texas flower garden mass spawn, two on the ABC Island mass spawning and a handful of Indo-Pacific references, most regarding the GBR.

The GBR seems to be the most predictable. There's a large flotilla of dive boats that go out to watch the spawn over a couple of nights. The most spectacular mass spawning I photographed was on the GBR. Other areas are not as predictable.

Creating a captive mass spawn (as opposed to a single coral going off) would depend on having a number of corals from the same area that behave similarly. In a typical tank with corals from all over, one going off wouldn't necessarily create a mass event.

One other note. In my experience, the largest corals are not necessarily the corals that spawn. I've observed tank size corals spawning while nearby much larger corals failed to join in.

James Wiseman

My company is sponsoring this trip (or part of it) for the FGBNMS ppl, and others from NOAA, NMFS, MMS, you name it. I will be out there _hopefully_ for the spawn, but I don't know if I will be able to devote a dive solely to capturing gametes/zygotes. I may.

My preferred technique would be to collect the gametes as they float up in the late night/early morning. I would hope that they would be viable at this point, and I think there is a high probability that they will be fertilized. I can set up a holding tank on the boat, and add a predetermined amount of gametes to the tank, as opposed to taking gametes OUT of a closed system. I may also want to sieve the gametes and set up different systems w/ the larger and smaller ones...

If I can get them settled, I think I can keep the "cultures" alive until I get back to shore (~36 hrs) and into a slightly more stable environment. I will be looking forward to any help you and others on the list can provide.

Private aside I would certainly like any feedback you can provide, having "been out there" I have never dove during a spawn. Literally any information will be good information. To complicate matters, the Flower Gardens are deep dives, _cresting_ at ~65 feet.

Mike Kirda

My original answer addressed the concerns othered voiced on the advisability of having a tank spawn. Certainly the bulk of the reports cite fish deaths, some have coral death, very few show a complete tank 'nuke'. The key is being ready for the spawn and being able to perform the water change(s) needed to keep the tank alive.

Now, capturing spawn for fun or profit, that is a whole other matter. And a relatively simple one at that...

First off, you have to have a male and female of the same species, or at least a very similar species- there are reports of hybridization.

Once you are relatively sure that a spawn is coming, you should dust off that old college-era beer bong. If you don't have one, then you should make one- a simple funnel and tubing will do. Choose tubing that will match the size of the funnel's smaller end.

Once the coral's start to spawn, place the large end of the funnel over the coral and start the syphon into a 5 gallon bucket. Do use a separate one for the eggs and sperm...

My best guess is that these can remain untended for 30 minutes to an hour. Work on doing your water change...

Come back to the buckets. You will need to do a good guess as to density- you will want to introduce spermegg in a 1:1 ratio. Do so and mix gently. How you do this is up to you- I doubt a powerhead will be suitable...

What you do next- and have to do next- is pretty much uncharted ground. I am certain that you can get viable spat, and they should settle on coralline algae. Some coralline that has been ground and added to the vessel might help induce settlement. Beyond that, you will need to read up on every spawning/settlement/spat article that you can lay your hands on.

Created by liquid
Reefs.org
Last modified 2006-11-24 18:40
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