A certified SCUBA diver since the age of 14, Charles has made over 300 dives in locations throughout the world including Canada, Fiji, Hawaii, Indonesia, Japan, the Marshall Islands, Palau, the Solomon Islands, the Florida Keys, Bonaire, St. Kitts and St. Maartin.

Charles has lectured at over 40 aquarium-related conferences and meetings, and published approximately 40 articles in the popular aquarium literature in the last 15 years. In addition to writing a monthly reef aquarium column for Aquarium Fish Magazine since 1997, he has co-authored two popular aquarium books with Julian Sprung, The Reef Aquarium published in 1994 and The Reef Aquarium volume 2 published in 1997.

Can you tell us about the coral spawning events at the Waikiki aquarium Mr. Delbeek? When do they occur? What corals spawn? How do you manage it?

Okay ... well we have had a number of spawnings over the year here ... over the years I have been here I mean ... and before I came I can honestly say that we do nothing to stimulate or promote these events ... some of the events occur in our outdoor tanks ... and some of them occur in the indoor exhibits but ALL of the exhibits get natural sunlight and we do nothing to control temperatures ... we also get natural moonlight so we naturally have occuring the three main cues I feel that corals and other marine organisms use to time their spawnings ... changes in photoperiod, changes in temperature and moonlight phases ... I will also add that we do not directlty feed any of our corals ... but the water we use is high in inorganic nutrients such as nitrogen and phosphorous ... so they may be getting all they need from this ... okay to list them here is what we have spawning at various times of the year, though most are in the spring and early summer ... a few have been in the fall.

1. Montipora captitata
2. Acropora youngi
3. Euphyllia ancora
4. Sandalolitha robusta
5. Goniopora
6. Psammacora
7. Rumphella
8. Xenia
9. Fungia

and thats about all I can remember right now.

I understand that all of the tanks except the outdoor exibit use filtered well water. What distinguishes these tanks from the ocean? Are there any differences that might cause the corals to "behave" differently RE Spawning? Do the corals spawn at exactly the same time as the corals "next door" on the actual reef?

there are two outdoor exhibits ... one local Hawaiian reef where the Montipora is ... it gets natural seawater plus some well-water ... and an south pacific coral exhibit of about 1300 gallons that gets only well-water ... other than the water source ... nothing much is different except volume and depth :-)  the Montipora capitata spawns exactly the same time as the wild colonies in the area where it was collected ... all the other corals do not occur in Hawaii .. some are still on Palau time and some have switched to Hawaiian time. 

have u attempted to "farm" the spawn?

We have taken a stab at the Montipora and the Acropora and the Sandalolitha.  The problems are different for each ...

How do you settle the coral larvae??

In the cas of the Montipora ... we could not get them to settle out ... I don't think anyone has ... The Acropora .. only one colony spawned and they do not self-fertilize ... and the Sandalolitha is gonichoristic ... so you need both a male and female colony to spawn and the last few years only the female has ... though it did a very strange thing a few years ago ... it released SPERM one year ... since then it has released only eggs again ... its not supposed to be able to change sexes like that! coral need a cue in order to settle out ... for most Acropora it appears to be coralline algae ... for some other genera it is bacterial growth on the substratum ... for others we don't know what it is.

do you know what the max temp is that is reached in these tanks and for how long it stays there?

The max temp for the Hawaiian exhibit is about 80 but we try to keep it from getting any higher ... Hawaiian reefs don't go much above 80 naturally in the summer ... as for the indoor exhibits they reach a max of about 82-84 oF We never measure the coral farm tanks ... but they can get as high as 84 and as low as 68-70 in the winter at night. 

Do all the outdoor tanks have surges on them? If not, did spawnings occur in those systems that do NOT have surges?

The Edge of the Reef (EOR) exhibit has a no real surge ... there is one at the upper pool but where the Montipora is there is none ... it is a lagoonal coral here in Hawaii ... The Coral Farm exhibit has a 250 gallon surge device plus a constant horizontal water flow and air stones for added turbulence. The inside tanks where spawning has occured have no surge devices. 

Are spawning events something we should strive for in home aquariums?

I was on a French board this past week answering questions as a guest and someone there pointed out that spawning in a tank is dangerous ... there is no doubt that there are several chemicals released and also a massive spawn can drop O2 levels drastically ... however, in our systems, we don;t have much of a problem with this since they are open system so I just crank up the water flow ... in a closed system its a different story ... and you need to be prepared to either do massive water changes or put on a whack of acitvated carbon and drop in some additional airstones ... a massive spawn can wipe out an entire tank very quickly ... usually what researches do is take cuttings and inspect the calyces for sperm/egg bundles and this allows them to determine how close a colony is to spawning ... at which point they can then remove the coral and let it spawn in a bucket. keep in mind that most hobbyists have either a) colonies that are too small or b) too young to spawn, its usually the lower/older polyps in an Acropora colony that spawn. 

Have any of the corals at the aquarium been obtained from cuttings from hobbiests? Have these spawned?

We have a few pieces from hobbyists the most famous of which is the "Stuber" acropora ... none of these hobbyist pieces have spawned, most are too small.

Since age of the colony has been mentioned... Is it (or do you) currently believe that cuttings start the reproductive clock over again?

I think it may depend on what stage the cuttings are made ... if its early then maybe since more energy would go into growth and anchoring the cutting rather than into reproduction. I don't honestly know.

what are the water parameters of the closed systems, ie, cal., alk, ph?

We have not had any spawnings inclosed systems ... out of 50 displays that have live corals only 3 are closed systems. 

What have you had spawn at the aquarium besides corals? Fish? Cephs? Etc...

bubble-tip anemones (as depicted in the Reef Aquarium vol. 2), Nautilus, four species of cuttles have laid eggs but none have been raised, and we have had a lot of fish spawn! we will be writing an article for FAMA detailing all that we have spawned and those we have raised too ... also cleaner shrimp and Harlequin Shrimp.

Do you have any systems dedicated to raising animals that spawn?

We have some tanks dedicated to larval rearing of fishes, several species of clownfish, mahi mahi, Banggai cardinals, cleaner shrimp and Harlequin shrimp.

specifically, those that generate larvae that can be captured from the tanks themselves, not wild caught.

we don't rear wild-caught larvae, a couple of species of seahorse including one never reared before ... I can't remember them all I don't have the list infront of me ... our aquaculture person prefers to work with animals never reared before such as pygmy angels and Genicanthus personatus. 

What's your experience with artificial moon light/ coral spawning? Any update on that?

I have one tank where I have an artifical moonlight .. I've seen no evidence of spawning ... remember that these tanks are at the aquarium and we go home at 5 PM ... any spawning after that time and its only by chance that we see it ... some corals like the Sandalolitha and the Entacmae anemones spawn in the morning between 7 and 8 AM. 

Would it be a bad idea then , in a home aquarium, to set up natural photoperiods and lunar cycles?

I don't think so ... just time the photoperiods so that you can see the tank when you want  I was going to work with a company that produced dimmers and timers etc for the aquarium hobby and we were going to program in sunset and sunrise times as well as moonlight and temperature date for places like Fiji and Indonesia ... so you could, theoretically ... hit one button and your tanks lighting, temp and moonlight phases would mimic say Fiji for example. the device would automatically adjust temp, photoperiod and moon phases over the entire year... all you would do is program in a time when you wanted the lights to come on.

What species of cuttlefish have laid eggs at the Aquarium?

Sepio officinalis ... Sepia pharaonis ... Sepia latimanus ... Metasepia tullbergi ... we currently have four squid on display, the 5th was a female but she died a few weeks ago :-(

Were any efforts made to raise the Metasepia babies (Those are the "flambuoyant" type aren't they?)

Well the problem with most of eggs we have had laid were that they were not fertile or did not develop properly ... we had a few hatch out but they were premature ... It seems the more generations you have ... the poorer the quality of the eggs, so the best eggs come from first generation ... the worst from 3rd and 4th generation ... only a small % actually develop to the point of hatching. 

So your Metasepia were not obtained from the wild?

no they were not ... they were tank raised ... we get them as 0.5 cm to 1.0 cm juvenlies. 

Do you currently input data into a database on the species that are reproducing in the tanks? Such as breeders registry of the like...

Yes ... all our data is on breeder's registry, we have been suppying them with data for over 10 years. problem is ... since they don't identify the source of the data you have no way of knowing what was contributed by whom ... it used to bug me that people would write articles in FAMA detailing how they tried to raise cleaner shrimp but couldn't and that no one else had either ... yet we did it over 10 years ago .. and its on the BR database.

Earlier, you mentioned age and size being critical factors in spawning events. Could you elaborate?

Most of the colonies that we have had spawn we have had in captivity for over three years, some as long as 15 years ... they all tend to be rather large ... at least the size of a basketball. 

Charles, you said the water in these systems had high nutrient levels. What is the source of the nutrients? How high is high?

The nutrients come from the well-water ... it is acidic and passes through coral rock and lava rock ... dissolving it ... I can give you some levels that I have converted from umolar to mg/L for some of them ... these are mainly inorganic nutrients ... the well-water is pretty devoid of organics ... 

• Phosphate 0.02 
• nitrate/nitrite 0.074
• ammonia 0.04
• silicate 6.12

compared to natural seawater these are high.

Does the aquarium keep a log of pictures or other information on its web site (assuming there is one) as concerns coral spawnings or reproduction?

I am not sure whether we have spawning stuff ... there is some I believe on the Montipora ... the website is www.waquarium.org

I have an 8 year old gonipora. It has now budded 8 times. What do you feel causes the coral to bud? Pictures of the budding sequence can be found at: http://richk.geekopolis.com/Goniopora.htm

I am not really sure what causes them to bud off ...it may be stress related or it could just be a constant ongoing event indicative of good conditions ... there used to be a field of Goniopora stokesi in Palau ... it was very large and consisted of budded colonies ... the area was probably several decades old ... so maybe its a natural thing to bud like that for that species ... theres a pic of that area in The Reef Aquarium volume one we have one of that species at the aquarium but its only released one or two buds over the years ... the other species we have has never budded .. it grows by splitting its head and creating new columns ... the pics of the budding Goniopora look like stokesi, we have 10 now ... come to the Waikiki Aquarium and you can see them ;-)\

At the Waikiki Aquarium they have some systems with butterflies and angel fishes. We know that is hard to keep without having them to eat or nip corals and clams. Could you give us an idea of what happens and how is the interaction between those organisms?

A lot of our tanks have native Hawaiian corals and most fish we keep don't bother them much ... its the LPS corals that tend to be nipped at most
like Lobophyllia, Turbinaria, etc with butterflyfish we prefer to get them small ... and then have them eating prepared foods before we place them in tanks
that is what we do with local butterflys like C. miliaris, C. multicinctus, C. quadrimaculatus, C. citrinellus, C. unimaculatus, C. lunula etc etc angelfish tend to be more unpredictable ... but again ... if you can get them eating well on prepared foods it lowers the risk somewhat ... that is another argument for quarantining your fish in a separate aquarium. I am currently setting up at 5500 gallon reef and we will try some of our larger angels that we have in other tanks in there and see what happens ... we have a emporator in our outdoor tank it only has bothered a leather coral

What do you feed those systems that have Gonioporas? Do you think the reason for they to live long time is the food available or something dissolved in the water? Could it be ligh or circulation? Or the combination of all the factors? What are your observations regarding those systems?

well we don't feed the corals directly at all but as I mentioned, our well-water is high in dissolved inorganic nutrients so I think that they are getting what they need from that source combined it natural sunlight and an open system ... its hard not to be successful I think ... whenever we have tried to keep Goniopora in a closed system it has gone pale and started to recede ... we place it outside in the open system tanks and it recovers ... I think the high nitrogen levels in our well-water may be the reason ... they get it from there so don't need food ... I don't buy Julians theory about bacteria at least not with the species we have kept ... I lean more towards Rob Toonen and his feeding ideas ... I think it is definitely nutrient based ... I think we need to distill and bottle our well-water and sell it ;-)

Any ideas what might cause slow tissue recession on Euphyllia ancora? Bare skeleton shows green tinge? Don't think its any of the hobby testable params.

green tinge is a sign of endolithic algae, its always there .. perhaps high nutrient levels cause it to proliferate? I would also not dismiss some sort of bacterial link
have you tried any antibiotics? as long as pH, alkalinity and calcium are okay ... I would suspect either phosphate poisoning or bacteria. if the receding is happening along the edges of the colony that faces downwards or to the side .. its lack of light. I've seen this in large colonies we have here.

What elements do you suggest to add in aour close systems? Let's say.. for SPS corals.

elemental additions are also touchy .. especially now with some people claiming they are "poisons" or not needed ... on a French site a guy did a study where he measured a variety of metals in his tank and found that many of them were several times higher than natural seawater ... he tried some massive water changes and could not lower them much .. look at www.reef-guardian.com and go to my English forum and look under I think it was the trace  element measurement is very difficult in seawater so its hard to trust some results without knowing how the tests were conducted or having a background in chemical oceanography! .,..
I understand Ron Shimek is trying to raise funds to do some trace element analysis on tank water ...should be interesting ... anyway back to the original question ... what elements should one add. ... I still think that iodine and strontium are beneficial ... however, with the common use of calcium reactors these days, strontium additions may not be necessary ... I am somewhat concerned though, that the use of calcium reactors may introduce  a greater amount of trace elements than normal since coral skeletons can concentrate some rare metals to high levels ... I guess it depends on the type of material used in the reactor ...
when you are talking micrograms ... that 1% that is not calcium carbonate can still contain a lot of other stuff I think ... I guess we will find out as tanks using them get older ... 

how can i maintain the "blue" in acroporas, is it sheer PAR or does UV have an input?

I think blue is mainly PAR but I still feel that UV plays a role ... our outdoor corals get full sunlight ... and hence full UV ... no problem ... but you have to acclimate the corals to higher UV levels SLOWLY ... so it takes some skill and equipment to do safely. 

You mentioned earlier that you do not use surge devices on your inside tanks where spawning has occurred. What do you use to provide water flow in these tanks and how important do you see overall water flow as an ingredient in a successful reef aquarium?"

It depends on a number of factors ... not the least of which is what coral you talking about ... for some good water flow is absolutely critical ... for others, adpated to lower flows less so ... in one tank that is 350 gallon that contains Goniopora, Euphyllia, Sandalolitha ...all of which have spawned in there ... I have an undergravel filter plate with a lift tube in each corner, and a LG MD3 plus a small powerhead for circulation ... so not a lot. go to http://waquarium.mic.hawaii.edu/vt/index.html , and click on the gallery one item and go to Lagoon Coral exhibit for a pic, water motion is important ... but it all depends on the type of corals you have.

thanks for a great chat Charles!