Spawning event...captured video and stills!

[artful-dodger]

Clam climax? Mollusk money shot? Bivalve booty call?

Exactly how far can I take this???

Tonight just after the main lights went off large Tridacna deresa started spewing forth large eruptions of milky white sperm from its exhalent siphon via strong contractions of the clam. This continued every 4 or 5 minutes for over an hour leading to a very cloudy tank.

At that point the pheremone level from this event triggered my T. crocea to do the same except on a faster schedule of about every 30 seconds and with more "stringy" than cloudy.

The two hobbyist books on these animals (Giant Clams by Daniel Knop and Giant Clams in the Sea and the Aquarium by James Fatherree are both rather silent on spawning other than a passing mention of behavior in the wild and possible triggering by moon phases and/or increased seasonal temperature.

My tank temp varies less than half a degree (THANK YOU, CONTROLLER!!!) around the target of 77.5F and I don't run a lunar cycle on my lights.

My calcium levels have been down (320ppm) and I've been boosting slowly over the last couple of days. Alk has been holding steady at 10 dKH. Also, my pH has been lower than I like (8.0 - 8.1). Both of these were due to a dosing pump problem that I found yesterday. (I'm going back to a Kalk drip until I can get a replacement tubing set for the pump.)

The only other recent change in the tank was having to take one of the VorTechs out of service yesterday for some warranty work.

Surprisingly, even WetWebMedia doesn't have much to say on clam spawning in the aquarium.

A number of posters in the "Tridacnid Clams and Other Mollusks" forum are pretty adamant about clam spawning being a result of stress and a sign of an imminent death. I don't know that I buy into that (other than the heavy pollution from all of this heavy discharge. However, not one to take extra chances, I've spent the evening changing out carbon and poly filters, cleaning the skimmer and doing a 50g water change as precautions. I'll do another water change tomorrow or Thursday when I get the vat refilled.

I got a ton of videos. It'll take me a while to get that edited and posted--I'll try to get some added tomorrow (assuming I'm not in evergency mode.). In the meantime, here's one still photo.

I'll also update with any further developments if the end of the world is indeed near...

 

[jaw969]

What an awesome pic!! I have a deresa as well (it is my favorite clam)

I hope yours is spawning!! Thanks for sharing

 

[Clown-N-Around]

I went to search the clams direct forums and it looks like Barry set up and independent forum. After a quick search, here is one of the posts on spawning: http://www.reefaquariumforum.com/viewtopic.php?f=1&t=752&p=6268&hilit=spawning#p6268

Pretty much all of the threads there pointed to stress as well. I had my Derasa and Crocea spawn also. I think there were temperature changes near the time of the event, but both clams lived for a long time afterward.

 

[Dave & Monica]

So if you end up with tons of little ones, sign me up on the "will buy list" - Also great still action shot.

Dave

 

[Frankenpora]

Had you done a top off of Freshwater?
I know nothing about clams. But I have been noticing increased spawning activity after water top offs. Also Anemones usually split
after a major change. In order to induce fish spawning breeders will put fish into a new environment. I may be way off and connecting dots that are far from each other, but I thought it was worth saying.
Cool stuff Dodger.

 

[artful-dodger]

The tank was still very cloudy this evening so I am in the process of doing another (60g) water change. Will probably need to do another tomorrow. This is the first time I ever found a 75 gpd water purification system to be a bit too slow!

Got a week's worth of skimmate in 24 hours.

Clams and fish all look okay...corals have been retracted all day.

(Jeremy, in answer to your question...I use an auto topoff so my SG doesn't vary.)

 

[The Grim Reefer]

Don't want to worry you but Dave (Freddy40) went through the same thing with a spawn and ended up losing all his clams after it happened.

Don't know if it was coincidence or related to the spawn. Once he went clamless for a month or so I think, he has been able to add new clams and they seem to be doing fine. He wasn't able to get any answers to what caused this but the timing seems to point to the spawn. It is possible he had a disease introduced into the tank and the spawn was a reaction to that as well, dunno.

Here a couple links to his threads

http://reefcentral.com/forums/showthread.php?s=&threadid=1345890

http://reefcentral.com/forums/showthread.php?s=&threadid=1382707

 

[artful-dodger]

Yeah, I read his posts the other night...I think that a spawn is a more likely culprit than the lighting.

I still don't buy the claim that the act of spawning weakens and kills the clams (if it did, none would ever reach maturity to produce ova) but as cloudy as the tank has been for the past 36 hours (even with two massive water changes) I can believe that the pollution could certainly kill.

 

[tkeracer619]

During clam propogation they isolate sections of clams incase they all die, which is a possibility. It in itself is dangerious to the clams, they require 300% waterchanges per 24h during this process. This is why all clam propogation is done on the beach so they can pump filtered sea water through the systems. They still suffer heavy losses on all clam spawns in these facilities. I researched this as a fun side project, unfortunatly I am having a hard time finding an ocean to pump from =D

Awesome shot! Good luck.

 

[artful-dodger]

Well, it has been two and a half weeks. Both clams are doing great...I do believe that the three large water changes within the first day was the pollution solution. As far as the "stress causes desperation spawning and then they die" theory...my experience doesn't back that up.

I'm still having some challenges in getting my Ca and Alk back in line after my dosing pump issue that (I believe) caused the original incident.

And I promised videos. I finally got got over a GB of video edited down to some more manageable chunks, but these are still at the originally captured resolution in AVI format. Consider them as broadband downloads:

T. derasa spawn (22 MB, 12 seconds)
T. derasa closeup (19 MB, 11 seconds) This one really highlights the strong contraction of the entire clam to expel its sperm.
T. derasa closeup cont'd (40MB, 23 seconds) This is a continuation of the last shot after editing out about 20 seconds of little interest. Note how the sperm continues to drift out of the outsiphon like smoke after the main contraction.
T. derasa spawn (30 MB, 17 seconds) This contraction is taken from a bit farther back, just to show the clam in its space on the tank bottom. Note that the fish show no particular interest in the fine, "smokey" sperm of this clam.
T. crocea spawn (46 MB, 26 seconds) Note the more rapid cycle of contractions in this particular T. crocea, compared to the much larger T. derasa. Note also the more "stringy" consistency and the increased feeding interest by the fish. One other apparent difference between the two clams is that sperm appears to trail after the major contraction in the T. derasa but seems to precede the T. crocea's primary expulsion.
T. crocea spawn (25 MB, 15 seconds) The item of difference that I noted in this particular clip was the interruption by the tang trying to pick some algae from the shell scutes. Even though the clam retracts from the tang's approach, the contraction and expulsion of sperm continues "on schedule" even the clam wasn't fully opened to achieve the greatest force.

 

[marc price]

obviously h20 exchanges did it, but do you think the carbon and poly filter helped remove whatever compound, protein, enzyme or other which is apparently toxic to them?
i assume you're referring to polybio marine poly pads and did you use their reactor or one similarly designed for no water bypass?

 

[artful-dodger]

I can't attribute it to any one cause...I put all possible efforts (other than ozone) in those first couple days. (It took me a week to get the ozone and ORP controller in place.)

I had polypads but I have always suspected them of being more hype than value. I used a PURA Filtration Pad that I picked up at IMAC in June. First time using it so it's impossible to separate its function from the carbon, etc.

It is a thick pad that really resists water flow--would probably work well in a drip filter but that's been gone a long time. I cut and jammed it into the sponge trap between the two chambers of my Oceanic sump and then put the sponge on top. It seemed that probably half of the flow was bypassing the pad.

 

[marc price]

poly pads aren't hype. stated using them in 1984 once i realized that chemi pure (ion exchange resin/activated carbon), was hype. no carbon should be used as long as dick boyd claimed chemi pure was effective.

i've a few ocean clear, sea clear or whatever their calling them these days and a iwaki pressure pump collecting dust and am wondering if you think the 50sq' canister filter would help? used it last to help clear the water when i added a dsb to the existing set-up. only i never heard of aragonite milky water killing anything.

i don't know what i fear more between the possibility of my sebae anemone or squamosa clam, spawn. not to concerned about my crocea's, should i be?

 

[artful-dodger]

I'm certainly no expert. I've just had the one incident and am relatively sure that it was caused by the Ca/Alk/Ph swing from the malfunctioning dosing pump setup. I can't speculate on other solutions...this isn't something I plan to run multiple experiments on! I can just report what worked for me in the hope that it might help someone else.

I started my research that evening while I waited for the clams' "pool party" to end by checking my two clam books (not much help), the RC clam forum (lots of different opinions) and www.wetwebmedia.com (not enough time to sift through all possible FAQ entries.)

People over on the "Tridacnid Clams and other Mollusks" forum will, I'm sure, have other opinions and experiences.

 

[rmougey]

I was curious how things were going... glad to hear that everything turned out OK. Chalk me up as a Poly-Bio Poly Filter believer. Did they solve the problem, probably not. But I'm sure your triage of massive environmental correction is what kept everything swimming.... er... lying.... sitting??? um... never mind.

-Rob

 

[artful-dodger]

Well, mostly they just bask...

 

[Clown-N-Around]

Glad to hear the clams and other inhabitants survived.