Maxea clam, is there such a thing?

skinz78 · Feb 11, 2011

OK this post is just my beliefs and my own personal thoughts. There is nothing scientific behind these thoughts or beliefs. Until I see scientific proof that there is such thing as a Maxima / Crocea Hybrid this will remain my belief.

I have had many many clams over the years, every obtainable Tridacnid, and even a few Hippopus's. Most of the clams I have had were either Crocea's or Maxima's because of their slower growth rate and size.

I purchased a "Maxea" that was about 3"

Frontal view, disregard the Squamosa in the background.

Top down view.

Side view.

Bottom view with byssal opening.

Notice the scutes on the sides of the clams shell, now remember that the Crocea clam is also called the "rock boring clam". In the wild they are found burrowed deeply into rocks so that just the mantle is sticking out. In doing this they rub all the scutes off. Furthermore most of the Crocea clams that we receive in the home aquarium industry are wild collected. The Crocea isn't farmed nearly as much as the other Tridacnid clams just for the simple fact of their slow growth rate. If a clam is slow to develop then the farmer isn't making as much money on that clam.

skinz78 · Feb 11, 2011

Now it is time for my Crocea's.

The first one is just a plain old blue Crocea and is almost 5".

Side view.

Bottom view with byssal opening.

Now this is another plain old blue Crocea, approx 3".

Side view.

Bottom view with byssal opening.

And my fourth Crocea, this guy has set himself into place and after the stress it just went through I am not gonna cut it's treads and take pic's so one frontal through the glass is all you get. It spent over 48 hrs in shipping thanks to Fed Ex. Clam is approx 4" and has been in captivity and not boring into rocks for approx 2 yrs to my knowledge. You'll notice the scutes formed on the shell, pardon the bubble algae, we're working on that.

skinz78 · Feb 11, 2011

And two of my Maxima's, both about the same size.

Side view approx 2.5"

Bottom view of byssal opening, they attached to gravel sorry.

Side by side pic of the supposed "Maxea" and the 5" Crocea.

The 3" Crocea.

"Maxea".

4" Crocea.

"Maxea".

Maxima.

skinz78 · Feb 11, 2011

Now lets look at what I call the coup de grace for the fabled "Maxea". Sure you may say the side views of them shells are a lot alike but these byssal openings tell the truth to me. Notice the very pronounced teardrop shape?

"Maxea".

5" Crocea.

3" Crocea.

"Maxea".

Maxima, once again sorry for the sand.

skinz78 · Feb 11, 2011

OK for all you non beleavers out there that say well look at the mantle and it's awesome coloration. Well I have had gold Crocea's in the past and I really wish I still had them. The sad thing is that they have passed and now I only have pictures so here is a comparison of mantle coloration's.

"Maxea".

Gold Crocea.

3 Crocea's both blue and gold.

Top down of the same three in a different location in the tank.

Gold Crocea's.

So to sum this up do I believe there is such thing is a Tridacna Maxea? No. Not possible, if it were they would have done so by cross breeding out in the reefs of the world long ago.

What I think is happening here is there is a importer or clam farmer out there who is importing these supposed "Maxea's" as a way to sell farmed Crocea clams that they have believed that us American reef keepers thought to be plain because they aren't the sought after blue color. And why wouldn't they, they are making a lot of money for doing so. I paid $100 for my "Maxea". Do I think I got ripped off? No. To me I would much rather have a tank full of these non desired clams rather than blue clams. To me blue is boring. To be honest the clams that are often the latter clams to sell on the larger clam retailing websites such as Clams Direct are the clams that are the most desirable to me. Call me crazy but they are what I like.

Until I see scientific documentation showing the DNA of a Crocea / Maxea hybrid to me there is no such thing.

Now should you quit buying these supposed "Maxea's"? Heck no, I say if you like it and can afford it, buy it. Beauty is in the eye of the beholder and these clams are very nice.

Russellaqua · Apr 9, 2012

I've actually read an argument that Maxeas exist based on color. That argument is probably invalid. If we look at another animal that derives most of its' energy from photosynthetic organisms living within its' tissues, Acropora millepora, we realize it's the color of the organisms living within the host that gives the color. These are also farm-raised animals. We're dealing with a relatively small population with the potential for inbreeding. Any unusual genetic characteristics are magnified in situations like this. There are supposed characteristics found in the shells of deceased individuals that point to a hybrid animal. It was also argued that a genetic analysis would be too expensive to perform to prove that hybridization had taken place. One could argue that the valves of deceased individuals could be given to someone at the university level who specializes in Tridacnid clams. People like this will often perform analyses for a fee, and it's not usually a huge one. After measurement of the control groups (individuals from both T. maxima and T. crocea) and the hybrid group a statistical analysis should resolve the issue. I agree that these clams are beautiful creatures and that if people want one by all means have one. I'm just not entirely sold on the idea that they're hybrids. Variability within a species can account for a lot.

swannyson7 · Apr 10, 2012

Interesting read Chris! After seeing the pictures comparing your "maxea" with othe Croceas raised in captivity, I don't see any evidence to suggest a hybrid. As your pointed out above, the scutes won't break off if the clam isn't boring into the rockwork and the byssal opening looks like that of a Crocea. I've seen several different colorations in Tridacna crocea over the years, so I doubt that the coloration argument is valid one. Sounds like nothing more than a marketing ploy IMO.

Calvertbill · Apr 10, 2012

How do I identify my clam? It's about 28-30" wide.
http://98.218.41.235:1024/img/main.cgi?next_file=main.htm

skinz78 · Apr 10, 2012

Calvertbill said:
How do I identify my clam? It's about 28-30" wide.
http://98.218.41.235:1024/img/main.cgi?next_file=main.htm

It is a Gigas and a very nice one at that, LOL I can sit for hours watching that video stream... It looks like you have some nice Tangs in there too!

Here is a ID thread for clams:
https://www.reef2reef.com/forums/clams/57883-giant-clam-id-feeding-nutrition-pyramidellid.html

Shauno · Apr 14, 2012

Skinz78-

Nice read here and some very good points made. I agree- regardless of the genetic make up of these "maxea" clams, they are beautiful and enjoyed in our reef tanks.

Mustbenuts · Oct 26, 2014

Here's my small contribution to the debate; here in Yap I believe T.Maxima & T.Crocea & T.Noae are interbreeding on the reef and it is extremely difficult to identify some specimens with 100% clarity. Even Colette Wabnitz, expert from SPC (New-Caledonia) had problems with this and to get more information she took some DNA samples back to Noumea and will publish a report on this.
I have shown her a clam which looked like a Crocea when viewed from the top or bottom (byssus), it looked like a Maxima when viewed from the side but it had a 'teardrop' mantle which theoretically only T.Noae has; so what species was that clam, have no idea. FYI, I was the first one to farm large numbers of T.Crocea in 1988 as manager of Reefarm in Cairns, Australia.
But now here in Yap, Micronesia, I really have big problems separating the species, and I'm not the only one!

Rjramos · Oct 26, 2014

Great read! Love the clams!

sirreal · Feb 9, 2015

Mustbenuts. I look forward to reading Colette Wabnitz report about this. If you have any more info about this I would like to hear it. great post

skinz78 · Feb 9, 2015

Mustbenuts said:
Here's my small contribution to the debate; here in Yap I believe T.Maxima & T.Crocea & T.Noae are interbreeding on the reef and it is extremely difficult to identify some specimens with 100% clarity. Even Colette Wabnitz, expert from SPC (New-Caledonia) had problems with this and to get more information she took some DNA samples back to Noumea and will publish a report on this.
I have shown her a clam which looked like a Crocea when viewed from the top or bottom (byssus), it looked like a Maxima when viewed from the side but it had a 'teardrop' mantle which theoretically only T.Noae has; so what species was that clam, have no idea. FYI, I was the first one to farm large numbers of T.Crocea in 1988 as manager of Reefarm in Cairns, Australia.
But now here in Yap, Micronesia, I really have big problems separating the species, and I'm not the only one!

I'm sorry I missed your post.

I'd love to see some pictures of the clams that you are farming and maybe a thread on your clam farm?

Mustbenuts · Feb 9, 2015

Some pictures of the brood-stock I was using in Yap can still be seen in the gallery page of my website (Giant Clams from Paradise =Lagoon-clams for sea-food. - ABOUT US & CLAMS), but as for the hatchery, I have lost the lot in a hostile take-over by my local partner just one month ago. I am now back in Australia trying to plan a new project, but it won't be anywhere in the Pacific anymore, you can't trust anybody there, not even the Governments. The craziest part of the story is that the 'new owners' have not the slightest idea about giant clam farming or any other aquaculture knowledge and will loose probably in only a few weeks all I had produced before; this time everybody will loose, myself, the farming communities of Yap and the those idiots that were going for the 'jackpot'. What a waste!

skinz78 · Feb 10, 2015

I'm sorry to hear that.

I have to admit that I LOVE the last sentence of your home page!

Mustbenuts · Feb 10, 2015

And yet no large scale commercial giant clam farm exists anywhere and it is extremely difficult to find investors for this business with unlimited market potential. A paradox which has baffled me for decades!