Opistignathos rosenblattii Sexing Project

So in 2007 and 2008 I saved out all the big Blue Spotted Jawfish images I could get my hands on from www.LiveAquaria.com , specifically the Diver's Den WYSIWYG images.  The premise was simple - if I could get a large enough sample size, I could conceivably search for sexual dimorphism and sexual dichromatism.  Since they take pretty good "profile" shots of their fish, I thought it's very conceivable to take measurements of the head vs. the entire body to see if there's any truth to that dimorphic trait. It's tough when you're looking at one Blue Spotted Jawfish at a time, but when you can see dozens side by side, you should have a better chance seeing the differences.
 
In the end, I had 49 images set aside!  Kevin Kohen / LiveAquaria granted permission to share their watermarked images here, so credit where credit is due, these are all from the Diver's Den at www.LiveAquaria.com.  These images are only redisplayed here for the purposes of this project and may only be used for the educational purposes of this project!  Thanks Kevin & LiveAquaria.com!
 
With 49 fish, you assume that there will be some of each sex in this sample.  If sexual allocations are 1:1, then there should be roughly half female, half male.  Of course, that may not be the case...for example if males are larger, and thus more desirable, this could be heavily skewed towards the male gender!

Here's what we do know.  #1.  Certain times of the year Males will undergo a dramatic coloration change during courtship.  #2.  Supposedly, the male head is larger / bigger specifically so there's more room for mouthbrooding eggs.  #3.  Due to #2, some diagrams of generic jawfish have shown significant differences in the actual proportions / structure of the jaws - in these examples, things like the shape and length of the maxillaries differed substantially between the male and female fish.
 
So...I've posted up THUMBNAILS of all 49 images in this post.  In addition, the FULL RESOLUTION images are available in a .zip file - download here -> http://www.cichlidrecipe....ignals_liveaquaria.zip .  If we need to discuss any particular image in greater detail, the larger originals are already on my server and can easily be linked into for display here.  However, I didn't want to put all 49 full size images in the thread (it would've been a 4 mb download!)
 
So please work with this dataset and see what you can come up with!  Certainly, if you're going to measure pictures, some may not be valid.  Also note, if an image shows 2 fish, it's an image of the same fish on each side....NOT a pair.
 
Thumbnails to follow.
 
 
 
 
 
 
 

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Thanks Matt.  Can't download the pics at work, but I'll review later tonight at home.

Rook

Matt, do think any pics of known males or known females would be helpful?

If it helps, here's a video of my male in courtship dress:
 
http://www.youtube.com/watch?v=U9drg-pcPvM

--Andy, the bucket man.
"Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886

Mike, absolutely.  If anyone has extra pictures (especially if you know the sex) please post them up.

Rook

Andy, did you have a pair, male and female?  If so, want to post up some pictures of the male and female, and offer your thoughts on sexing them?

Rook

I tried on three or four occasions to pair him up. That once was the only time he ever seemed interested, so my assumption is that was the only time I found him a female _or_ that was the only time I found him a female after he was of age/readiness/time of year to court.
 
I never saw him show any signs of caring about the others (but it's a big tank) other than just petty squabbles. Oddly enough, despite the fact that it's a 28 square foot tank, at one point I had 6 jawfish (two bluespots, four pearlies) living within the same square foot. The pearlies gave me a few batches of eggs.
 
I will go and look for photos dated around the same time as the video. My initial feel for it was just entirely random chance and this guy never helped much. He just never acted like he cared that much that any other fish was around.
 
It's easy to tell him in photos, though. He had a cave-in accident at the LFS and had a broken jaw that mended crooked.

--Andy, the bucket man.
"Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886

Here's another video of the same jawfish:
 
http://www.youtube.com/watch?v=DuDf_D6I7dg&feature=related
 
I've found one photo of him around that time, and none of the female. In my defense, that was when I was desperately trying to raise some seahorse babies.

--Andy, the bucket man.
"Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886

That should be a helpful video.  Only males exhibit the mating colors, right?  So we are pretty confident that the jaw in that video is a male.

Rook

Here is a nice video but no idea of sex. http://www.youtube.com/watch?v=Tmcr1EtLcjc&NR=1
 

http://www.fishtalpropagations.com/#!home/mainPage
"Making captive breeding easier."

And heck, that guy is still alive. He doesn't leave his hole very often, but I can get some more photos.

--Andy, the bucket man.
"Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886

Okay. This is a known male. Remember that his jaw is a little screwed up.
 

--Andy, the bucket man.
"Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886

Andy, 
 
Does he seem to always have that darker, more golden yellow color and more gray body color?  If you look at Matt's pictures (keeping in mind lighting) there are several that are clearly darker and more golden and others that are clearly lighter and more light yellow.

Rook

Andy, a full body shot, similar in the layout to all those other fish, would be EXTREMELY helpful.  That way people could take proportional measurements and start making comparisons and looking at an overall dataset.

Okay, I went back through a bunch of old photos and found some things for you:
 
Here are a few shots of Oscar, my known male:
 

 

 

 
 
And here is a series of photos of second, probably male, bluespot in an agonistic encounter with Oscar. Oscar is the fish that comes in and steals this fish's home:
 

 

 

 

 

 
As you can see, the fighting, territorial defense colors get very close to the courtship colors.
 
I hope that helps.

--Andy, the bucket man.
"Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886

Here is a video of my bluespot.  Sex is unknown, however I'm suspecting a male.  Just a very early guess based on the dark coloration and the extra flaps of skin under his jam (supposedly for extra room for babies?)
 
Hope it works, its my first attempt with youtube
 
 
http://www.youtube.com/watch?v=hIPgGObsTvU

Rook

I've just been flipping through the downloaded pictures and I'm not sure I can find a clear distinguishing feature.  Color seems hard to tell since the lighting and the fact that they can change color makes it unpredictable.  I'm not sure I see a difference in head size.  Some do seem to have a darker area behind the eyes.  I'm trying to see if some have more excess skin under the jaw area, but most of these pictures don't show that.
 
 
So, how hard is it to get a blue spot out of a tank if the two are the same sex?
 
 

Rook

It depends on your tank. My fish store does it all the time. I doubt I'd be able to get mine out, though.

--Andy, the bucket man.
"Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886

Made it out to the LFS, unfortunately they only had one bluespot in stock, so it was not much help.  Looking back at Sissy's video, her male and female look identical (though you can only see the heads).  I wonder if adding a bluespot in a enclosed net container or critter container will cause the bluespot that I currently have to react enough to see the color changes?
 
Is it just the males that are supposed to change colors in defense of their homes?

Rook

The problem is that I don't know if anyone knows. They were/are so expensive and such delicate fish (lots of deaths right out of the fish store) for so long. On top of that, they are so hard to pair. It's only a small subset of the hobby that would try to keep these fish and a much smaller subset that would even try to pair them. There's just not much data to go on. I think this is a great project though, because if we _can_ figure something out, it'll be a great boon later on.

--Andy, the bucket man.
"Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886

I'm going to try and see if I can snag a few of them, and get the LFS to let me return the all buy one after I'm done trying to sex them (heck, may be able to sex several them and thus help them sell some, or sell some pairs).
 
I'm going to try and rig up some fully enclosed net "cage" like a breeders net but with a top on it that I can  sink into the tank, but yet be able to pull back out easily.  I don't think I'd be able to get a blue spot out of my tank with out tearing it a part.
 
I'm picking up some used tanks tonight to start working on a basement setup.  Not sure how quickly I can get it going though.  (I'd like to clean the basement work room and put down some epoxy on the floor first, but that's on a long honey-do list).
 
 

Rook

Do not be afraid to VENT them.  Take macro shots of the ventral surface, specifically the anus and genital openings.  This is how MANY freshwater fish can be reliably sexed.

How do you do that?  Lots of patience with the camera?  Or take them out of the water?

Rook

Here is a video of a male / female bluespot spawning.
 

 
 

Rook

Another from the same pair. 
 

Rook

mama from the same pair.  Short, but a good look.  Quite swollen, bit out of focus.
 

Rook

Mama again.  I think she is still swollen, but note that she does not seem to have the extra flaps under the jaw (though again out of focus a bit).
 

Rook

I don't know, Jeremy. She looks like she has the extra flaps to me.

--Andy, the bucket man.
"Not to know the mandolin is to argue oneself unknown...." --Clara Lanza, 1886