recently, I have been getting into wanting to breed joubini's octopuses, possibly selling the young'ns to LFS's. I was wondering if there was anyway to tell the gender of this species externaly or by any markings of some sort... any information is greatly appreciated.

also if anyone has done this before, do you know whats the best way to contain all the babies/eggs before they're big enough on their own? I've heard of people relocating the eggs to other containers and tanks to be by themselves until theyre big enough not to be sucked into a skimmer or filter...

Sexing octopus is hard. Impossible in juveniles. In maturing and mature males they may have a modified are called the hectocotylus, it can be quite elaborate or as simple as enlarged suckers. I think in Joubini they have a groove leading to a cup like structure on the tip of the arm (we don't get this species so I'm dredging from longterm storage in my memory!!!).

As for holding the juvs, net breeders, critter keepers and the like have all been used to hold the juvs. Don't move the eggs, if possible leave them with mum as she'll look after them the best.

J

There are two of us that have posted journals about raising Mercatoris babies this year see the following posts for our experience and handling:

Lev in Canada:
http://www.tonmo.com/forums/showthread.php?t=8701

Trapper and her babies (mine):
http://www.tonmo.com/forums/showthread.php?t=8349
http://www.tonmo.com/forums/showthread.php?t=10133

A sure-fire way to ID a male is to find the hectocotylus (the third right arm). There's a small diagram in this thread (scroll down) that may help identify what to look for.

http://www.tonmo.com/forums/showthread.php?t=2033

I'm not sure about joubini, but in bocki (reaches similar size), you can see the hectocotylus in males with a mantle length less than 1cm.

Check out this ebay auction. Someone is selling a mated octopus pair. It still hasn't had any bids yet which is very surprising.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=66788&item=180147510206

Only reason you would want a mated pair of octopuses is to raise their young (if the female really is fertile and still hasn't laid eggs), and raising is difficult.

Here are some photographs of the hectocotylized arm as seen in [I]Enteroctopus dofleini[I]. The first two show where the suckers stop and the groove begins and the last, albeit a little blurry, shows how long it is. The arms were approximatel .5 m long. The groove is approximately 12 cm long.

Hope that helps. Of course, it is much easier to see on a 15 kg animal.

Greg