Raising Octopus Hatchlings Links

DWhatley

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I have joined a Google+ private group, Cephalopod Aquaculture Research Lab, studying growing octopuses for commercial use in Japan. The primary scientist for the project, Drifloon Che has been kind enough to answer some of my inquiries as to success and feeding and I am passing on his summary from last years brood. Note his comments about raising on live vs frozen.

n regards, to live feeds, we're mainly looking at amphipods and mysids, which we recently discovered can be easily shoveled and sieved out of the sands at the local beaches here provided it isn't too cold. The mysids in particular were plentiful at the transition between the sand and a rocky shoreline. Not sure if anything like this exists in the states though (I presume it does somewhere if a related species exists, try genus Archaeomysis). Hand feeding these critters to our babies last year proved successful, although we had already been keeping the babies for a couple weeks on a mix of chopped up dead whelks, mussel, and crab meat prior to the discovery by the Prof. from a local source. The dead feeds kept them alive long enough for us to establish a supply of live animals, but we found none of these feeds could sustain juveniles for sustained periods (probably two months max, with most not getting to that age). As these juveniles had already become acclimated to being fed, we just did as we always did even after switching to live food. Still, the response was definitely much stronger with live prey, and the struggling definitely provoked much more active feeding among juveniles. This year we're thinking about just releasing the 'pods into the enclosures with the octopuses, and putting some sand in to encourage the critters to stay at the bottom. Not sure if the octopuses will like the sand, but there have been reports that juveniles of other species do burrow in the sand, which would allow them to encounter the prey, unlike in the previous cases we had with pelagic mysids. Might also try polychaetes from a local tidal flat since there was a group that had success with O.bimaculoides attacking those. The tidal flat polychaetes are small, so probably suitable.
Just a note on the small egged octopuses, we did make another attempt at culturing them this year, but got nothing useful out of our efforts. I made some attempts hand feeding some juveniles with large mysids, which they accepted on occasion. Problem there is that there was simply no way I could be around enough to feed them effectively, even spending hours with them and trying to feed at least three times a day. Probably really stressed the paralarvae as well. Keeping live mysids with the paralarvae did not help as the paralarvae had extreme difficulty catching them. Also did some work with amphipods, which failed despite a promising start. We observed that some paralarvae were capable of catching and feeding on amphipods, which was confirmed by expansion of stomach and crop, after being initially raised on a very limited crab zoeae supply, but for some reason by the experiment's end the juveniles were refusing to feed on the amphipods. We suspect that bacteria carried in the amphipods may have gotten to the paralarvae. We only got slightly over two weeks this year, despite reducing the paralarvae we included in our experiments to improve the available feed per paralarva. Certainly seems that zoeae are important as the paralarvae were always seemingly full when with the zoeae, but seemed hungry the day they exhausted our stock as judged through stomach content, despite some other foods being available. Still looking into production methods...
 
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My most urgent question is should I move the eggs to a breeding area?
There are 5 other aquarium fish in the tank.

My pigmy octopus, It was sold as a brown pacific octopus.
It is very small, 8 inch arms, the body is the size of half my thumb.
In just hid away for 5 days and we discovered it under a rock with eggs hanging down from the rock.

What should I do?
There are 5 other aquarium fish in the tank.
Should i move the eggs to a separate breeding cage?
How long before the eggs hatch, if they do?
What kind of food?
What preparations should I make?
HELP!
 

DWhatley

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Is the female still alive? If so keep her with the eggs as she will care for them until they hatch. If you can remove the fish or isolate the mother and eggs in the tank, I would recommend that over trying to move the eggs. If you do move the eggs, use the water from the existing tank and try to minimize any changes to the environment. I would suggest not doing water changes while the eggs are brooding.

Roughly how large are the eggs? Rice or grape seed in size?
 
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I'd say rice size. The mother and eggs are under a rock and can not be seen. I had raised the rock once this morning looking for and expecting a dead Harley.

How can I tell if the eggs are fertilized?
Do I dare raise the rock a second time?
Should I and if so how to give the mother food?
I am rather stressed and would like to make this work.

I see three options, please tell me the one that is the best choice!
1. move the eggs and the rock into a breeding net box, in the same tank, with the mother.
2. move the eggs and the rock into a breeding net box, in the same tank, without the mother.
3. Move the fish and cleaner shrimp, I don't have a plan for this alternative, but if it is the best I'll make it work. I'll need to set up a new tank using some of this tanks water and rocks. with this alternative, how long will the mother and eggs need to have the tank to themselves?
Of course if you have any other ideas, I'm all ears.
 

robyn

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Unfortunately even if the eggs are fertilized it is not currently possible to rear these hatchlings; the very small-egged species hatch into tiny paralarval octopuses that no one knows how to feed them to keep them alive. The female may or may not survive to hatching, but in my experience (I have kept a good many of this species in my lab, and the females often lay eggs) if the eggs are fertile and at least ~14 days developed before the mother dies, they will hatch as long as there is water flow over the eggs. You will be able to tell if the eggs are fertile around day 10; you will see red eye-spots developing. I'm attaching a picture of eggs from a female of the same species in my lab at 11 dpl, just when the retinas are just starting to pigment.
You can certainly gently lift the rock to look at the eggs; it sounds like you've had the octopus for a while so I am sure she's habituated enough for you to check the eggs out. I would suggest leaving her and har eggs where they are, even with the fish in the tank. You can offer food as usual, but remove it promptly if she doesn't eat immediately. In my experience some females will continue to feed in the early stages of incubation, but all eventually stop eating. I've had a couple of females survive up to two weeks after their eggs hatched.
 

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