We got babies!!!!!!

Discussion in 'Octopus Care' started by Jean, Feb 6, 2003.

  1. Jean

    Jean Colossal Squid Supporter

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    Over the space of a few days at our public aquarium (where I work part-time!) we've had several hundred baby midget octopus hatch (Octopus huttoni) This is the first time in over 30 years. We're planning on releasing a lot of them (it's a small aquarium & we have no space to try raising so many!!) but we will be keeping around 300 or so.

    We've set up a culture of brine shrimp which we will be feeding to them (only the newly hatched nauplii tho!) anything else we should be trying? These babies are around 3-4 mm total length and we know from experience that the adults just won't be trained to take dead prey so we're fairly certain the babies won't either.

    Any advice will be gratefuly recieved

    J
     
  2. Colin

    Colin Colossal Squid Supporter

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    Hi Jean

    LOL you got me reaching for the books and mouse there!!!!!

    As far as my books go I can only find one reference to that species and it is a book called 'The marine fauna of New Zealand: Octopoda (Mollusca:Cepalopoda) which is written by some guy called O'Shea or something like that.... :twisted:

    I also found that it used to be called Robsonella huttoni.....

    Apart from that not much else and nothing as far as husbandry is concerned. However at 3-4mm they are small paralarvae ans will need small foods..... it is well documented that Artemia nauplii are unsuitable as a first food for cephs so many suggest the larvae or crabs and other shrimps.

    Try reading this for moe info.. its the best i can find....... :)


    http://www.jimbolouislabs.com/eggjournal.htm
    http://www.cephbase.utmb.edu/refdb/pdf/6300.pdf

    good luck!

    Colin
     
  3. Jean

    Jean Colossal Squid Supporter

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    did wonder about the artemia but it was what we could get at short notice!!!

    We've had the plankton nets out so we'll suppliment with crab zoea etc. Still got many alive one week later!!!!

    Cheers

    Jean
     
  4. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    I've just copied this post from another thread here called 'rearing octopus'. I would not have thought the Artemia would have been of any use, and would have, as Colin suggested, procured crab/shrimp larvae; I'm pleasantly surprised you still have many left alive - have you seen them attack and actually consume the Artemia? Do they still have residual yolk reserves? Please post notes on progress.

    Jean, I'd be interested to know what sort of tank you were using (material, dimensions, volume, shape, colour), lighting, circulation pattern, flow rate etc, even if everything goes belly up. This sort of information is just as important as information on successful tank setups; I wouldn't have used Artemia, but there's more to this than food type (we'll be keeping larval octopus live soon).
    Thanks

    See below (repeat posting)

    Itami, K.; Izawa, Y.; Maeda, S.; Nakai, K. 1963: Notes on the laboratory culture of the octopus larvae. Bulletin of the Japanese Society of Scientific Fisheries, 29(6).

    Abstract (slightly abridged; I've left the English as it was given it's largely a quotation).

    The larvae of the Japanese commercial octopod, Octopus vulgaris, were successfully reared from the swimming larvae just after hatching to the benthic young octopus in 33 to 40 days on a diet of the zoea larvae of the shrimp, Palaemon serrifer. The rearing experiments were carried out at the Hyogo Prefectural Fisheries Experimental Station from June to September, 1962. At the start of the experiments 200 individuals of the octopus larvae were kept in a glass vessel containing about 8 litres of sea-water. During the early 20 days period the sea-water of each vessel was aerated and renewed every 3rd or 4th day, and after this period the method was changed for the use of running water. The results obtained are summarised as follows:
    1) From just after hatching, the larvae of the octopus were fed on the larvae of Palaemon of 2 to 4 mm body length. After transforming into benthic stage, they were given a small piece of ovaries, testes and hepatic glands of the crab, Charybdis japonica. Three or four days after transforming, they were fed on small shrimps and young crabs, Gaetice depressus of 5 to 7 mm carapace width. It was observed that the young octopus of 30 mm total length ate 4 or 5 young crabs in a day.
    2) The survival rate of the octopus larvae was found as low as 9 percent through the free-swimming stage. However, it would be conceivably possible to raise this survival rate much higher if sufficient food supply is secured during the rearing experiments.
    3) It was found that the larvae settled on the bottom 33 to 40 days after hatching, when they attained a size ranging 10~15mm in total length (3.8~5.7 mm in body length). Once the swimming larvae transformed into the benthic young octopus, they became nocturnal and fed on foods mainly at night. A considerable mortality occurred among the young octopus, which was caused by cannibalism and creeping out of the rearing water.
    4) The numbers of suckers found on each arm were 3 at hatching, 5 (4~6) at 10 days, 9 (6~12) at 20 days, 19 (16~22) at 30 days, 24 (21~27) at 40 days and 22~23 when a majority of octopus larvae grew to the benthic stage.
    .............
    Cheers
    O
     
  5. Jean

    Jean Colossal Squid Supporter

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    Update as requested!!! We have actually released all of the babies!!! Mainly because looking after them was way too time consuming (most of our aquarium staff are part-time grad students who are supposed to be producing a thesis thingy!) we actually only have one full time aquarist!

    Anyhow at the end of a couple of weeks we still had a hundred or so. And yes we were still feeding newly hatched Artemia, but it was suplimented with crab zoea, small mysids and small amphipods that we collected from our local harbour. The babies would strike at and catch the Artemia but as you say not much nutrition in them. They didn't seem to show any preference for any food and would strike at anything of a suitable size that moved!

    We couldn't see any residual yolk (even under microscope).

    Tanks set up was very primitive!!! we weren't expecting them and had we kept them we would have had to get our workshop technician to make up something more approprate.

    Basically we had them in rectangular plastic (~10L) tank, stocking density around 50-100 per tank with a layer of medium grained sand as a substrate no shelters as the bahaviour of the little guys suggests that they're planktonic. This was probably too many to a tank as I did note some cannibalism.

    The tanks had rounded corners and were sitting in a much larger opaque tank which has an opaque lid. we kept them in the dark as we noticed that they always congregated at the darkest end of the tank and they seemed to get very agitated whenever anyone walked past (rapid colour change and occasional inking).

    They were fed to excess 2 or 3 times a day, and any debris removed in the morning. Water flow wasn't actually measured when the water was running as the system tends to be rather turbulent, input was kept to a trickle and water changes were done once a day. I rather suspect that if we had kept them they would all have gone belly up, certainly we were losing alot every day.

    If only they had arrived when our new grad students were looking for a dissertation project!

    J
     

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