Captive nautilus buoyancy issues

Discussion in 'Physiology and Biology' started by phOOey, Apr 29, 2015.

  1. phOOey

    phOOey Larval Mass Registered

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    Hi all,

    I was hoping someone may be able to help me with some nautilus I have in my lab at the moment. They seem to have lost the ability to control their buoyancy, they all just tend to float at the surface. Other than that they seem absolutely fine health wise.

    From reading around it seems that this is quite a common issue in captive nautilus, however I have not seen any potential solutions other than a "wait and see approach". I've had them for around 5 weeks now and they are still having buoyancy issues, so I was wondering if anyone had any experience with nautilus and perhaps had a solution or treatment that I could try?

    At first I thought that the tank might be a bit shallow, its a rectangular cuboid and is only around 70cm deep, could a lack a vertical swimming space be an issue for them?

    Any help would be appreciated.
     
  2. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    @gjbarord and @robyn are the experts (@cuttlegirl also worked with them at the Hawaii aquarium) and I have only kept one but I'll pass on what I learned and hope one of the others will add/correct my comments.

    Communicating with other keepers, it seems that airplane flights (low pressure) may have something to do with the buoyancy problems almost always experienced with newly arriving animals. The best explanation seems to be the loss of some of the spicule fluid. My animal did not regain neutral buoyancy until it had grown about half an inch of new shell. I suspect that new shell growth includes creating new fluid so am guessing the two are related. It took almost 2 months (Sept 9 - Oct 7) for Zilch to achieve full neutral buoyancy (in a 3' tank kept at 65 degrees F). Greg has new nauts in the lab that were floating so he may additional input on his current wards. I don't know if the shallow depth has an effect.
     
  3. phOOey

    phOOey Larval Mass Registered

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    Thanks for the reply and information. Thats an interesting idea, I've never considered how the pressure difference experienced on planes would affect buoyancy, but it certainly makes sense that it would!

    As of now, of the 5 I have, one seems to have regained control of its buoyancy. It is the smallest of the 5. I'm not sure on the growth rates of Nautilus, but if they grow at a quicker rate early on in their lives then perhaps the smallest one has grown relatively more than the others, and your theory on growth and the production of the spicule fluid is correct. Hopefully the others will soon follow suit!
     
  4. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    The plane and fluid thoughts are personal extractions from some reading and may be off base. From personal communications with researchers, the plane part seems to hold true through anecdotal observation (the why is my guessing). The new chamber thought is a guess again but from reading about how the new chamber growth has been observed. A really great book by Peter Ward, In Search of Nautilus (out of print but available used) is well worth reading to provide some layman's insight to research on how they grow and what has been learned about them in the wild with a few hints on keeping them. I just reread the book this week and highly recommend it. It may not be so much that new fluid is created but more that the new chambers start full of fluid and slowly drain to the point where neutral buoyancy is achieved. If fluid is lost during flight, the new chamber may compensate but they did find that fluid can be slowly added back to existing chambers. Toward the end of the book, he goes into a bit of detail on the experiments they did with detecting fluid levels under varying situations.
     
  5. gjbarord

    gjbarord Sepia elegans Staff Member Moderator

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    Hello @phOOey ,

    It's definitely an area that we do not know much about which is frustrating. Some come in fine. Others do not. Some fix the buoyancy issue quickly. Others do not. I would imagine that it has more to do with the stage of the growth process of each individual nautilus when shipped than anything else. I'm sure some stress might impact it as well...

    Not sure where you're at or what resources you have, but if you're interested in looking at this further, feel free to email me at gjbarord@gmail.com. It's an area of nautilus husbandry that we definitely need to figure out!

    Greg
     
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