the impossibility of keeping squid in captivity

Discussion in 'Physiology and Biology' started by bagarius, Nov 14, 2009.

  1. bagarius

    bagarius Cuttlefish Registered

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    I saw a documentary referencing the Discovery channel special where the good Doctor Steve O'Shea caught some juvenile Architeuthis . What I don't understand is why they died... the video said that they did fine in cylindrical tanks, but as soon as they were put in a rectangular tank, they sank to the bottom, went belly up and died. What was the significance of a rectangular tank that would cause the squid to die? Is whatever caused these squid to randomly die the same thing that makes other species of squid impossible to keep in captivity?

    It's worth noting that I saw a documentary that referenced the Discovery channel show, not the show it's self.

    It was incredibly sad to see those creatures die. That would have been a dream come true to see one raised to maturity. I wish there was something I could do to help.
     
  2. Jean

    Jean Colossal Squid Supporter

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    The problem seems to be that the rectangular tank sets up some sort of harmonic vibration which disrupts the statolith/statocyst system (similar to our inner ear) this causes extreme disorientation and death. I think this is a best guess as to what is happening.......Steve, care to chime in?????

    As to raising one to maturity, the mind absolutely boggles about what size of tank you'd need and ow much food! :shock::shock:
     
  3. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    We did a number of things wrong:

    1) rectangular (or flat-sided) tanks for photographic purposes
    2) fed them an inappropriate-sized food (far too small for them); we gambled on flooding the tanks with copepods and the likes, but the prey should have been 1 to 1.5 times the size of the paralarval squid
    3) we used polyethylene tanks aboard the ship (and acrylic, fibreglass and concrete in our intitial trials)
    4) we had red light only aboard the ship

    Re tank shape, I've played with rectangular tanks subsequent to the ill-fated expedition; I think the vibration of the motors through the hull of the ship created havoc in the rectangular tanks aboard it, as squid don't behave the same way when in a rectangular lank on a laboratory (non-vibrating) bench.

    Re tank material (polyethylene), our tanks were new (we had 8 of them installed in the hull of the ship); each was 3200 litres in volume. These were far too large, and the material far too toxic for squid, even if we had them on a recirculating system, drawing from and flushing back to the sea. I cannot remember the flow rate we had in there ... it was so long ago now.

    Red light is a complete red herring; these animals are visual predators and they don't really give 2 hoots; we were pulling them from the very surface layers at night, to ~ 20 metres; they were quite happy with fluorescent white light in the lab, but we denied them this in the hull of the ship (almost completely black it was).

    The prey we offered them was far too small. We would have been better off trying to keep the squid alive in cylindrical acrylic tanks ~ 100 litres, then placing into these tanks 5 or 6 small euphausids or mysids, replenishing these as and when they were devoured (too much prey in at once and prey becomes predator).

    I try and forget all of this, and it's been a while since someone has asked (heavens, it was nearly a decade ago when we did this); I'm sure that someone will be able to do it because it really would be sensational to see these animals alive, and it is entirely possible to do so.
     
  4. sorseress

    sorseress Colossal Squid Supporter

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    No funding available for another try?
     
  5. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    I'll not do this again in any great hurry! Not for anyone! (Most of all, not me, not even to prove a point)
     
  6. Damien

    Damien O. vulgaris Registered

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    polyethylene might be toxic for squid ? This is an interesting thing if we considere that there are more and more toxic components in water like that ( rivers and seas) .

    Was the polyethylene itself suspected or could have been additives like phthalate ?

    Are there studies on toxic component presence in "archi" tissues ? ( except this one existing http://www.cebc.cnrs.fr/publipdf/2009/CBL5_2009.pdf
    )
    This could be an interesting subject...

    There will be no surprise if we considere that cetaceans tissues containes more and more toxic molecules.

    All the trophic chain is concerned of course, but it could provides interesting datas concerning squid threatening ( not only Archi) and it could concern human diet subject also (squid fishing)
     

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