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Steve O'Shea

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Hi

Welcome to Physiology & Biology, where we will attempt to answer those technical questions you might have on aspects of cephalopod biology, systematics (as in: what species is this? How do I identify my species? What makes this different from that? Where might I go to find out this or that?), and physiology (none of us is a physiologist, so help will be needed here from the cephalopod community). It is a huge field, and sometimes some of the responses will be taken straight from text books, sometimes we'll make them up and then duck for cover, and sometimes we might have to leave them in the 'too hard' basket, but we'll do our best. Moreover, for some questions there may be no known answer, or we might not know it (highly likely), but as many experts check out www.TONMO.com, I'm sure an answer will be forthcoming.

There are a number of online articles:
Guide to frequently used characters, character states and measures in cephalopods,
Articles on Architeuthis (the giant squid) reproduction and buoyancy, and large-squid-fixing notes,
Fact sheets on Architeuthis, Mesonychoteuthis (the colossal squid) and a few other squids that attain 'giant size',
And cephalopod biology, to name a few.

We've also gone LIVE with SQUIDCAM; see the same-titled thread right here. Lighting will be a challenge (for non-southern hemisphere folk at night), but as we'll have to have 24-hr lighting on the tank (albeit reduced at night, necessary to keep these visual predators alive), you should be able to see something. We'll also establish regular feeding times, so you can tune in and watch them devour their prey, 1-1.5 times their own size.

If you are interested in researching cephalopod systematics, or aspects of their biology or ecology, a number of research possibilities are detailed as announcements in this forum. That's not to say that this is the only research being conducted down here (in wonderful New Zealand), and if you have something else you'd like to do then you are more than welcome to approach us with ideas.

This thread has recently been split into two: Physiology & Biology of Cephs, and Marine Conservation. We've done this so as to more easily track the two types of thread. There is a lot of overlap between the two, and a few parallel discussions, so don't forget to check out Marine Conservation also (where you can learn all about the importance of cephalopods in ecosystems, and in the diet of whales and fish).

A lot of information posted on these threads can only be found on TONMO. Sometimes we post information that has yet to be published; some of it might never be published; sometimes we are thinking out aloud (and we might change our mind after discussion); sometimes we simply have fun. Join in.

Tony has done a marvelous job setting this up, and we thank him here for all of his help.

Read on, enjoy, and thanks for tuning in.
The team

 

Steve O'Shea

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Over the coming weeks Tintenfisch and I will post some 'you read it here first' articles. Welcome to TONMO.com live!
 

myopsida

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…Meanwhile, on a bed of papyrus floating in the South Pacific, a most strange phenomenon was underway.
 

Steve O'Shea

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......oh dear. Are Queen Sheetal and the tutu-clad cane toads about to be resurrected? That brings back fond memories of early days :goofysca: :heee:
 

BigSquid8Me

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Oh where oh where has Architeuthis gone?

Hi everyone! I'm new to tonmo.com, and I'm so glad I found my way here. Now I can ask questions and get answers! HOORAY!!! :D

I've got a proposition for all the folks out looking for Architeuthis. What if it's at the poles? It makes sense, doesn't it? The places they wash up and/or are caught trawling most (South Africa, New Zealand, Newfoundland, etc.) are right at the end of currents that circulate down/up from the poles! The water there is certainly cold enough for the ammonia to have neutral buoyancy (except when it gets too cold and it becomes less dense). I agree with the idea that New Zealand is just a breeding ground, so they probably die from exhaustion and rise to the surface after breeding.

Is this plausible to anyone else or am I crazy :jester: ?

~BigSquid8Me
 

Steve O'Shea

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Re: Oh where oh where has Architeuthis gone?

BigSquid8Me said:
I've got a proposition for all the folks out looking for Architeuthis. What if it's at the poles? It makes sense, doesn't it? The places they wash up and/or are caught trawling most (South Africa, New Zealand, Newfoundland, etc.) are right at the end of currents that circulate down/up from the poles! The water there is certainly cold enough for the ammonia to have neutral buoyancy (except when it gets too cold and it becomes less dense). I agree with the idea that New Zealand is just a breeding ground, so they probably die from exhaustion and rise to the surface after breeding.
Not a crazy proposition at all, but I don't think (I must stress 'think') this is the case.

There are two 'populations' of Architeuthis found in New Zealand waters; a West Coast South Island winter-spawning 'population' and an East Coast South Island summer-spawning 'population'. There is no genetic evidence to suggest that these two 'populations' belong to different species, although they are of comparable age, sex-ratio and size-class structure. The summer-spawning East Coast specimens almost invariably are caught beneath surface waters (~ 500 m depth) with a subantarctic water temperature signature, and the West Coast specimens almost invariably are caught beneath waters with a subtropical surface temperature signature (satelite imagery) - quite bizarre really because you would expect it to be the other way around. However, what surface temperatures tell us about water temperatures at 500 m is unknown (it is all I have to go by, that's all). Usually Architeuthis are caught in waters at temperatures between 7 and 9 degrees Celcius.

The paralarvae (= larvae) of Architeuthis have been caught in waters of subtropical nature, or those where the two subtropical and subantarctic water masses converge, but not in Antarctic waters. Moreover, adult/subadult Architeuthis have not been taken/trawled in Antarctic waters.

It is likely that Architeuthis is an oceanic species, living at ~ 500 metres depth in the middle of nowhere, tropical to subantarctic, until it nears maturity and migrates in to coastal regions to breed. Because both adults and paralarvae are caught in subtropical/subantarctic waters it is likely that the entire life is spent within waters of this nature. The missing/intermediate-sized individuals will occur outside of New Zealand waters, where there's not a lot of open-ocean trawling going on (at 500 metres depth). I believe this explains why the subadults/juveniles are so rare in collections (three 'juveniles' known/reported).
Cheers
O
 

Phil

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Steve,

Thanks for the fascinating information.

I don't think that I have ever asked you this before, but have you ever had the opportunity to examine any specimens of Architeuthis from North Atlantic waters? I am under the impression that there is little, if any, genetic variation from the South Pacific/Sub Antarctic specimens.

If they are separate populations then why are they so similar? Surely they would demonstrate some degree of speciation if the populations do not mix. Or, on the other hand, do you think there is basically one population that does indeed cross the equator and is truly global?

Cheers,

Phil
 

Steve O'Shea

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Phil said:
Steve,

Thanks for the fascinating information.

I don't think that I have ever asked you this before, but have you ever had the opportunity to examine any specimens of Architeuthis from North Atlantic waters? I am under the impression that there is little, if any, genetic variation from the South Pacific/Sub Antarctic specimens.

If they are separate populations then why are they so similar? Surely they would demonstrate some degree of speciation if the populations do not mix. Or, on the other hand, do you think there is basically one population that does indeed cross the equator and is truly global?

Cheers,

Phil
Heavens, I don't know how this post escaped my attention Phil; sorry - it's been ~ a month to the day.

There is no apparent genetic difference between Nth Atlantic, Sth Atlantic and Sth Pacific 'populations' of Architeuthis; nor is there any apparent morphological difference that cannot be discounted as one of preservation artefact, or damage. The same conclusion has been drawn based upon comparative examination of Architeuthis beaks from all regions.

HOWEVER, I still maintain that we have spatially and temporally separate 'populations' of Architeuthis in New Zealand waters: summer East Coast South Island and winter West Coast South Island 'populations'. Whether these intermingle/cross the equator, move from NZ to South Africa, migrate North to South poles or South to North, I just don't know. So many questions that keep me awake at 10:30pm thinking .... and sometimes into the wee early am hours.

Even when we/someone gets the imagery of this animal alive there'll be so many unanswered questions - all we'll know with that elusive imagery is what the animal looks like, how it suspends itself in the water column, possibly how it feeds .... but these are all just snapshots of a beast in time and space; the bigger picture, understanding the animals life history, will take many more years and much detective work to resolve. So, if you're 12 years old and interested in Architeuthis, believe me when I say there'll be plenty of mysteries left for you to tackle, even when I'm dead and gone (which, hopefully, will not be in the immediate future).
Cheers
O
 

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