Tentarcticles (Mesonychoteuthis / Colossal Squid)

[Tintenfisch]

The hooks can all move independently. Whether they actually do is another question... having no recorded observations of them swiveling on a live animal, we don't even know if the animal actively rotates them (whether individually or at once), or whether they just turn all the way around 'so as' (Steve's gonna kill me for suggesting directional evolution) simply not to be pulled out when the prey thrashes. If they were stationary, I think there'd be a greater chance of losing them once the squid had grabbed a presumably struggling Patagonian Toothfish.

 

[Bald Evil]

Were any of the toothfish it was preying on recovered as well? Maybe the damage on the fish could shed some light on exactly what happens to the CS's prey (although I think I have a pretty good idea already ), and how it uses its hooks.

 

[THSMRTLCL]

beak length

Curious what the LRL measurement is on the new Mesonychoteuthis, does anyone have that?
-Casey

 

[WhiteKiboko]

Whether they actually do is another question... having no recorded observations of them swiveling on a live animal, we don't even know if the animal actively rotates them (whether individually or at once)

thats more along the lines of my query.... if they are controlled independently, thats an impressive mental/nervous capacity to control all of those hooks.... i dont doubt that theres much to learn about ceph brains, but is there a bit of a hierarchy to the intelligence? (octos then cuttles then squid then nautili or something similar)

 

[Steve O'Shea]

Hi Casey, the lower rostral length (LRL) was 37 mm; the max recorded for the species being 48mm, hence our reference to it being submature (or at least nowhere approaching the 'full size' that this animal can attain.
Kindest
Steve

 

[bonerici]

Ok I have a question. It seems according to the tonmo document that this colossal squid is a major part of the diet of the sperm whale. Also, this type of squid is extremely rare. I don't get it. You can't have it both ways, being a major part of a diet of this whale and extremely rare.

Which is it? Thanks!

 

[WhiteKiboko]

I believe finding an intact Colossal Squid is whats rare.....the number of beaks in a whales stomach is how they would determine its role as a food source....anyone feel free to correct me if im wrong.....if i remember correctly, it was first identified using an arm and/or tentacle fragment....

 

[Tintenfisch]

I believe finding an intact Colossal Squid is whats rare.....the number of beaks in a whales stomach is how they would determine its role as a food source....anyone feel free to correct me if im wrong.....if i remember correctly, it was first identified using an arm and/or tentacle fragment....

Yep. It's extremely rare in collections (7 total reported specimens including ours) but has to be very common in Antarctic waters to make up 77% by mass of a bull sperm whale's diet (Clarke 1980). Due to the Antarctic being... well, the Antarctic (as in a formiddable set of conditions to brave for a little fishing), there just hasn't been much in the way of encountering or actively seeking this animal for research purposes.


REFERENCE
Clarke, M.R. 1980. Cephalopoda in the diet of sperm whales of the southern hemisphere and their bearing on sperm whale biology. Discovery Reports 37: 1–324.

 

[bonerici]

Yep. It's extremely rare in collections (7 total reported specimens including ours) but has to be very common in Antarctic waters to make up 77% by mass of a bull sperm whale's diet (Clarke 1980). Due to the Antarctic being... well, the Antarctic (as in a formiddable set of conditions to brave for a little fishing), there just hasn't been much in the way of encountering or actively seeking this animal for research purposes.


REFERENCE
Clarke, M.R. 1980. Cephalopoda in the diet of sperm whales of the southern hemisphere and their bearing on sperm whale biology. Discovery Reports 37: 1–324.

Where can I find a copy of this reference? I didn't see it anywhere online, and it seems like we don't carry it at my library (University of Michigan). Thanks!

 

[Tintenfisch]

Yes, you probably won't find them online. Unfortunately the Discovery Reports are rare and expensive - if UMich doesn't have them you may have to interloan from another university (try WI?). :?

 

[bonerici]

Yes, you probably won't find them online. Unfortunately the Discovery Reports are rare and expensive - if UMich doesn't have them you may have to interloan from another university (try WI?). :?

Nevermind I found it, it was in storage not on the shelves.

One question, while I know that sperm whale hunting was restricted in '71 and banned completely about ten years later, the Japanese still hunted those whales for "scientific reasons." So shouldn't there be some more recent publications about squid in the diet of sperm whales from the Japanese?

I'm wondering if anything might have changed since Clark's report, as all his data is from around '67.

 

[Fujisawas Sake]

Are the hooks keratin or some other type of proteinaceous (sp?) compund?

 

[Steve O'Shea]

Re the composition of those hooks, I wouldn't want to say anything without some form of analysis first, and we haven't got anything like this lined up. Sorry.

Re a change in the sperm whale diet since Clarke's earlier work, it is certainly possible. I am convinced that a number of the larger, slower-moving cephalopods that we encounter (or used to) around New Zealand have been or are in the process of being systematically wiped out by large, relatively fast-moving fishing nets. Protecting the whales is one thing, but unless we protect its prey the whole thing is farcical. Ooops, I'm not allowed to express opinions like this.

Admittedly data is poor - all I have to go on is the fact that several large-bodied squid species have all but vanished from our waters (in areas where they once proved common), but I think that temporal changes would be apparent in sperm whale diet composition in New Zealand waters ..... if only we had archival samples (and we don't, and there has been very little work done on sperm whale diet down this neck of the woods).

I don't know what recent information the Japanese have published on the whales diet, but (intuitively) I don't think it would have changed that much in Antarctic waters - there's simply been too little fishing activity down there to alter deep-sea squid population dynamics (unless some other factor is responsible for the observed local changes).

It certainly is worth exploring.
Cheers
O

 

[Fujisawas Sake]

Steve,

But what really bakes my noodle is that Messie and Archi are apparently top-level predators in their field. My wife made the observation that large hunters on land need to either A) Eat a lot of small prey or B) Eat massive prey. My question is, could there be any MORE giant species of squid out there, and how are such large preds supported in their ecosystem? What are they eating down there?

Also, you and Kat seemed to indicate that the Messie has less ammonia than Archi. Assuming that affects buoyancy, wouldn't that mean that Messie is not only a more mobile beastie, but a more active hunter than Archi? Some time ago, you told me that Archis hang in the water column, using their buoyancy to hang about and simply snatch passing fish... If Messie is a more active hunter, does it chase down its prey? And how much food does it take to fuel these creatures?

What if they're munching on something we don't even know about yet? Is that possible?

And one more question: How much of a role do you think cephs play in the oceanic ecosystems overall? I'm beginning to see an interesting pattern here...

Sushi and Sake,

John

 

[Steve O'Shea]

But what really bakes my noodle ......

I never touched your noodle