The Age of Cephs

[Fujisawas Sake]

Hello Everyone!

I've been on a bit of a hiatus since school let out, so I've been a bit outta touch with TONMO and all. I'm back now, so its time to start asking the tough questions

So I went to the Monterey Bay Aquarium the other day and one of the resident scientists asked me about how squid are aged (besides in oak caskets in the Napa Valley). So what are the best methods to determine the age of the squid, and how has this worked for determining the ages of large deep water squid?

Sushi and Sake,

John

 

[WhiteKiboko]

doesnt it involve the statolith? or is my ignorance showing?

 

[um...]

This journal is full of articles on cephalopod growth. I haven't read more than one page of any of them (), but I'd expect there to be something useful in there somewhere.

 

[tonmo]

Welcome back John! Here's a sushi lunchbox for you:


and a large sake:

To your question, look no further than TONMO.com! Check out our Science page here:

Ceph Science on TONMO.com

The fifth article down is a .PDF file titled "Estimating age and growth rate in Architeuthis dux" by ...

 

[Jean]

Hi John,

And no WK you're spot on! The statoliths have rings in them kinda like a tree. After CAREFUL grinding with silicon carbide (carborundum) paper followed by polishing with Alumina on felt (yes I know they're very small ) the rings can be counted. In many cases each ring equals one day.

I'll try to remember to post a couple of pics (I don't have them on this computer)

BTW in some cases there are growth lines in the gladius too

Cheers

J

 

[Phil]

John,

Have a look at this video:

http://exn.ca/video/?video=exn20030529-squid.asx

You will see Steve and Kat locating the statolith in Mesonychoteuthis. These things are tiny!


Phil

 

[Fujisawas Sake]

Thankee, Philbo Baggins!

All the best and thanks to everyone! This is part of something else I am working on with someone.

Long days, and pleasant nights.

John

 

[BigSquid8Me]

statolith

Two years ago I did a job shadow on Delsa Anderl of NOAA. Delsa studies the equivalent of a squid's statolith in Alaskan pollock (called an autolith), and she told me a few things about them. It's all about autoliths, but the concept should be relatively the same in squid. The autoliths are tiny deposits of calcium I believe, and a new layer is added every year (happy birthday!). I hear actually counting the rings is tough to do and usually the numbers need to be checked by two or three people. It's all a lot of fine microscope and scalpel work. Way beyond me.
In pollock, autoliths are absolutely gorgeous, very colorful. I did get a chance to skim a paper on statoliths, and I don't recall much being too different. Isn't the statolith part of the statocyst system?

BigSquid

 

[Jean]

Hi BigSquid,

Yep the statolith is in the statocyst chamber and is somewhat analagous to the fish otolith system. Seems to be a balance and orientation system a bit similar to our inner ear (correct me if I'm wrong here Steve!!)

Anyhow here are the promised pics. This is not a particularly good preparation (there's a whopping big crack right through the centre) but they do illustrate the increments This statolith is from Nototodarus sloanii and measured 0.775mm from the top rounded bit (Dorsal dome) to the pointy bit (rostrum)!

J