Shell from Pacific - help

[wruzgul]

Hello,
I just recieved a shell and I want to know more about it. Where does it come from? What specie is it? etc.

Here are some photos:

<a href="http://rapidshare.com/files/207657186/pacific_shell.rar.html" target="_blank"><!-- m --><a class="postlink" href="http://rapidshare.com/files/207657186/pacific_shell.rar.html">http://rapidshare.com/files/207657186/p ... l.rar.html</a><!-- m --></a>

Apriciate any help!

[paul monfils]

This is an abalone shell.  It appears to be the red abalone (scientific name Haliotis rufescens) from western North America, which is the largest abalone species.  An abalone is a kind of gastropod mollusk, which is to say a kind of "snail".  It lives attached to rock surfaces and can hold on so tight that a man cannot pull it loose without using some kind of metal tool.  Abalone are edible and are often harvested for that purpose.  Currently they are protected by law in many parts of their range.  The row of holes in the shell is natural, and serves as a means for the animal to bring in water to its gills for breathing, and pass out wastes.  <span class="petit">--Last edited by Paul Monfils on 2009-03-10 22:00:40 --</span>

[wruzgul]

Thank you a lot. I'm impressed by you knowledge ;]

Actually I'm a chemist and I recieved this as my project. I need characterize the shell and I started doing reading about it. It seems that the structure of the shell is preety interesting and can lead to developement of new life vest and in my opinion many more useful things.

Thanks again for fast reply.

[wruzgul]

I have another question.
Is it possible somehow to determine the age of the abalone when it died leaving the shell? Maybe from the outside shell surface covered by some outgrowth?

[paul monfils]

Not by looking at the shell per se.  There are growth ridges on the shell, parallel to the lip.  The ridges themselves indicate periods of little growth, and the spaces between them periods of accelerated growth.  In shallow water species from temperate climates there are often annual growth ridges because the growth rate decreases all winter, and increases all summer.  In species like that you can often determine age by counting the ridges, just like the rings in a cut tree.  However, warm water species don't usually show annual growth rings.  They may have several periods of growth per year, based on cyclic availability of food species, minor variations in temperature, or other factors.  However, because the Red Abalone is a commercially important species, a lot of research has been done on its rate of growth under various conditions.  I'm sure there are tables in print that provide age-size correlations for various populations.  On the other hand, if you don't know where your specimen came from, even such information would probably not be helpful.  I'm sure the species grows a lot faster in Mexico then it does in Oregon.  <span class="petit">--Last edited by Paul Monfils on 2009-04-18 06:38:24 --</span>