Shell from Pacific - help

[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>