[quote]For all specimens, a section of the vertebral column was removed and either frozen in a plastic bag, dried, or
fixed in formalin and preserved in isopropyl alcohol. Vertebrae anterior to or directly under the first dorsal fin
were taken. A piece of the vertebral column was cleaned using a combination of steps. First, the haemal arch,
lateral processes, and most of the connective tissue were removed to expose the surface of the centrum. Then,
several centra were soaked for approximately five minutes in distilled water, followed by soaking in bleach to
further facilitate removal of connective tissue from the centrum. For larger centra, a longer soaking time was
needed, and immersion intervals ranged from one-half hour to six hours. The vertebrae were then soaked in a
concentrated solution of formic acid for two to four minutes to remove any remaining traces of bleach and to
etch the centrum surface.
The primary technique used to estimate age from vertebral centra was x-radiography (Cailliet et al. 1981,
1983a). The cleaned centra were x-rayed whole using a Hewlett-Packard Faxitron Series x-ray system (Model
No. 43805N) with Kodak Industrex M film (Readypack M-2). In one case, the x-radiograph did not produce
clear bands, and the vertebral centra had to be cut in half transversely, extraneous tissue ground away with a
dremel tool, and then x-rayed. In all cases, discernible bands could be distinguished.
A second band enhancement technique was used to corroborate the band counts derived for larger sharks.
This second technique was a modified version (Cailliet et al. 1983a) of the one first described by Von Kossa and
adopted by Stevens (1975). It basically involves replacing calcium salts in the centrum with silver, providing
distinct silver-impregnated bands which become quite dark after illumination under ultraviolet light. These centra were rinsed in distilled water for approximately fifteen minutes, then
immersed in a 1% silver nitrate solution, and immediately placed in a chamber where they were illuminated
by an ultraviolet light source. The length of light exposure ranged from 3 to 15 minutes, depending upon
centrum size. The centrum was then rinsed again in distilled water to remove excess silver nitrate. Vertebrae
were soaked in a 5% sodium thiosulfate solution for two to three minutes, removing excess silver and fixing
the chemical substitution. The final step was storage in 70% isopropyl alcohol.
The x-radiographs were viewed through a dissecting microscope or, for the larger ones, directly over a
fluorescent viewing glass, both with transmitted light. The silver-nitrate-impregnated vertebrae were viewed
directly with illumination focused laterally on the centrum.[/quote]
...........
You know, I actually had to dig a little to find this...it's from a symposium on white sharks, and I kept finding parts that were too interesting...
Personally, I think he's just making us, er....stew....for a while. So we'll all go fucking bananas when he announces the Oysterhead reunion.
(No pressure, STEWART. Seriously. We'd be pretty thrilled with a new symphonic work or soundtrack, promise.)