Macroscopic structure of the fin-rays and their annuli in pectoral and pelvic fins of Chinook Salmon, Oncorhynchus tshawytscha.

Light microscopy, enzyme clearing, and staining techniques were used to describe the structure of fin-rays in pectoral and dorsal fins of adult and juvenile chinook salmon,Oncorhynchus tshawytscha. In addition, several decalcification agents, fixatives, and staining methods were employed to demonstrate and determine the nature of the fin-ray annulus (yearly growth ring). Etched, transverse sections of fin-rays were examined by scanning electron microscopy (SEM).