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Colloque
The otoliths, after being cleaned in alcohol and xyoll, are stored dry. The following manipulations are most useful for distinguishing the growth zones: 1. the otolith is ground on its convex surface; 2. then it is broken into two halves through the nucleus and is soaked in concentrated glycerine for about 24 hours; and 3. both halves are heated in a bunsen flame for approximately two minutes until they are dark brown. Thus prepared otoliths are examined in reflected light under a stereoscopic microscope at 25-50X magnification. Alternating dark brown and yellow zones show the age.
Colloque
The otoliths, after being cleaned in alcohol and xyoll, are stored dry. The following manipulations are most useful for distinguishing the growth zones: 1. the otolith is ground on its convex surface; 2. then it is broken into two halves through the nucleus and is soaked in concentrated glycerine for about 24 hours; and 3. both halves are heated in a bunsen flame for approximately two minutes until they are dark brown. Thus prepared otoliths are examined in reflected light under a stereoscopic microscope at 25-50X magnification. Alternating dark brown and yellow zones show the age.
