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How Is The Age Of Fish Determined?

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enotes | Valedictorian

Posted October 9, 2011 at 4:00 PM via web

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How Is The Age Of Fish Determined?

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fact-finder | Valedictorian

Posted October 10, 2011 at 4:00 PM (Answer #1)

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One way to determine the age of a fish is by its scales, which have growth rings just as trees do. Scales have concentric (increasingly larger circles with a common center point) bony ridges, or "circuli," which reflect the growth patterns of the individual fish. The portion of the scale that is embedded in the skin contains clusters of these ridges, called "annuli." Each cluster marks one year's growth cycle.

Sources: Academic American Encyclopedia, vol. 8, p. 113; Grzimek's Animal Life Encyclopedia, vol. 4, p. 49.

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