Fish scales comparing ctenoid and cycloid

Fish scales are composed of connective tissue covered with calcium.  Typically, soft-rayed fish have smooth cycloid scales and spiny-rayed fish have ctenoid scales.

Scales can be used for aging fish.  The annulii, or growth rings like on trees, are counted from the focus (where growth starts) outward.  By measuring the distance between annulii, along a radius, the growth rate of the fish can even be estimated.



FWC Facts:
The life expectancy for Gulf sturgeon is 20-42 years. The oldest age documented for a tagged and recaptured Suwannee River Gulf sturgeon is about 27-28 years.

Learn More at AskFWC