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Otoliths of Florida largemouth bass Micropterus salmoides floridanus were collected monthly from three Florida lakes to determine the time of annulus formation. Although some growth ring compaction was observed in March, annulus formation was not observed until April. Young fish (ages 2–3) and females tended to form annuli earliest. Annulus formation was complete in all populations by July. It is recommended that largemouth bass otoliths should be collected between July and March for aging purposes to eliminate confusion in interpretation of the last annulus.
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Crawford et al. (1989) studied this question.
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