Annulus Validation, Time of Formation, and Mean Length at Age of Three Sunfish Species in North Central Florida

The visible opaque bands in transverse sections of sagittal otoliths from bluegill (Lepomis macrochirus), redear sunfish (L. microlophus), and redbreast sunfish (L. auritus) were verified as annual rings. The verification was done using intraperitoneal injections of oxytetracycline followed by otolith examination after the fish were at liberty for 1 year in a north central Florida pond. Injections of 75 mg/kg wet body weight resulted in the best rate of fluorescent ring formation. Saggital otoliths from bluegill and redear sunfish populations in Newnans Lake Florida were sampled monthly to determine the time of annulus formation. Annulus formation occurred for bluegill between March and July and for redear sunfish between February and July. Baseline data for length at age I to IV are presented for bluegill, redear sunfish, and redbreast sunfish populations in 58 lakes, 46 lakes, and 13 streams, respectively.

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