ABSTRACT

Life history parameters such as age-and-growth estimates are necessary for stock assessments and management of commercially and recreationally important species such as Red Snapper, Lutjanus campechanus. Perhaps the most widely accepted method to establish age in Red Snapper is by counting the number of opaque bands on otoliths (one increment consists of a translucent and an opaque band). However, when counting opaque bands, it is critical that the increments are validated as annular. Here, conventional mark-recapture methods were used on Red Snapper that had 168been injected with oxytetracycline (OTC). Sagittal otoliths from recaptured fish (N = 65, at liberty for >0.8 years) were sectioned along the transverse plane, and the number of opaque bands formed after the time of OTC injection were counted. All otolith sections were examined under a fluorescent microscope (blue-violet and white light). The widths of otolith increments were measured from the OTC mark to the start and end of each increment. Annual otolith increments were observed for recaptured Red Snapper that were at liberty for 0.8 to 11 years. The time of opaque band formation varied among individuals, occurring during all months, but most opaque bands formed from June through November, with peak formation in September (dorsal axis = 68%, ventral axis = 76% frequency). This summer–fall formation of opaque bands may have important implications for studies that attempt to link environmental disturbances to year-class abundance.