Florida's commercial and recre-ational shark landings represent a significant portion of the total U.S. Atlantic shark landings (NMFS, 1993). Shark landings have in-creased significantly during the past decade because human con-sumption of shark meat has become increasingly acceptable and be-cause, in Asian markets, the de-mand for shark fins is very high— as are the prices paid for them (NMFS, 1993; Brown, in press). The east-central coast of Florida is an important area for commercial and recreational shark fishing, and a wide array of shark species, includ-ing those examined in this study, are landed in this region (Trent et al., 1997; FDEP 1). Mercury, a toxic metallic ele-ment, has been shown to bioac-cumulate in fish tissue, and there-fore, fish can represent a major di-etary source of mercury to humans (Phillips and Buhler, 1978; Turner et al., 1980; Lyle, 1986). Methyl-mercury is the most toxic form of mercury for humans to consume (Meaburn, 1978; NMFS, 1993) and essentially all mercury found in fish muscle tissue (>95%) is in the monomethyl form (CH 3 Hg)(Grieb et al., 1990; Bloom, 1992). There-fore, the measurement of total mer-cury provides an approximation of. methylmercury and has been rec-ommended as the standard for regulatory monitoring (Bloom, 1992). Elevated mercury concentra-tions in fish have been a growing concern among resource manage-ment agencies. Apex predators, par-ticularly long-lived species such as billfishes (Förstner and Wittman, Hueter et al., 1995, and oth-ers) have been reported to accumu-late relatively high levels of mercury. In May 1991, the Florida Depart-ment of Health and Rehabilitative Services (FHRS) released a health advisory urging limited consump-tion of all shark species from Florida waters. 2 Owing to mercury concentrations in excess of U.S. Food and Drug Administration and State of Florida standards, FHRS recommended "adults should eat shark no more than once a week; children and women of childbear-ing age should eat shark no more than once a month." State of Florida guidelines recommended that fish containing less than 0.5 ppm of to-tal mercury should represent no dietary risk, fish containing 0.5 to 1.5 ppm of total mercury should be consumed in limited amounts, and fish containing greater than 1.5 ppm of total mercury should not be consumed. The 1991 health advi-sory regarding sharks in Florida waters was derived from a limited number of samples taken from re-tail sources and from studies that lacked important information re-garding species, capture location, sex, and size of sharks examined. Increased landings of sharks in Florida for human consumption (Brown, in press; FDEP 1) has prompted the need for more de-tailed information regarding mer-cury levels in Florida shark species. Consequently, we report here analyses of total mercury levels in the muscle tissue of three carcha-rhinids (bull shark, Carcharhinus leucas; blacktip shark, C. limbatus; and Atlantic sharpnose shark, Rhizo-prionodon terraenovae) and one sphyrnid (bonnethead shark, Sphyr-na tiburo) from the east-central coast of Florida.