A Guide to Otoliths from Fish of the Gulf of Mexico

The otoliths of teleost fish have many practical applications in fisheries science, many of which are only beginning to be fully exploited. In addition to age information, otolith microchemistry can also aid in stock identification (Edmonds et al., 1989). Analysis of banding patterns can be crossdated with tree-ring records to validate ages of long-lived fishes (Black et al., 2005), just as bomb radiocarbon signatures in otoliths can be referenced to known dates of atomic bomb tests in the 1950–1970s (Campana, 1997). Otoliths can also be used for species identification, which has practical applications for diet studies, micropaleontology, and taxonomy. Species within a family will have similarly shaped otoliths. However, the exact shape of the otolith is unique to each species. Otoliths grow continuously throughout a fish's life and otolith weight is generally demonstrably related to fish age and influenced by growth rates (Pawson, 1990). The two and three-dimensional shape of the otolith may also change dramatically as the fish gets larger. The goal of this report is to provide digital images of sagittal otoliths from common fishes in the northern Gulf of Mexico.Two images of each otolith are presented: the proxal and distal surfaces. Distribution information, unless otherwise noted, is from the Peterson Field Guide to Atlantic Coast Fishes (Robins et al., 1986), and shape categories were derived in part from Smale, et al. (1995). Otoliths have been categorized by shape and family.