Life history and ecology of the smallscale fat snook, Centropomus parallelus (Centropomidae) in east central Florida, and methodology to identify the regional snook species

Snook (Centropomidae) are euryhaline top predator species and highly prized game fish throughout their range, including Florida. Misidentification of the Centropomus species is a common problem among researchers, especially when working with small juveniles, which look alike. This study documented occurrence of four Centropomus species previously known to exist in Florida, and the first known occurrence of C. mexicanus in east central Florida. The morphological identification of these five centropomids species is supported by molecular analysis. This study provided a revised taxonomic key for identification of the five Centropomus species occurring locally. However, such key should be used with caution when applied to the identification of the C. parallelus - mexicanus complex, because these cryptic species are similar in appearance and their meristic characters overlap making it difficult to morphologically or meristically distinguish them.The life histories and ecology of centropomids have received little comprehensive examination, and all previous studies on the genus Centropomus in Florida refer to C. undecimalis. Limited information is available on the life histories and ecology of C. parallelus, C. pectinatus, C. ensiferus, and C. mexicanus from Florida waters. These species depend on freshwater habitats and are currently threatened by anthropogenic impacts and loss of critical coastal habitat due to shoreline development, herbicide use, water quality impacts, pollution, and fishing pressure.This study provides life history parameters for C. parallelus in east central Florida. Maximum ages estimated from thin-sectioned otoliths were 10 years for males and 12 years for females, and males grew faster than females. This species is a primarily a protandric hermaphrodite, with all the smaller individuals (<200 mm SL) being males, although a few fish appear to remain males throughout their lives. Like other Centropomids, C. parallelus is a carnivorous species, juveniles feed mainly on penaeid shrimps, and larger fish feed on more varied prey, mainly portunid crabs and teleost species.A pilot telemetry study showed the feasibility of using acoustic techniques to monitor movements of C. parallelus. Tracking of C. parallelus in the St. Sebastian River has provided evidence of habitat utilization, supporting that riverine habitats are critical to the species.